manual on marine meteorology 2011 -...

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Manual on Marine

Meteorology 2011 ISSUED BY

DEPUTY DIRECTOR GENERAL

OF METEOROLOGY (WEATHER FORECASTING)

INDIA METEOROLOGICAL DEPARTMENT

PUNE – 411005

Manual On Marine Meteorology-2011

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FOREWORD

Weather information is a very important requirement for the mariners during their

navigation. They also need the forecast of weather during their voyage which is vital for

decision making. The Weather bulletins issued by India Meteorological Department are of

immense help to naval as well as commercial ships.

The storm bulletins/ Sea bulletins are issued by IMD on real time basis. Global Maritime

Distress Safety System bulletins are issued for high seas on operational basis. Special bulletins

for adverse weather are also issued by the Department. The port warnings are also issued by

IMD. “Manual on Marine Meteorology 2011” has been brought out to facilitate the mariners,

which details various types of bulletins, demarcations of various regions of Indian marine

neighborhood, various sub-offices, nature and validity of different bulletins.

A separate chapter on measurement of meteorological parameters is included in this

manual. Information of TurboWeb, a java web-based version of TurboWin is also provided for

fast coding and transmitting, error free Weather observations from ships. Climatology for

Arabian Sea and Bay of Bengal for more than 100 years is also provided in this manual.

Dr. A.B.Mazumdar, Deputy Director General of Meteorology(WF), Shri S.B.Gaonkar,

Director, Dr. P.C.S.Rao, Director, Shri S.P. Joshi, Asst. Meteorologist have designed and brought

out this publication. The suggestions offered by the other officers of DDGM (Weather

Forecasting) are acknowledged.

Date AVM (Dr). Ajit Tyagi

Director General of Meteorology

India Meteorological Department

New Delhi


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CONTENTS

1. Introduction .............................................................................................................................................................. 7

1.1 History of marine meteorological services .............................................................................................. 7

1.2 Weather services for marine community: ............................................................................................... 8

1.2.1 Marine meteorological services of IMD ............................................................................................ 8

1.3 PORT METEOROLOGICAL Office (P M O) ...............................................................................................11

1.3.1 Cyclone Warning Reasearch Centre,RMC Chennai ....................................................................12

1.3.2 Oil and Natural Gas Commission (ONGC) Cell .............................................................................12

1.4. Marine Meteorological forecast activities in other agencies, and need for linkages: .........13

2. Marine meteorological observations ...............................................................................................................15

2.1 Classification of Voluntary Observing Ships .........................................................................................15

2.2 Selected ships ....................................................................................................................................................16

2.3 Supplementary ships ......................................................................................................................................16

2.4 Auxiliary ships ...................................................................................................................................................16

2.5 International list of Selected, Supplementary and Auxiliary ships (WMO Publication No 47) ....................................................................................................................................................................................16

2.6 Recruitment of Voluntary Observing Ships ...........................................................................................18

2.7 Criteria of recruitment ...................................................................................................................................18

2.8 Programme for surface observations on board ships .......................................................................20

2.9 Special observations .......................................................................................................................................21

2.9.1 Coding of observations ..........................................................................................................................22

2.9.2 Observational platform .........................................................................................................................22

2.9.3 Observation from ships. ........................................................................................................................23

2.9.4 Vessel Information ..................................................................................................................................25

2.9.5 Rider Rules .................................................................................................................................................32

2.9.6 Moored buoys ............................................................................................................................................32


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2.9.7 Towers and Platforms............................................................................................................................32

2.9.8 Drifting buoys ...........................................................................................................................................33

2.9.9 Reception of data and their archival ................................................................................................33

2.9.9.1 Application of Marine Observations : ................................................................................34

2.10 IMD’s exclusive website on “Marine Meteorology” .......................................................................35

2.10.1 Automation of observations on board ship ................................................................................35

2.10.2 System Requirements .........................................................................................................................37

2.10.3 TurboWeb ................................................................................................................................................37

2.10.4 Why download Java?............................................................................................................................37

3. BULLETINS AND WARNINGS ................................................................................................................................40

3.1 Categories of bulletins and warnings ...................................................................................................40

3.2 Weather and sea bulletins .........................................................................................................................40

3.2.1 Types of bulletin ...............................................................................................................................40

Types of bulletins and warnings .........................................................................................................................41

3.2.2 Port Warnings ..........................................................................................................................................42

3.2.3 LIST OF STORM SIGNAL STATIONS .................................................................................................45

3.2.4 Bulletins for INDIAN NAVY ..................................................................................................................47

3.2.5 Coastal Bulletins .......................................................................................................................................50

4. The Global Maritime Distress and Safety System (GMDSS) ...............................................................52

4.1 Marine Pollution Emergency Response Support System for the high seas ..............................54

5. SHIP WEATHER CODE OBSERVATION CODE, FM 13-IX SHIP ...............................................................56

5.1 SHIP SURFACE OBSERVATION CODE FORMAT ...............................................................................56

5.2 DEFINITION OF GROUPS...............................................................................................................................57

6. Drifting Buoy Cooperation Panel (DBCP) ........................................................................................................73

6.1 National Data Buoy Program....................................................................................................................73

6.2 Format for Buoy Data Exchange .............................................................................................................74

6.3 FM 18-X BUOY – Report of a buoy observation ................................................................................75

6.4 Regulations for Buoy Observation Reporting ...................................................................................77


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6.4.1 General ......................................................................................................................................................77

6.4.2 Section 0 ......................................................................................................................................................77

6.4.3 Section 1 ...................................................................................................................................................78

6.4.4 Section 2 ...................................................................................................................................................79

6.4.5 Section 3 ......................................................................................................................................................80

6.4.6 Section 4 ...................................................................................................................................................80

6.4.6.1 .......................................................................................................................................................................81

7.Measurement of Meteorological Parameters ..................................................................................................83

7.1 General ..................................................................................................................................................................83

7.2 Wind Instruments ............................................................................................................................................83

7.2.1 Anemometer ..............................................................................................................................................83

7.2.2 Hand anemometer ...................................................................................................................................84

7.2.3 Digital hand anemometer .....................................................................................................................84

7.2.4 Wind vane ...................................................................................................................................................85

7.3 Aneroid barometer ..........................................................................................................................................86

7.3.1 Marine barograph ....................................................................................................................................87

7.4 Whirling psychrometers or Sling psychrometers ............................................................................88

7.4.1 Louvered screen .......................................................................................................................................89

7.4.2 Sea-surface temperature ......................................................................................................................91

7.4.2.1 Methods of observation of Sea-Surface Temperature ............................................................91

7.4.2.2 Sea-Bucket...............................................................................................................................................92

7.4.2.3 Intake and tank thermometers .......................................................................................................95

7.4.2.4 Hull attached thermometers ...........................................................................................................95

7.5 Visibility ...............................................................................................................................................................96

7.5 Cloud cover (cloud amount) ........................................................................................................................96

7.5.1 Cloud height estimation (Nh) .............................................................................................................97

7.5.1.1 Low Clouds (Cl) .....................................................................................................................................97

7.5.1.2 Middle Clouds (Cm) .............................................................................................................................98


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7.5.1.3 High Clouds (Ch) ...................................................................................................................................98

7.6 Weather (ww and W1W2) ...........................................................................................................................98

7.7 Waves ....................................................................................................................................................................98

7.7.1 Definition of Wind Wave: .....................................................................................................................98

7.7.1.1 Definition of Swell Wave ...................................................................................................................99

7.7.1.2 Wave direction ......................................................................................................................................99

7.7.1.3 Wave period ...........................................................................................................................................99

7.7.1.4 Wave height ......................................................................................................................................... 100

7.7.1.5 Tsunami Waves .................................................................................................................................. 101

7.8.1 Description Altocumulus ................................................................................................................... 101

7.8.2 Description Altostratus ...................................................................................................................... 102

7.9 Icing .................................................................................................................................................................... 104

7.9.1 Meteorological factors related to icing ........................................................................................ 105

7.9.2 Types of icing at sea ............................................................................................................................. 105

8. Wave Forecasting ................................................................................................................................................... 106

8.1 Freshening of the wind at constant direction ................................................................................... 108

8.2 Changing Wind Direction: .......................................................................................................................... 108

8.3 Slackening of the wind: ............................................................................................................................... 109

9. Guidelines to Marine Forecasting and Verification .................................................................................. 113

9.1 Introduction ....................................................................................................................................................... 113

9.2. General Guidelines ....................................................................................................................................... 114

9.3 Update Guidelines ......................................................................................................................................... 115

9.3.1 Wind forecast needs amendment if: ............................................................................................. 115

9.3.2 Sea condition ........................................................................................................................................... 116

9.3.3 Visibility .................................................................................................................................................... 116

9.3.4 Weather. ................................................................................................................................................... 116

9.4 Guidelines for Warning/Advisory. ...................................................................................................... 116

9.5 Interdepartmental Coordination ............................................................................................................ 117


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9.6. Verification ..................................................................................................................................................... 117

9.7 A sample scheme of Verification of GMDSS forecast .................................................................... 119

9.7.1 Verification for speed : It is done as per the following formula ..................................... 119

10. Observational Programmes ........................................................................................................................... 122

10.1 Programs of WMO ...................................................................................................................................... 122

10.2 Regional Programs ..................................................................................................................................... 123

10.2.1 International Indian Ocean Expedition(IIOE) ........................................................................ 123

10.2.3 VOSCLIM PROJECT ............................................................................................................................ 125

10.2.4 The WMO Voluntary Observing Ships Scheme ...................................................................... 126

10.2.5 VOSClim Project .................................................................................................................................. 127

10.2.6 Objectives .............................................................................................................................................. 127

10.2.7 Climate Research and Climate Prediction ................................................................................ 128

11. Current methodology/Different web sites and other aids ............................................................... 129

12. 1 APPENDIX 1 Ship Weather Log ................................................................................................ 132

12.2 APPENDIX 2 Address of Port Met Offices in India ......................................................... 136

12.3 APPENDIX 3 DIPRESSIONS / cYCLONIC STORMS DURING LAST 110 YEARS in India ............................................................................................................................................................................. 138


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1. INTRODUCTION

India Meteorological Department (IMD) provides the National Meteorological Service in our

country and is the principal government agency for all matters relating to meteorology and allied

sciences. Routine weather forecasts for shipping, fishermen, off-shore oil exploration etc. and issue of

special weather warnings for severe weather phenomena like tropical cyclones over the Indian seas

form the prime mandate of the department.

Purpose

The purpose of marine meteorological manual is to make available the information

about marine meteorological and related geo physical information, to marine users at sea or on

coast

1.1 HISTORY OF MARINE METEOROLOGICAL SERVICES

Weather service to marine interests is one of the important responsibilities of the India

Meteorological Department; it is also one of its earliest commitments. Adverse impact of many

destructive cyclones in the past over Indian coasts emphasized the need for a storm warning

service in the country. Consequently, a provincial meteorological organization was set up in

Bengal in 1867 to provide warning to ships in the Bay of Bengal. In 1880, a storm-signal service

was introduced for the west coast of India. During 1914, the transmission of weather bulletins

by wireless to ships was started by the Department. This service, which initially took the form of

wireless transmission (on request) to individual ships, was soon enlarged into a regular twice-a

day broadcast service. These bulletins were broadcast from coastal radio stations to all ships.

This service, with many improvements from time to time has continued to be in operation to

this day. In the year 1914, an arrangement was made for receiving voluntary weather

observations by wireless directly from ships at sea. Thus, an exchange of information between

the Indian Meteorological Service and Ships at sea began, and it is continued even to this day.

Around 1924-1925, the India Meteorological Department introduced an arrangement of

issuing on loan, meteorological instruments to individual Masters of ship, so as to assist them in

taking meteorological observations. Later a system of recruitment of ships for voluntary


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meteorological work known as Voluntary Observing Fleet (VOF) was commenced in 1946 under

the auspices of International Meteorological Organization. The ‘Safety of life at sea convention’

has also encouraged this.

1.2 WEATHER SERVICES FOR MARINE COMMUNITY:

Types of bulletins and warnings issued in the interest of Mariners are Sea area bulletins

(for shipping on high seas and for ships plying in coastal waters (unto 75 Kms off the coast

line)), Bulletins for Indian Navy, Bulletins for departmental exchanges, Port warnings, Fisheries

warnings, Four stage warnings, Bulletins for departmental exchanges, Port warnings, Fisheries

warnings, Bulletin for AIR, Warnings for Designated/ Registered users, Bulletins for Press and

aviation warnings.

The sea bulletins are issued by the Area Cyclone Warning Centres (ACWC) at Mumbai

and Kolkata. The coastal bulletins are issued by ACWC, Kolkata for West Bengal coast and

Andaman and Nicobar islands; by ACWC, Chennai in respect of Tamil Nadu, Kerala and

Karnataka coasts; by Cyclone Warning Centre (CWC), Visakhapatnam for Andhra coast by CWC,

Bhubaneshwar in respect of Orissa Coast by ACWC, Mumbai in respect of Goa and Maharashtra

coasts and by CWC, Ahmadabad in respect of Gujarat coast.

In normal (undisturbed) weather, there are two bulletins a day at fixed hours, known as

Daily bulletins. In the event of disturbed weather, a third bulletin known as Extra bulletin is

broadcast, if considered necessary. When a depression has actually formed, the third or extra

bulletin is invariably broadcast. When a cyclonic storm has developed, every attempt is made

to broadcast three additional bulletins a day. The three additional bulletins are known as Storm

bulletins, which together with the three bulletins mentioned above, make up a total of six

bulletins a day. The above bulletins are broadcast according to a schedule at fixed hours. In

addition, if any unexpected development of weather warrants urgent communication to ships,

this broadcast is in the form of a special bulletin, which may be broadcast at any time.

1.2.1 MARINE METEOROLOGICAL SERVICES OF IMD

For more than a century, India Meteorological Department (IMD) is providing forecast,

warnings and advisories, especially, during adverse weather situations for the coastal regions

as well as for the neighboring sea areas. At present the following divisions of the India


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Meteorological Department mainly carry out the Marine related functions. The present

activities of these units are summarized below in brief.

Northern Hemisphere Analysis Centre (NHAC) is located New Delhi at IMD Head

Quarter. NHAC after its inception in 1962 evolved into Regional Meteorological Centre (RMC),

New Delhi in 1968 under the World Weather Watch (WWW) programme of World

Meteorological Organization (WMO). Round the clock weather surveillance over India and

neighborhood is the main responsibility of this centre. Under WMO/ESCAP Panel programme,

RMC New Delhi was re designated as Regional Specialized Meteorological Centre (RSMC)

Tropical Cyclones, New Delhi in 1988 with the additional responsibilities like

Monitoring Cyclonic Disturbances over North Indian Ocean (Bay of Bengal and the

Arabian Sea)

Issue of Tropical weather outlook and tropical cyclone advisories to panel members

Bangla Desh, Maldives, Myanmar, Oman, Pakistan, Sri Lanka and Thailand.

Collection and archival of data pertaining to Tropical Cyclones over NIO and their

exchange with the member countries of the panel.

Research on storm surge, track and intensity prediction etc.

As per the recommendation of the Cyclone Review Committee constituted by the

Government a Cyclone Warning Division co-located with RSMC New Delhi was established in 1990

to coordinate and supervise the cyclone warning work in the country.

In the event of major pollution incidence on high Seas, the necessary meteorological support

is provided for Met-area VIII (N) {i.e. Bay of Bengal, Arabian Sea and north of equator} by Northern

Hemisphere Analysis Centre (NHAC), New Delhi, which is designated to function as Area

Meteorological Coordinator (AMC) under Marine Pollution Emergency Response Support System

(MPERSS)

1.2.1.1 THE INDIAN OCEAN AND SOUTHERN HEMISPHERE ANALYSIS CENTRE (INOSHAC) PUNE

This section is carrying out Marine meteorological forecasting services since 1966 and

originates advisories and meteorological forecasts over the Indian Ocean north of 10°S as per WMO

requirement. This centre provides following meteorological forecasts:


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Provides fleet forecasts for Indian Navy twice a day over the Indian Ocean to the north of

10°S between Longitude 60°E to 100°E.

Under the Global Maritime and Distress Safety System (GMDSS). A weather forecast are

originated twice a day for Indian Ocean area to the north of equator and consolidates the

forecast for Met-area VIII (N) with similar inputs for the Arabian Sea and the Bay of

Bengal received from Area Cyclone Warning Centres (ACWCs) Mumbai and Kolkata. The

frequency increases to four during tropical cyclone period.

1.2.1.2 AREA CYCLONE WARNING CENTRES (ACWCS) / CYCLONE WARNING CENTRE (CWCS)

ACWCs are functioning at Kolkata, Chennai and Mumbai and CWCs at Visakhapatnam,

Bhubaneswar and Ahmedabad. The main function of these centers is to keep a watch over the

weather developments in the Indian Seas and advise ships, ports, fishing vessels, the government

agencies and other concerned officials, general public etc. in time, regarding adverse weather

associated with cyclonic storms and depressions. These centers issue warnings and bulletins to the

various interests in the maritime states of India, coastal shipping and ships in the high seas for their

specified areas of responsibility. These bulletins include:

The 4 stage warnings viz. pre-cyclone watch, cyclone alert, cyclone warning and post

land-fall out look during cyclone situations

Weather and sea bulletins both for shipping on the high seas and those plying in coastal

waters (twice daily in undisturbed weather and 6 bulletins per day during storm periods)

Bulletins for Indian Navy also called Fleet forecasts (twice daily)

Bulletins for GMDSS (ACWC Mumbai & ACWC Kolkata only)

Bulletins for NAVTEX broadcast (ACWC Mumbai & ACWC Chennai only)

Port Warnings (daily once and more often as and when necessary)

Fisheries warnings (4 times daily)

1.2.1.3 MARINE DIVISION OF O/O DDGM (WF) PUNE.

The main marine related activities of this division in IMD at present covers the following

major disciplines:


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Observational support through coastal observatories and Indian Voluntary Observing

Fleet (IVOF) on high seas.

Collection, quality control and archiving of Marine Meteorological data regularly

through Ships requirement by 6 Port Meteorological Offices.

Instrumentation support to IVOF including regular check/inspection after installation of

Meteorological and marine equipments.

Forecasting of Marine safety information – i.e. Meteorological components including Sea

wave height, period, wind, weather and visibility.

Evaluates performance of individual ships, which have transmitted and submitted their

ship log books in time and also transmitted real time data during depression/ cyclonic

storms.

Maintains a close liaison with WMO in implementing its various schemes within the

countries.

1.2.1.4 MARINE CLIMATOLOGY SECTION (MCS) OF O/O ADGM(R) PUNE.

Under the Marine Climatological Summary Schemes (MCSS) of WMO (1963), the MCS was

established in IMD in 1971. The main responsibilities of MCS are:

Archiving of surface marine data and preparation of Marine Climatological Summaries

on yearly/decadal/30 year basis in the Indian Ocean, north of latitude 150S and between

200E to 1000E, which are exchanged with international marine centres.

Disseminates marine data to Global Collecting Centers at U. K. And Germany and other

agencies on mutual exchange basis

1.3 PORT METEOROLOGICAL OFFICE (P M O)

The functions of the Port Meteorological Office are varied and global in nature, adhering to

universal standards and methods of observation, to ensure consistency between nations. The

functions provided by the P M O. largely depend on the area or port being served and the type and

nature of marine traffic. At present there are six P M O.s functioning at Kolkata, Vishakapatnam,

Chennai, Kochi, Goa and Mumbai.

The general range of functions includes the following:


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To recruit ships of any nationality and to maintain a national Voluntary Observing Ship

(VOS) fleet.

To regularly visit ships recruited into the national VOS fleet, to provide ongoing training

to marine observers, maintain and inspect the meteorological and selected

oceanographic instruments.

To maintain accurate records of ships recruited into the national VOS fleet for

publication by World Meteorological Organization (WMO), about supply and recovery of

all instrumentations, checks and calibrations of instruments including dates.

To provide services to ships regardless of nationality and country of recruitment like

checking of meteorological instruments for marine observations.

To promote and maintain liaison with National Meteorological Service; neighbouring P

M O.s; Harbour authorities and shipping companies

To enquire from ship’s officers of any problems experienced concerning transmission of

meteorological oceanographic observations to a Land Earth Station (LES – Arvi for

India) or other facilities, including reception and adequacy of forecasts, bulletins and

facsimile broadcasts etc.

To support related national, regional and international marine meteorological and

oceanographic programs, such as VOS, VOSClim, *SOOP, *ASAP, *DBCP, *SOLAS, *WRAP and

Argo programmes.

*{SOOP – Ship of Opportunity programme, ASAP – Automated Shipboard Aerological Programme,

SOLAS – Safety Of Life At Sea, DBCP – Data Buoy Co-operation Panel, WRAP – Worldwide

Recurring ASAP Programme}

1.3.1 CYCLONE WARNING REASEARCH CENTRE,RMC CHENNAI

This centre was established in Chennai in 1972 and is engaged in research work on tropical

cyclones over the Indian seas and for providing necessary guidelines for operational cyclone warning.

1.3.2 OIL AND NATURAL GAS COMMISSION (ONGC) CELL

The forecasts and warnings issued by IMD are very essential for Oil and Natural Gas

Commission (ONGC) operations. The following meteorological services are being provided by IMD

for ONGC operations:


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Weather forecast 3 times per day regularly for Mumbai High, Godavari/ Krishna/

Cauveri basins and other fields.

Special weather forecast at the time of formation of depression/cyclone in the sea round

the clock.

Special weather forecast during monsoon period to give safe passage to the ONGC

vessels/rigs in emergency.

Monthly consolidated report of weather forecast every month and statistical

information as required for planning ONGC operations.1.4. Marine Meteorological

forecast activities in other agencies, and need for linkages:

Though there are various National agencies and institutes involved in Marine/Oceanic

interrelated activities pertaining to observational, developmental, modeling and other R&D activities,

IMD is having the mandate to provide services associated with atmospheric condition and it is also

the nodal agency with the primary responsibility and accountability to provide marine meteorological

services to user community through its various units,

The other centers offer inputs in observational/research mode to IMD. To mention a few:

Survey of India (SOI); for installation of tide gauges and preparation of coastal

bathymetry charts using GIS

o Department of Ocean Development(DOD)

o National Centre for Ocean and Antarctic Research (NCOAR) : An autonomous

organization under DOD with major responsibility to co-ordinate and execute

National Antarctic Mission, both Winter & Summer Expeditions.

o Indian National Centre for Ocean Information Services (INCOIS): An autonomous

organization under the Department of Ocean Development (DOD) of

Government of India is involved in Marine data collection and Ocean

observations. It is also engaged in prediction of Sea state and tidal currents in

specified areas on experimental basis.

o National Institute of Ocean Technology (NIOT): Another autonomous

organization under DOD is engaged in Ocean data boys under National Data

Buoy Programme (NDBP) and has also developed a storm surge prediction

model for east coast of India.


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o Indian Ocean Dynamics and Modelling (INDOMOD) Project: Department of

Ocean Development (DOD) has launched the INDOMOD project with 14 sub-

projects addressing specific elements pertaining to development of a wide range

of ocean-atmospheric models by six institutions viz., Centre for Atmospheric and

Ocean Science (CAOS)( Indian Institute of Sciences, Bangalore), Centre for

Atmospheric Sciences (CAS-IIT-Delhi), Centre for Mathematical Modelling and

Computer Simulation (C-MACS) Bangalore, NIO Goa, Indian Institute of Tropical

Meteorology (IITM) Pune and Cochin University of Science and Technology

(CUSAT) Kochi. Under these projects the following items have been

contemplated.

Wave model (WAM) for experimental ocean state forecast of wave parameters to

selected users

Operationalisation of coastal circulation (tidal) model

Storm surge models

Models of coastal upwelling

Numerical models for variability of the large-scale circulation of the

Indian Ocean

o Indian Institute of Technology (IIT at New Delhi & Kharagpur ): Mainly engaged in

development of storm surge models, ocean circulation models and sea state forecasting.

Indian Space Research Organisation (ISRO): Space Application Centre (SAC)/NRSA: for

remote sensing over the oceanic region. Also for validation/modelling/initialisation

processes.

o National Centre for Medium Range Weather Forecasting (NCMRWF) (DST): provides

medium range weather forecast over Oceanic region using a global atmospheric general

circulation model. These products form the basis for the Ocean models.

o Indian Institute of Tropical Meteorology (IITM): Mainly engaged in development of Ocean

models and coupled ocean-atmospheric models.

There are several National institutes that are engaged in similar and related marine

observational and forecasting activities and hence it is very essential that there be a linkage


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amongst all these overlapping activities inside and outside IMD so as to effectively align these

activities with strategic objectives to serve the marine community with appropriate MOUs for

complementary and supplementary mutually beneficial activities. However, the mandate for

providing the operational services to public and user agencies will be vested with IMD. Thus the

required information to the public and user agencies can be disseminated through a single

window system.

Back To Contents

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2. MARINE METEOROLOGICAL OBSERVATIONS

2.1 CLASSIFICATION OF VOLUNTARY OBSERVING SHIPS

Types of surface synoptic sea stations

Meteorological observing stations include surface synoptic sea stations of different

types :

Sea stations

Fixed sea stations :

Ocean weather stations :

Lightship stations

Fixed platform stations

Anchored platform stations

Island and coastal stations

Mobile sea stations

Selected ship stations

Supplementary ship stations

Auxiliary ship stations

Ice-floe stations

Automatic sea stations

Fixed sea stations

Mobile sea stations

Drifting buoy stations

Meteorological observing stations include surface synoptic sea stations of different

types. There are three types of mobile ship stations engaged in the WMO Voluntary Observing

Ships’ Scheme, namely:

(a) Selected ship stations;

(b) Supplementary ship stations;

(c) Auxiliary ship stations.


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2.2 SELECTED SHIPS

A selected ship station is a mobile ship station which is equipped with sufficient certified

meteorological instruments for making observations and which transmits weather reports in

the full SHIP code form.

The observations are entered in meteorological logbooks. With respect to

instrumentation, a selected ship should have at least a barometer (mercury or aneroid), a

thermometer to measure sea-surface temperature (either by the bucket method or by other

means), a psychomotor (for air temperature and humidity) a barograph and possibly an

anemometer. Selected ships constitute the large majority of voluntary observing ships.

2.3 SUPPLEMENTARY SHIPS

A supplementary ship station is a mobile ship station equipped with a limited number of

certified meteorological instruments for making observations and which transmits the weather

reports in an abbreviated SHIP code form. The observations are also entered in meteorological

logbooks.

2.4 AUXILIARY SHIPS

An auxiliary ship station is a mobile ship station, normally without certified

meteorological instruments, which transmits reports in a reduced code form or in plain

language, either as a routine or on request, in certain areas or under certain conditions. Ships

operating in this capacity are not equipped with certified meteorological instruments and are

requested to make and transmit weather reports only in certain areas or under certain

conditions.

2.5 INTERNATIONAL LIST OF SELECTED, SUPPLEMENTARY AND AUXILIARY SHIPS (WMO PUBLICATION NO 47)


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Selected, supplementary and auxiliary ships constitute an important source of marine

data which are used for various purposes all over the world. In analyzing these data,

Meteorological Services should be aware of the type of instrumentation on board a given ship,

or the particular method of observation when several methods are generally in use. For this

purpose WMO has compiled an International List of Selected, Supplementary and Auxiliary

Ships which is kept up to date through information supplied by Members and, for each ship,

contains particulars such as :

Name of ship

Call sign

Area or routes over which the ship normally plies

Type of barometer

Type of thermometer

Exposure of thermometer

Type of hygrometer or psychrometers

Exposure of hygrometer or psychrometers

Method of obtaining sea-surface temperature

Type of barograph

Various other meteorological instruments used aboard the ship

Types of radio equipment

Number of radio operators

Height, in meters, of the observing platform, measured from the mean water-line

Height in meters, of the anemometer

Regular updating of the International List of Selected, Supplementary and Auxiliary

Ships is needed because of the frequent changes in the international merchant shipping fleet

and also the changes in the recruitment of auxiliary ships in particular. As a rule, Members are

required to provide to the WMO Secretariat before 1 March each year a complete list of their

Selected, Supplementary and Auxiliary ships which were in operation at the beginning of that

year. This information could also be given in the form of amendments to the list valid for the

preceding year.


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2.6 RECRUITMENT OF VOLUNTARY OBSERVING SHIPS

Requirement to recruit ships

According to the WMO Technical Regulations, each Member shall arrange for the

recruitment of ships which are on the national register of that Member for the establishment of

mobile ship stations on them. In fulfilling this obligation, each Member contributes to the

common objective of obtaining sufficient coverage of meteorological observations over the sea.

Consequently, greater attention should be given to the recruitment of voluntary

observing ships. To satisfy international meteorological requirements for data density from the

oceans, the successive plans under World Weather Watch have shown the need for a continued

increase in the number of voluntary observing ships.

Meteorological Services in many countries are nowadays required to provide more

detailed information of the weather and sea conditions in coastal areas. Some Services have

successfully recruited ships of local companies to make and transmit observations during their

voyage from harbour to harbor along the coast. Such ships may be recruited as supplementary

or as auxiliary ships. Their observations have everywhere been found of great value.

2.7 CRITERIA OF RECRUITMENT

Several criteria can be used in deciding

1. Whether a particular ship should be recruited as a selected, supplementary or auxiliary

ship, to satisfy both national and international needs.

2. Questions which should be examined are whether all the necessary instruments can be

installed, whether the ships officers will have the time available for recording and

transmitting the observations and whether the necessary regular contact can be

established for the receipt of meteorological logbooks.


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3. Account must be taken by meteorological authorities of the normal ship duties of

navigation and radio officers and whether they would have sufficient time left over to take

and transmit observations.

4. Under the common objective of arranging for a sufficient number of observations from the

oceans, countries may also recruit ships of foreign registry. This is sometimes done by

arrangement between the Meteorological Services of two countries in cases where the

home port of certain ships is situated in another country.

5. Selected or supplementary ships thus recruited should, however, visit the ports of the

recruiting country sufficiently often to permit regular contact.

6. In order to avoid the entry of duplicate data into the international archiving system,

meteorological logbooks from ships of foreign registry should be procured and stored

through appropriate arrangements with the Meteorological Service of the country of

registry.

7. When the ship of foreign registry is recruited, the Member in whose country the ship

registered should be notified, unless a port in the country of the Member which recruits

the ship is considered to be its home port.

8. For the recruitment of an auxiliary ship, no prior arrangements are required with the

Meteorological Service of the country of registry.

9. The recruitment of voluntary observing ships is the responsibility of each Member

participating in the scheme and, for this purpose, Members should establish a suitable

organizational unit.

10. Shipping agencies should be contacted for enlisting their co-operation.

11. Appropriate measures should also be taken for the provision of instruments, instructive

material and other necessary documents to ships, for the collection and examination of

ships' logbooks, for visits to ships and for the various financial questions involved.

12. In this national unit, a special officer should be made responsible for the recruitment of

ships. In addition it is desirable that, in large ports, a port meteorological officer is

established.

13. Complaints about meteorological observations from a particular observing ship should be

directed to the Member with which the ship is registered.

14. If the ship was recruited by another Member, the Member receiving the complaint should

forward it to the Member concerned.


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2.8 PROGRAMME FOR SURFACE OBSERVATIONS ON BOARD SHIPS

Synoptic observations should be made at the main standard times: 0000, 0600, 1200 and 1800

UTC. When additional observations are required, they should be made at one or more of the

intermediate standard times: 0300, 0900, 1500 and 2100 UTC.

a. While taking observations, atmospheric pressure should be read at the exact

standard time, the observation of other elements being made within the ten minutes

preceding the standard time.

b. When operational difficulties on board ship make it impracticable to make the

synoptic observation at a main standard time, the actual time of observation should

be as near as possible to the main standard times. In special cases, the observations

may even be taken one full hour earlier than the main standard time i.e. at 2300,

0500, 1100 and 1700 UTC. In these cases the actual time of observation should be

indicated; however, these departures should be regarded only as exceptions.

c. When sudden or dangerous weather developments are encountered, observations

should be made for immediate transmission without regard to the standard times of

observation.

d. Observations should be made more frequently than at the main standard times

whenever storm conditions threaten or prevail. Meteorological Services may request

more frequent observations for storm warnings, particularly for tropical cyclones.

Special observations may also be requested for search and rescue or other safety

reasons.

e. Supplementary observations when required for scientific studies should be made at

intermediate standard times, subject to non-interference with navigation duties.

f. When an observation is made at 0300, 0900, 1500 or 2100 UTC in order to ensure

its transmission to a coastal radio station, it is desirable that the observation at the

next main standard time should be made for climatological purposes, and if possible

transmitted in accordance with normal procedures.

g. Ships’ officers should be encouraged to continue taking and reporting observations

while the ships are in coastal waters, provided it does not interfere with their duties

for the safety of navigation.


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h. Transmission of ships’ observations by INMARSAT is not constrained by the watch

keeping hours of radio officers aboard ship; transmission can be made at any time.

The distinction between two separate wave trains, and, in particular, the distinction

between sea and swell, can be difficult for an inexperienced observer. Sea waves are systems of

waves observed at a point which lies within the wind field producing the waves. Swell waves are

systems of waves observed at a point remote from the wind field, which produced the waves, or

observed when the wind field, which generated the waves no longer, exists.

The distinction between sea and swell can be made from the following criteria.

Wave direction: If the mean direction of all waves of more or less similar characteristics differs

300 or more from the mean direction of waves of different appearance, then the two sets of

waves should be considered to belong to separate wave systems.

Appearance and period when typical swell waves, characterized by their regular

appearance and long- crestedness, arrive approximately, i.e. within 20°, from the direction of

the wind, they should be considered as a separate wave system if their period is at least four

seconds greater than the period of the larger waves of the existing sea.

2.9 SPECIAL OBSERVATIONS

In relation to international programs of scientific or economic significance, observations

of a special nature are needed from ships at sea and WMO is requested to assist through its

Voluntary Observing Ships’ Scheme. One such example is the request for observations on locust

swarms in the seas around Africa, Arabia, Pakistan and India. This program is of great

importance to the agricultural economy in these countries concerned.

Another example is the logbook report of freak waves. A freak wave is defined as a wave

of very considerable height ahead of which there is a deep trough. It is the unusual steepness of

the wave, which makes it dangerous to shipping. Favourable conditions for the development of

freak waves seem to be strong current flows in the opposite direction to a heavy sea and

especially when this occurs near the edge of the continental shelf. The reports may contribute to

a mapping of these particularly dangerous areas and to a better understanding of the

phenomenon.


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2.9.1 CODING OF OBSERVATIONS

Ships’ observations are coded in the international meteorological codes published in the

Manual on Codes, Volume I (WMO -No. 306). The various code forms are given code names

which are sometimes included in the heading of the ship's report. In all cases, however, a 4-

letter identification group is used.

Another form of automation is the Marine Data Collection Platform (MDCP), which

consists of a hand-held computer, air temperature and air pressure sensor, transmitter and

antenna. The coded SHIP observations are entered into the computer and collected by Service

Argos satellite. In this case the meteorological logbook still has to be entered manually and

returned to the Meteorological Office in the traditional way.

Completely automated shipboard weather stations present difficulties. Proper locations

for sensors are not easy to find, particularly for wind and dew point, while equipment for

automated measurement of visibility, weather, clouds and wave height cannot be

accommodated in the confined space of a ship.

2.9.2 OBSERVATIONAL PLATFORM

Marine Observations include all meteorological and relate environmental observations

at the air-sea-interface, below the sea surface, and in the atmosphere above the sea surface.

Observations can be made using fixed or moving platforms, in situ or remote, using surface or

space based techniques. In situ measurements are essentially single point observations

representative of the surrounding the sea area. Remote Sensing Techniques lead to a large area

or volume representation particularly appropriate for observations of sea-ice. The platforms for

observations include ships Ocean Weather Stations (OWS), Manned and Unmanned light

vessels, Moored buoys, Drifting buoys, Towers, Oil and Gas platforms and Island Automatic


23

Weather Stations. Marine Observations can be made remotely from surface and space based

systems. At present, surface based remote sensing systems are available to measure

precipitation (Weather Radar), near surface winds (Doppler Radar), Surface Ocean Currents,

Surface Wind and Sea State (Microwave Radars). Remote Sensing from space is used for the

measurement of many surface marine variables. It provides bulk of sea state, wind and sea

surface temperature date over the World’s Oceans.

2.9.3 OBSERVATION FROM SHIPS.

Ships, which undertake meteorological observations, should be equipped for

observing or measuring the following elements:

(a) Position of the ship;

(b) Wind speed and direction;

(c) Atmospheric pressure, tendency and its characteristics;

(d) Weather-present and past;

(e) Clouds(amount, type and height of base);

(f) Visibility;

(g) Air temperature;

(h) Humidity;

(i) Precipitation;

(j) Sea-surface temperature;

(k) Ocean sea-waves and swell-height, period and direction;

(l) Sea ice and/or ice accretion on board ship, when appropriate;

(m) Course and speed of ship.

Automated or Partially Automated Systems on board ships have been developed both

for observing and data transmission. Satellite Communication System is now in wide use for

dissemination of Ships’ observations. It employs the use of meteorological geo-synchronous

satellites (GOES, METEOSAT, GMS), commercial satellite systems (INMARSAT), System

Argos(This system is primarily designed for location as well as data transmission and is limited


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by the number and the orbital characteristics of the National Oceanic Atmospheric

Administration polar orbiting satellites. Argos can be used for the communication and

processing of ARGO Floats.)

There are three categories of observing vessels in the Voluntary Observing Fleet.(1)

Selected, (2) Supplementary and (3) Auxiliary. Ships of both Selected and Supplementary

categories take and transmit observations all over the world in home as well as in foreign

waters. Ships of the auxiliary category normally report observations only when plying in areas

where shipping and meteorological observations are sparse. Services rendered by these ships

are purely voluntary and the India Meteorological Department gives Excellent Awards to the

Ships’ officers in the form of books of scientific and general interest as a token of appreciation of

their meteorological work. In addition, certificates of merit are also issued to ships and ships’

officers whose work is considered commendable.

The fixed sea stations and Voluntary Observing Ships (VOS) are key components of the

Global Observing System (GOS) and climate research. At the same time, however, it has been

recognized that these observations are subject to keying errors, coding errors, calculating errors, etc.

To achieve an optimal control of the quality of the observations, before they are used in real time, the

quality control has to be carried out at the root, by the observers themselves.

In order to improve the accuracy of, and confidence in, meteorological data collected by

Voluntary Observing Ships (VOS), a subset of the voluntary observing fleet has been nominated

and is referred to as the VOSClim. Observations from vessels belonging to the VOSClim are

regarded to be of the highest quality and will be used in a similar way to those collected by land

based Climate Reference Stations.

In order for the data to be of the required quality, additional metadata (Vessel

Information) needs to be collected and stored by the recruiting country. The metadata required

by WMO is detailed in WMO publication No. 47, Annex V, and collected on the VOSClim

recruitment / update / de recruitment advice (Form 001).The numbered fields are for

information required by WMO for every VOSClim vessel and must be completed according to

the instructions contained in WMO publication No. 47, Annex V.

The fields that are not numbered are for national use and may optionally be used to record

information about a country’s Voluntary Observing Ship. The information in these fields is not

required by WMO for the VOSClim vessels and it is therefore up to each country to decide if and how


25

these fields are populated. This form is intended to be used as a record of the recruitment of a vessel

into the VOSClim program, a reference to its systems while active in VOSClim and to record and

advise its de recruitment from VOSClim (by filling in the appropriate de recruitment details at the top

of the form).

The Port Meteorological Officer for her/his own records need only collect installation

dates and serial numbers. If there are changes to any details of the vessel, such as to the name,

call sign or flag, an update copy of the form should be completed and attached to the original

(master) form containing the correct details, with a plain language explanation included in the

‘comments’ field.

If the vessel is decommissioned by one country and recruited by another, the original

country’s F 001 should be marked to show the de recruitment, and a new recruitment form be

filled in by the new country. This should include a comment explaining the vessel’s previous

VOSClim service for the initial country.

2.9.4 VESSEL INFORMATION

This information is required to uniquely identify the vessel in the WMO database, and

supply some general guidance as to the kind of observations that can be expected from her.

Vessel Name (1) The registered name of the vessel (e.g. Reflection).

Call sign (2) The Ship’s call sign (e.g. VNSB).

IMO Number (3)

The numbers issued by the International Maritime Organization (e.g. 8717283) to uniquely

identify the vessel. This number stays with the vessel even if the name and call sign are changed

(Like R T O registration No to a motor vehicle).

Recruiting Country (4)

The International Organization for Standardization (ISO) code for the country whose

Meteorological Service recruited the vessel (This will be a 2-character code, e.g. IN for India). As


26

stated above, if the vessel is desecrated by one country and recruited (commissioned) by

another, a de recruitment F 001 should be appended to the original country’s F 001 containing

appropriate annotations in the ‘Comments’ field, and a new recruitment form be filled in by the

new country. This should include a comment explaining the vessel’s previous VOSClim service

for the initial country.

VOS Type (9)

The 2-digit WMO code (as detailed in WMO publication number 47, Annex V) for the

type of reporting ship in question (e.g. selected, supplementary, auxiliary).

Automation (10)

The level of automation of the observations. This is a 1-digit code as defined in WMO

publication number 47, Annex V, and indicates if the observation is fully automated, or if there

is some manual input, and the degree of the manual input.

Baseline check (11)

A 1-digit code (e.g. 1 for fully automated) as defined in WMO publication number 47, Annex V, to

indicate if the automatic observing equipment can produce a periodic baseline check to ensure

satisfactory operation.

Flag

The country of registration of the vessel (e.g. India). This information is not required by

WMO, but is included as it may be of interest to the recruiting country

Home Port

The home port of the vessel (e.g. Port Chennai). Again, this information is not required by

WMO. However it may be of interest to the recruiting country and may also be used to reflect a

commonly visited port if no home port exists.

Year of Construct. The year of construction of the vessel (e.g. 1998).

Date of Recruitment/De recruitment


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The date the vessel was commissioned / decommissioned into VOSClim (e.g. 26 January

1999). If the vessel was previously, or will subsequently, be operating as a VOS, or as another

country’s VOSClim, this should be mentioned in the ‘Comments’ field at the end of the form.

Routes (12)

Code number (e.g. enter 9 for the Australia-Pacific Islands route) for the areas or routes

on which the ship usually operates. Each recruiting country has defined its own set of routes,

which can be found in WMO publication number 47, Annex V. These routes differ from country

to country and reflect the routes used by the country defined in (4).

3hr/6hr/irreg

The frequency with which observations are normally performed, either every 3 hours, every 6

hours or at irregular intervals. Depending on operational requirements, observations may

occasionally be performed more or less frequently (e.g. enter ‘3' for three hourly observations).

Details of Ship’s Manager

The contact details of the vessel’s manager. This may sometimes be the ship’s owner.

This information is intended for local use only, and is not required by WMO. Therefore these

fields can be filled in to suit local needs.

Details of Ship’s Agent

The contact details of the vessel’s agent, or representative, at the port of recruitment.

This information is only intended for the PMO to keep a record of how to contact the local agent,

should the need arise, and is not required by WMO.

Vessel Layout

This information is required as metadata to attempt to model airflow and temperature

fields around the vessel to correct or explain anomalies in the recorded data set.

Vessel Type (5)

A 2-letter code as defined in WMO publication number 47, Annex V, defining the type of

the vessel (e.g. GC = General Cargo, BC = Bulk Carrier, RV = Research Vessel).


28

Gross Tonnage The gross displacement of the vessel, expressed in metric tonnes (e.g. 4157 t).

This is for local use only.

Dist of Bridge from Bow (8)

The distance from the bridge front extremity to the bow of the vessel in meters,

expressed to the nearest 1/10 m (e.g. 36.6 m) as recorded in the ship’s survey documentation.

Dimensions (7)

The dimensions of the vessel expressed in meters to the nearest 1/10 m. These

parameters are defined in WMO publication number 47, Annex V:

a. Length The length over all (LOA) of the vessel (e.g. 94.9 m),

b. Breadth The moulded breadth (beam) of the vessel (e.g. 20.3 m),

c. Freeboard The average freeboard of the vessel as measured from the maximum summer

loadline (e.g. 2.6 m),

d. Draught The average vertical distance between the vessel’s keel and the maximum summer

loadline (e.g. 7.9 m)

e. Cargo ht.

The average height of the cargo above the maximum summer load line on the particular

route where observations are made (e.g. 6.5 m). If the cargo is below the main deck (e.g. the

vessel is traveling in ballast or is a bulk tanker), report the height of the main deck itself.

Vessel Digital Image (6)

A two-letter code as defined in WMO publication number 47, Annex V, advising the

availability of a digital image. The naming convention for the image file(s) is in the following

format:

xxxxxxxxxyyyymmddaaa...aaa.jpg where

xxxxxxxxx IMO number (a nine digit number, include leading zeros if applicable)

yyyymmdd year, month, day

aaa...aaa short description of the photo


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Example: 00085124520020214balloon_launcher_port_side.jpg

Submit the image(s) on a floppy disk together with Form 001.

Location of Observation Points

The distances of observation points to fixed points on the vessel expressed in meters (to

the nearest 1/10 m):

a. Height of barometer (15)

The height of the barometer above the maximum summer load line (e.g. 14.2 m),

b. Height of thermometers (23)

The height of the thermometers above the maximum summer load line (e.g. 16.2 m),

c. Height of anemometer* (30)

The height of the anemometer above the maximum summer load line (e.g. 27.2 m),

d. Height of anemometer** (31)

The height of the anemometer above the deck on which it is installed (e.g. 21.8 m),

e. Height of visual wind/wave observation point (38)

The height above the maximum summer load line of the visual wind / wave observation

point (usually at bridge level, e.g. 14.2 m) ,

f. Dist of anemometer (from bow) (33)

The distance of the anemometer from the bow of the vessel (e.g. 36.6 m),

g. Dist of anemometer (from centre line) (34)

The horizontal distance of the anemometer from the longitudinal center line of the

vessel. Indicate if the anemometer is located to the port or starboard of the center line (e.g. 2.2

m to port),

h. Depth of sea surface temperature (28) The depth of the sea surface temperature sensor

below the maximum summer loadline (e.g. 4.5 m).


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Communications

These details are not required by WMO and are intended for local use only and should

include the vessel’s contact numbers for voice/data communications (e.g. Inmarsat, Radphone,

Email address, Facsimile number). For Inmarsat, indicate the type, e.g. A, B, C, M

Equipment

This page is intended to keep track of the equipment installed on the vessel. For each

instance of removal/replacement of a piece of equipment (and calibration of the barometer/

anemometer) it is intended that a new copy of the form is completed with only the relevant

details. It should be attached to the original form.

Be sure to include the name of the vessel in question on the top of page two, in case the

form cannot be printed back to back. The only information required by WMO is where the fields

contain WMO reference numbers as defined in WMO publication number 47, Annex V. The fields

without numbers are designed to keep track of information for local use only.

Instrument The instrument that the related columns refer to (e.g. Barometer).

Make The make/model/series number of the instrument (e.g. N&Z DA MkII).

Owner The owner of the instrument (e.g. India Meteorological Department IMD). This

column is intended for use by the PMO to keep track of her/his equipment.

Type

A code indicating the type of instrument in question (e.g. ALC = alcohol thermometer)

These codes are defined in WMO publication number 47, Annex V. Make every attempt to insert

a meaningful type, i.e. include a make where the instrument type consists of only letters and

numbers.

Serial no. The serial number of the instrument (e.g. CBM 153). This column is intended to be

used by the PMO to keep track of her/his equipment.

Exposure


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A code, or plain text indicating the conditions of exposure of the instrument (e.g. A =

aspirated, SL = sling, US = unscreened).

Location

The location of the instrument (e.g. chart room, monkey deck, etc.). For some

parameters different units can be used and these should be specified here. Also the usage of the

anemometer should be specified (see column 36 of WMO publication number 47, Annex V)

Date in / last calibrated

The date when the instrument was installed on the vessel using the following format:

dd/mm/yyyy (e.g. 30/05/2001). To be filled in at recruitment of the vessel, when a new

instrument is added, or on a new form when an instrument is replaced. Also to be used to record

the last date of calibration by attaching a separate form F 001 with the calibration date each

time a calibration is performed.

Date Removed

The date when the instrument was removed from the vessel in the above format

(dd/mm/yyyy e.g. 30/05/2003). To be filled in when an instrument is removed, or when the

vessel is decommissioned.

Publications Supplied to Ship

Each publication supplied to the vessel should be recorded here by placing a check in

the appropriate box or writing its title in the blank space if it is not listed.

Footnotes

Any points of importance that have not been included on this form and should be

submitted to WMO should be recorded here, (e.g. ‘Barometer located in pressurized

wheelhouse, readings taken only when the external door is open'). This includes information for

which there was insufficient room provided on the form.

Comments/Remedial Action

Any points of importance that have not been included on this form and need not be

submitted to WMO should be recorded here.

Recruiter Identification and Date (42)


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Before submitting the form, print your name (e.g. S P Joshi), date (e.g.12/05/2004) and

the port you are in (e.g. Port Mumbai), and sign. Keep a copy of the completed form for your

records, and submit the original to your national VOSClim focal point.

PMOs are expected to follow the guidelines given by WMO as Rider Rules while visiting

the ships.

2.9.5 RIDER RULES

1. Always make your presence known to the Captain and Chief Officer when visiting the

ship.

2 .Be cognizant of ship customs and protocol.

3. Carry your own tools and do not borrow ship’s tools.

4. Wear appropriate clothing and shoes.

5. When there is a lot of activity on the bridge, limit your questions and conversation

2.9.6 MOORED BUOYS

A typical moored buoy designed for deep ocean operation is equipped with sensors to

measure the elements, like Wind speed, Wind direction, Atmospheric Pressure, Sea-surface

temperature, Wave height and period, Air temperature and Relative humidity. Additional

elements measured by some data buoys are, Wave spectra (directional or non directional), Solar

radiation, Surface current, salinity, Sub surface temperature.

In addition to the meteorological and oceanographic measurements it is usual to

monitor buoy location and various housekeeping parameters to aid in data quality control and

maintenance.

2.9.7 TOWERS AND PLATFORMS:


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On towers (usually in relatively shallow waters close to shore) it is possible to

operate standard automatic weather stations, similar in design to land automatic weather

stations.

2.9.8 DRIFTING BUOYS:

Drifting buoys have been used for many years in oceanography, principally for the

measurement of currents; however the development of reliable satellite tracking and data relay

systems has led to a dramatic increase in the numbers of ocean drifting buoys deployed and

significant development has taken place in the sensor capabilities of drifters for meteorological

and oceanographic purposes.

2.9.9 RECEPTION OF DATA AND THEIR ARCHIVAL

Transmission of ship’s observations to the shore

2.9.9.1 INMARSAT

Ship reports can be transmitted readily to a Coast Earth Station (CES) which has been

authorised to accept these reports at no cost to the ship. The national Meteorological Service of

the country operating the CES pays the cost, which is usually less than the cost of a report

received via coastal radio. There are a number of such CESs in each satellite footprint and they

are listed, together with the area from which they will accept reports, in WMO-No. 9, volume D,

Part B. Code 41 is the INMARSAT address which automatically routes the report to the

Meteorological Service concerned. To place a limit on the costs incurred by a national

Meteorological Service, a CES may be authorised to accept reports only from ships within a

designated area of ocean. These limits should be drawn to the attention of the relevant ship’s

officers when recruiting a ship under the Voluntary Observing Ships Scheme. A radio operator is

not needed to transmit the report, and hence transmission is not restricted to the operator’s

hours of duty.

2.9.9.2 COAST RADIO STATIONS

Ship reports can be transmitted by radio telegraphy to a coastal radio station which has

been authorised to accept these reports at no cost to the ship. (The costs are met by the country

operating the coastal radio station, in many cases by the national Meteorological

Service).Weather reports from mobile ship stations should (without special request) be


34

transmitted from the ship to the nearest coastal radio station situated in the zone in which the

ship is navigating. If it is difficult, due to radio propagation conditions or other circumstances, to

contact promptly the nearest radio station in the zone in which the ship is navigating.

Members may issue instructions to their mobile ship stations to the effect that their

weather reports may be transmitted via one of their home coastal radio stations designated for

the collection of reports.

The ship weather report must be addressed to the telegraphic address of the relevant

National Meteorological Centre. The address should be preceded by the abbreviation "OBS" to

ensure appropriate handling of the message at the coastal radio station. The coastal radio

station must forward the report to the National Meteorological Centre with minimum.

2.9.9.1 Application of Marine Observations:

Meteorology: The real-time marine data are vital to alert the coastal population about

impinging natural disasters such as depressions and cyclones and to develop reliable

operational weather forecasting model.

Oceanography: The long term oceanographic data collected will enhance our understanding of

ocean circulation.

Validation of Satellite data: The in-situ data collected by data buoys are being used to validate

satellite data like wind speed, waves, sea surface temperature etc. and assimilation of this data

into operational sea state models.

Offshore Installations, Ports and Coastal Structures: The availability of reliable data on waves,

winds and currents will be highly useful in the design of various coastal and offshore structures

Fisheries: The sea surface temperature and water quality parameters obtained by would be

useful in identifying the potential fishing zones.

Environmental Impact assessment: The data will be useful for continuously monitoring coastal

and marine environment


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Shipping Industry: The data on sea state particularly wind, wave and currents could be used in

the navigation.

2.10 IMD’S EXCLUSIVE WEBSITE ON “MARINE METEOROLOGY”

IMD has developed an exclusive website on “Marine Meteorology”, and it is available on

internet at following address:

http://www.imdpune.gov.in/weather_forecasting/Marine/index.htm

This website is prepared keeping in view the fundamental aspects of Marine

Meteorology, considering the increased concern among the maritime community about a

variety of environmental issues. The Website meets the critical needs of Port Meteorological

Offices as well as the observers on board the ships and meets the basic needs of Port

Meteorological Offices . The Website is useful to Intermediate, Advance (revised) and met

II trainees of IMD Meteorological Training Centers.

There are various Forms, Lecture Notes, Codebook, Presentations, softwares etc

available in this website. It will be useful for Port Meteorological Offices while recruiting the

ships and also for the observers on board the ships. Port Meteorological Offices can print these

forms. It will provide training to the marine observers and Port Met Officers in handling and

maintenance of meteorological instruments. ‘Hindi’ version of homepage is also available.

The website contains video tutorials. There are 13 no of “Video Tutorials” available for

viewing. It is hoped that mariners will get more information on “Marine Meteorology “after

viewing the tutorials. Various users from maritime community like Indian Navy, shipping

companies etc have given a very good response to the website.

Technical guidance to mariners is also provided through internet.

2.10.1 AUTOMATION OF OBSERVATIONS ON BOARD SHIP

Automation of shipboard observations has been advanced by the advent of personal

computers and satellite communications. In one form the observations are taken manually in

http://www.imdpune.gov.in/weather_forecasting/Marine/index.htm


36

the traditional way and then entered into a personal computer, which may be in the form of a

laptop or notebook. The computer programme recommended by WMO and developed by

KNMI, Netherlands, namely “TURBOWIN 4.5” is available on internet at following website

http://www.knmi.nl/onderzk/applied/Turbowin/Turbowin.html

The coding of ship data can also be done online through KNMI‘s website. Turbowin

contains observation-checking routines, which are applied on the observations before they are

transmitted. Turbowin is a user-friendly system with over 200 built-in quality checks. It allows

the automated compilation of observations on board ships and fixed sea stations, their

downloading to disk and their subsequent transmission ashore and thence to a Meteorological

Centre, by using Inmarsat, ftp, E-mail or other specific communication facilities and the Global

Telecommunications Network. The program assists the observer with many menus, pictures,

photos, forms, helps pages, output possibilities, automated calculations etc.

The TURBOWIN 4.5 can:

(a) Provides screen prompts to assist with data entry;

(b) Calculates the true wind, MSL pressure and dew point;

(c) Checks validity of some data, e.g. month in range 1–12

(d) Stores the observation in SHIP code on disc and prints it out for transmission;

http://www.knmi.nl/onderzk/applied/turbowin/turbowin.html


37

(e) Formats the observation in IMMT format and stores it on disc or transmits the data to

a shore station via a satellite system.

2.10.2 SYSTEM REQUIREMENTS

The computer or INMARSAT-C terminal on which the program is to be installed should

have

MS Windows 95/98/Me/NT/2000/XP onwards

Extra requirement only for Windows 95 and NT users: Internet Explorer 4.0 or higher

High Colour (16-bits) or better screen setting

Screen resolution 600 * 800 (minimum)

If the ship is equipped with INMARSAT-C, TURBOWIN 4.5 can be installed on the

INMARSAT terminal and transmitted without re-keying. In addition to filling in a meteorological

logbook the compact diskette of observations in IMMT format is sent periodically to the

Meteorological Office.

2.10.3 TURBOWEB

What is TurboWeb?

TurboWeb is a web-based version of TurboWin4.5. For running TurboWeb on your

computer you need to install Java Runtime Environment (JRE). The set up file is freely available

on internet, on JAWA website. Once (JRE) is installed there is no need of installing Turbowin

software on your computer. When you download and install Java software, you are free of spy

wares, and viruses

2.10.4 WHY DOWNLOAD JAVA?

There are lots of applications and websites that won't work unless you have Java

installed, and more are created every day. Java is fast, secure, and reliable. From laptops to data


38

centres, game consoles to scientific supercomputers, mobile phones to the Internet, chatting

with people to viewing images in 3D; Java is everywhere!

And moreover …..

Java is free to download !!!!

It is available at http://www.java.com/en/

The main feathers of TurboWeb are:

You can download code/program over the internet

No installation procedure is involved

You can always have latest version of Turbowin

It can run on a variety of computers (e.g. Windows, Linux, Mac, Solaris)

Portability: TurboWeb is available and works on Windows, Solaris, and Linux

platforms. It is expected to be ported to other platforms.

Caching: Applications launched with TurboWeb are cached locally. Thus, an already-

downloaded TurboWin is launched on par with a traditionally installed TurboWin.

Maintainability: If TurboWin is updated, TurboWeb updates the locally cached

version at the application's next invocation.

Easy launching: TurboWeb allows applications to be launched independently of a

Web browser. The application can also be launched through desktop shortcuts,

making launching the Web-deployed application similar to launching a native

application.

Ability to work offline: Turbowin can be used in situations where launching through

the browser is inconvenient or impossible.

After installing JRE just. click on following link to run TurboWeb

http://www.knmi.nl/turbowin/webstart/turbowin_jws.jnlp

Computer will warn you “This type of file may harm your computer”. Just neglect it.

TurboWeb is free of spywares, and viruses. Computer will ask you option whether you

want to save this file or open.

http://www.java.com/en/

http://www.knmi.nl/turbowin/webstart/turbowin_jws.jnlp


39

For the first time you can save this file on your computer, say on desktop. one icon like

will appear. This is the link for TurboWeb. Double click on it and open TurboWeb ..

Now you are linked with Turbowin. Start recording weather observations.

The password for entering ship’s call sign and station data, will be

provided to individual ships on request, if email is sent to

[email protected] or [email protected] by authentic Indian

ship.

Back To Contents

mailto:[email protected]


40

3. BULLETINS AND WARNINGS

3.1 CATEGORIES OF BULLETINS AND WARNINGS

In this chapter, the procedures for the issue of various types of bulletins and

warnings by the Cyclone Warning Centres (ACWCs/ CWCs) will be described. The

bulletins and warnings may be divided into the following broad categories:

(1) Weather and Sea bulletins :

(a) for shipping on the high seas; and

(b) for ships plying in coastal waters

(2) Bulletins for Indian Navy

(3) Bulletins for departmental exchanges

(4) Port warnings

(5) Fisheries warnings

(6) Four Stage warnings

(7) Bulletins for A.I.R

(8) Warnings for Designated/Registered users (Album page warnings)

(9) Bulletins for Press

(10) Aviation warnings

3.2 WEATHER AND SEA BULLETINS

3.2.1 TYPES OF BULLETIN

These bulletins are of two types :

(a) Sea area bulletins for shipping on the high seas, and


41

(b) Coastal bulletins for ships plying in coastal waters. For the purpose of the second

type of bulletin, the coastal area is defined as the sea area upto 75 km off the coast

line.

TYPES OF BULLETINS AND WARNINGS

1. Sea Area bulletins

a) for shipping on high seas

b) for ships plying in coastal waters (up to 75 kms. off the coast line)

2. Bulletins for Indian Navy

3. Bulletins for departmental exchanges

4. Port warnings.

5. Fisheries warnings

6. Four stage warnings.

7. Bulletin for AIR

8. Warnings for Designated/Registered users.

9. Bulletins for Press

10. Aviation warnings

11.

Sea Area Bulletins for shipping on high seas

1.1 Office of Issue and broadcast by

For Bay of Bengal ACWC Kolkata, CRS, Kolkata (VWC) &CRS,

Chennai (VMM)

For Arabian Sea ACWC Mumbai, CRS, Mumbai (VWB)

For Arabian Sea and Bay of Bengal and for

Departmental exchanges Bay of Bengal

ACWC, Chennai


42

Contents of Daily Bulletins

Part I Storm Warning

Part II Synopsis of Met. Condition

Part III Forecast

Part IV Surface Analysis in IAC Fleet Code

Part V Ship Reports

Part VI Surface and U.A. Data

Bulletins of Kolkata and Mumbai contain all the six parts while same of Chennai contain

only Part I, Part II and Part III.

3.2.2 PORT WARNINGS

A uniform system of storm warning signals for ports introduced at all parts from 1st

April 1898 is still in vogue. It consists of

i) General System with eleven signals

ii) Extended systems with all the eleven signals plus six section signals. These are available

in the following ports only; Sagar Island, Kakinada, Chennai, Cuddalore and

Nagapattinam.

iii) Brief systems with five signals only viz Signal Nos III, IV, VII, X and XI. These ports are

frequented mainly by smaller vessels.

iv) Ports without Signals - These ports are treated as brief ports and get corresponding

warnings but are not to hoists signals.

Important points with regard to issuance of Port Warnings.

a) Time reference is in IST not in UTC


43

b) Positions of centres should be given both in Lat./Long. as well as distance and bearing

from well known port/place.

c) Central Pressure in hPa may be mentioned.

d) Number of signal to be given in plain language (Two, Three etc)

e) Words like ‘Keep signal Number Five hoisted’ may be used.

f) Messages may be sent by ‘XXV’ telegram.

For Danger/Great Danger signals ‘000 – weather Immediate’ messages to be sent. Trunk

call/STD may be used in emergent situation. Police W/T may also be used wherever

possible.

g) Because of uncertainty of storm movement, simultaneous hoisting of Danger/Great

Danger signals and LW-IV are allowed in different ports.


44


45

DESCRIPTIVE TERMINOLOGY FOR MONSOONS

10. In the weather forecast and meteorological bulletins for sea areas and coastal bulletins

issued by the Forecasting Officers of the India Meteorological Department during the South-

West and North-East Monsoon periods, the intensity of the monsoon is classified as weak,

moderate, etc., in terms of the wind speed over the sea area. The following specifications apply to

the description of the intensity of monsoon:-

Classification of Monsoon Corresponding wind speed

Weak Up to 12 Knots

Moderate 13 to 22 Knots

Strong 23 to 32 Knots

Vigorous 33 Knots and above.

3.2.3 LIST OF STORM SIGNAL STATIONS

1. List of Storm Signal Stations on the Indian Coast is given below.

Details of storm warning signals are given in the publication "Code of Storm Warning Signals"

issued by the Indian Meteorological Department.

INDIA - WEST COAST

General System Mandvi (kachchh), New Kandla, Navlakhi, Jamnagar (Bedi),

Okha, Porbander, Veravel, Mumbai, Mormugao, Karwar, Mangalore, Panambur

(New Mangalore), Calicut, Beypore, Cochin(Kochi) and Alleppey.

Brief System Jakhau, Mundra, Sikka, Salaya Dwarka (Rupen), Mangrol, Diu,


46

Madhwad, Navabander, Jafarabad, Rajula (Pipavav), Mahuva, Talaja, Gogha, Khambhat, Dahej,

Bharuch, Surat (Magdala), Bilimora, Valsad, Daman, Maroli, Umbergaon, Dahanu, Tarapur,

Nawapur (Boisar), Satpati, Kalve Mahim, Dantiware (Palghar), Arnala (Agashi), Bassein

(Vasai),Uttan (Bhayandar), Manori (Malad), Versova (Andheri), Bandra, Trombay, Thane,

Kalyan, Mora (Uran), Thal, Alibag, Revdanda, Murud (Janjira), Rajpuri, Shrivardhan, Bankot,

Harnai, Dabhol, Jaigad, Varoda (Malgund), Ratnagiri (Bhagawati Bunder), Purnagad,

Jaitapur, Vijaydurg, Devgad, Achara, Malvan, Nivti (pat), Vengurla, Redi, Kiranpani, Panaji

Honavar, Kasaragod, Bhatkal, Gangoli (Coondapoor), Malpe, Azhikal

Ports which receive information but hoist no

signal at present

Koteshwar, Pindhara, Bhagwa, Onjal, Wansi

Borsi, Umarsadi, Kolak, Ulwa, Belekeri

(Avarsa), Tadri (Gokram), Kumta,

Murdeshwar, Mahe, Kodungallur, and Vadinar

Note :- On receipt of warnings, the Port Officer at Gangoli (Coondapoor) transmits

suitable warnings to smaller ports of Hangarkotta and Bainduru which fall within his

jurisdication.

INDIA - EAST COAST

General System Tuticorin, Pamban, Pondicherry,

Nizamapatnam, Machilipatnam,

Vishakhapatnam, Gopalpur, Paradip, Diamond

Harbour, Budge Budge, Calcutta and Port Blair.

Brief System Kolachal, Kilakarai, Rameswaram,

Krishnapatnam, Vadarevu, Bhimunipatnam,

Kalingapatnam, Puri and Chandbali.


47

Extended System Nagapattinam, Cuddalore, Madras, Kakinada

and Sagar Island.

Ports which receive information but hoist no

signal at present

NIL

3.2.4 BULLETINS FOR INDIAN NAVY

Two types of bulletins for Indian navy

Since Naval Ships do not keep watch on commercial weather bulletins, separate weather bulletins for

broadcast to the ships of the Indian Navy are issued to the Naval W/T stations.

These bulletins are of two types

i) Those issued exclusively for broadcast to Indian Naval Ships, called the fleet

forecasts

ii) Those which are issued for merchant shipping and also sent for broadcast to Indian

Naval Ships, viz

a) coastal bulletins for Indian coastal areas.

b) Extra, Storm and Special sea area bulletins for Bay of Bengal and Arabian Sea.

Fleet Forecasts- Frequency and Areas of Responsibility

Fleet Forecasts are issued exclusively for broadcast to Indian Naval ships through

Naval W/T stations. They are issued twice daily, corresponding to Aurora and

Balloon sea area bulletins. The areas of responsibility for fleet forecasts are larger

than those for merchant shipping. In the forecast portion, the designation of the sea

areas used in the Fleet Forecasts are different from those used for merchant shipping,

the areas and sub areas are indicated by letters and numbers.

Offices of Issue of Fleet Forecasts


48

The offices which issue the Fleet forecasts and their areas of responsibility are given

below:

Office of issue Area of responsibility Sub-areas

ACWC Mumbai Arabian sea to the north of Latitude

50N and East of long. 60

0E, Gulf of

Oman and Persian Gulf

B 00, 20, 25, 30, 35, 40, 55

& E 00, 05

ACWC Kolkata Bay of Bengal and Andaman Sea to

the north of Lat. 50N

C 65, 70, 75, 80, 85 E 10 and

West half of E 15

INOSHAC, Pune Indian Ocean between Lat.50N and

100S and Long 60

0E to 100

0E

E 20, 25, 30, 35, 40, 45,50, 55,

60, 65, 70,75.

Items in Fleet Forecast

The Fleet Forecast is in plain language and contains the following items

I ) A brief general inference for the area. In the case of bay of Bengal and Arabian sea, the inference

will conform to the aurora and balloon bulletins issued by ACWCs Mumbai and Kolkata. However,

unlike the merchant shipping bulletins, the inference portion will not be divided into parts- I and II

and also will not include the identification prefixes such as aurora etc. But the type of warning-viz.-

cyclone warning etc. forming part of the message, will be included

II ) Forecast for the numbered sections of the area. The forecast will cover (a) surface wind (b)

visibility and (c) state of sea on certain occasions

III) An outlook for the next 12 hours.

Times of origin and broadcast

Fixed time of origin are given to the fleet forecast messages – 0800 UTC in the case of day bulletin

and 1700 UTC in the case of the night bulletin. However, the bulletins should be originated

sufficiently early to allow for their timely reception at RCC Mumbai. These fleet forecasts are

broadcast by Naval W/T station, Mumbai, during weather broadcast period commencing from 0930

UTC and 1830 UTC respectively.

Important instructions


49

The following are some of the important instructions that should be followed while framing the fleet

forecasts.

Forecasts to be brief

Fleet forecast messages should be brief. It should be borne in mind that the requirements of the

ships at sea are principally wind (direction and speed) and visibility and hence the area forecasts

must contain only these two elements and their variations. Weather is of importance only in so far

as visibility is affected, as for example by heavy rain; if no rain is forecasts or only light showers are

expected, no mention need be made of weather at all as visibility is not likely to be affected. State of

sea can be generally estimated from the wind speed; however, if it is likely to be different when

cyclone exists, reference should be made to the fact, for the sake of brevity; sections may be

combined wherever possible.

Wind speed and direction

Wind speed is given in knots and wind direction in eight point of compass ; Visibility and state of

sea will be given as follows.

Visibility:

Code Fig. Descriptive term In Km.

90 - 94 Very poor Less than 2

95 Poor 2 – 4

96 Moderate 4 – 10

97 Good 10 – 20

98 Very good 20 – 50

99 Excellent 50 or more

State of Sea :

State of Sea Wave Height

Calm (glassy) 0

Calm (rippled) 0 – 0.1


50

Smooth (wavelets) 0.1 – 0.5

Slight 0.5 – 1.25

Moderate 1.25 – 2.5

Rough 2.5 -4

Very rough 4 – 6

High 6 – 9

Very high 9 – 14

Phenomenal Over 14

Central pressure The central pressure will be given from storm surge upwards.

Validity The daily forecasts are valid for 12 hours from 1000 UTC

and 2200 UTC respectively

Outlook and ‘FOLC’ Outlook for next 12 hours in clear terms from the termination the forecast

period should be appended to both day and night bulletins as a routine. The preamble may be

Further outlook subsequent 12 hours etc. The abbreviation FOLC (Further Outlook – Little change

) can be used when no change is expected.

Modification to previous forecast

When weather conditions are reasonably stable, the evening forecast may be abbreviated with

reference to the previous morning forecast; for example, such of those sections where the evening

forecast is not different from the morning forecast, the phrase no modification……OR is as

from1000 UTC/ date for sections…may be used.

Mode of transmission of Fleet Forecast to Naval W/T Mumbai

ACWC Kolkata and INOSHAC Pune send their fleet Forecasts to RCC Mumbai through

departmental T/P channels. These Fleet Forecasts together with the one issued by ACWC Mumbai

are transmitted by RCC on T/P to Naval W/T station, Mumbai, through the Naval Met. Office,

Mumbai.

3.2.5 COASTAL BULLETINS


51

All the coastal bulletins (routine as well as non routine) issued by ACWCs/CWCs for Indian

Coastal areas will also be passed on to the Navy for broadcast. In normal weather, there will be only

two bulletins daily and the frequency will be increased to six times a day in the event of cyclonic

storms. The coastal bulletins for west coast are broadcast by Naval W/T station Mumbai and those

for east coast by Naval W/T station Visakhapatnam. The ACWCs/CWCs will address the coastal

bulletins to either the Naval W/T stations Mumbai or Visakhapatnam as given on next page:

Office of issue For coast Addressed to

ACWC

Mumbai

i)Goa

ii) Maharashtra

Naval W/T

Mumbai

CWC Ahmedabad i) Gujarat Naval W/T

Mumbai

ACWC Chennai i)Kerala

ii)Karnataka

iii)Tamil Nadu

Naval W/T

Mumbai

CWC Visakhapatnam i) Andhra Naval W/T

Mumbai

CWC Bhubaneshwar i) Orissa Naval W/T

Mumbai

ACWC

Kolkata

i)West Bengal

ii)Andman and Nicobar islands

Naval W/T

Mumbai

Extra, Storm and Special Sea Area Bulletins

Whenever extra, storm and Special Sea Area Bulletins are issued for merchant shipping during

disturbed weather for Arabian sea and Bay of Bengal by ACWC Mumbai and ACWC Kolkata

respectively, these are also sent to the Navy. While the above bulletins for Arabian sea issued by

ACWC Mumbai are passed onto Naval W/T station Mumbai for broadcast, similar bulletins (extra,

storm and special ) in respect of Bay of Bengal issued by ACWC Kolkata are sent to Naval W/T

station Kolkata.

Back To Contents

52

4. THE GLOBAL MARITIME DISTRESS AND SAFETY SYSTEM (GMDSS)

The GMDSS is specifically designed to automate a ship's radio distress alerting

function, which is the outcome of the International Convention for the Safety of Life At Sea

(the SOLAS Convention) with the oringin of the 1912 Titanic Disaster. The GMDSS applies

to vessels subject to the SOLAS Convention - that is: Commercial vessels of 300 Gross

Registered Tons (GRT) and above, engaged on international voyages. The GMDSS became

mandatory for such vessels as at February 1, 1999.

Prior to this implementation, the second session of the ad hoc group on the GMDSS

met at Meteo France, in Toulouse, September 14-18, 1999, to finalize plans and transmission

schedules. The maps of subdivisions of the Met areas and transmission schedule are given

aside. In November of 1997, a questionnaire was circulated to members of the International

Chamber of Shipping, ship owners and masters to obtain user feedback on meteorological

content of the GMDSS broadcasts. Of the 690 questionnaires returned, 625 were analyzed

with regard to the quality of warnings and forecasts issued for the Metareas.

Both the numerical analysis and a review of the comments indicated a very high

degree of user satisfaction with the meteorological content of GMDSS SafetyNET services.

Around 81% of the respondents indicated that for the Metareas they navigated the warnings

and forecasts were good, about 16% indicated they were fair, and around 3% indicated they

were poor. The ad hoc group found the questionnaire worthwhile and recommended that

another one be undertaken in about 2 years. Mr. M. Ziemianski (Poland) successfully

undertook the difficult task to develop guidelines for NAVTEX broadcasts in the Baltic Sea.

While the guidelines will be submitted to RA VI and CMM for formal adoption, it is urged

that operational implementation not be delayed following the formal agreement by the

Permanent Representatives concerned. The ad hoc group considered other areas where

requirements may exist for international coordination of forecasts and warnings broadcast

through NAVTEX. It was generally noted that such coordination was already taking place, or

plans existed to move towards this coordination. Several substantive amendments to the

WMO Regulations related to GMDSS are proposed for consideration of CMM-XIII/JCOMM-

I.

For the safety Net Met. Area VIII (N) issues daily two GMDSS bulletins are issued in

fair weather. In disturbed weather (cyclones etc) extra bulletins are issued every three hours.

These bulletins are issued from the INOSHAC Section of Office of DDGM (WF), Pune and


53

transmitted to DGM (Telecom) New Delhi through NHAC New Delhi for its onward

transmission on Global Channel through Land Earth Station (LES) Arvi via

IMARSAT/NAVTEX.

The bulletins comprise 24 hour forecast of following parameters

1. Wind speed and Direction 2. Weather 3. Visibility and 4. State of Sea

The bulletins are issued twice a day at 0900 and 1800 UTC

With effect from 1 September 2009, the bulletins are issued with a validity period of 24 and

48 hours. Visibility and State of sea are expressed in Nautical Miles and Wave height in

meters


54

4.1 MARINE POLLUTION EMERGENCY RESPONSE SUPPORT SYSTEM FOR THE HIGH SEAS

MPERSS's primary objective is to have in place a coordinated, global system for the

provision of meteorological and oceanographic information for marine pollution emergency

response operations outside waters under national jurisdiction. The areas covered have the

same geographical distribution than those for the GMDSS and Area Meteorological

Coordinators have been identified for all of them.

Area Meteorological and Oceanographic Coordinator:

An Area Meteorological and Oceanographic Coordinator (AMOC) is a national service which may

be

- National Meteorological Service, or

- National Meteorological Service which also operates oceanographic services, or

- National Meteorological Service keeping liaison with Oceanographic Service(s) where these

are in operation which has accepted responsibility for coordinating the provision of regional

meteorological information and oceanographic information as appropriate, which is issued to

support marine pollution emergency response operations in the designated area for which the

Service (or Services) has accepted responsibility. The AMOC is also available to provide relevant

support and advice for waters under national jurisdiction within its area if so requested by the

countries concerned. [These national Services may eventually become designated Regional

Specialized Centers for Marine Pollution Emergency Support.]

The issued information may have been prepared solely by the AMOC, or by another Supporting

Service(s), or a combination of both, on the basis of an agreement between the Services

concerned. The location and contact (telephone, e-mail, telex, telefax, etc.) details of any marine

pollution emergency response operations authority (or authorities) responsible within the

designated Marine Pollution Incident (MPI) are should be maintained on the MPERSS web site.

National information for this site should be maintained by AMOCs or Supporting Services.


55

The support supplied by an AMOC (or a Supporting Service) shall include:

(a) Basic meteorological forecasts and warnings tailored for the area(s) concerned;

The support supplied by an AMOC (or a Supporting Service) may also include:

(b) Basic oceanographic forecasts for the area(s) concerned

(c) The observation, analysis and forecasting of the values of specific meteorological and

oceanographic variables required as input to models describing the movement, dispersion,

dissipation and dissolution of marine pollution;

(d) In some cases, the operation of these models;

(e) In some cases, access to national and international telecommunications facilities;

(f) Other operational support.

Back To Contents


56

5. SHIP WEATHER CODE OBSERVATION CODE, FM 13-IX SHIP

5.1 SHIP SURFACE OBSERVATION CODE FORMAT

Like the synoptic surface observation code for land stations, the ship

surface observation report is transmitted at 6-hourly intervals at the standard hours of

observation which are: 0000, 0600, 1200, and 1800 UTC.

The following shows the symbolic form of the message for the synoptic weather report from a ship station.

A. SYMBOLIC FORM OF THE MESSAGE

FM 13-VII SHIP – Report of surface observation from a

sea station. C O D E F O R M (D. . . D)

SECTION 0 MiMiMjMj ( A1bwnbnbnb) YYGGiw 99LaLaLa

QcLoLoLoLo

SECTION 1 iR iXh VV Nddff 1snTTT 2snTdTdTd 3PoPoPoPo**

4PPPP 5appp 6RRRtR** 7wwW1W2 8NhCLCMCH

9hh//**

SECTION 2 222DsVs (0snTwTwT w)

(1PwaPwaHwaHwa)** (2PwPwHwHw) ((3dw1dw1dw2dw2)

(4Pw1Pw1Hw1Hw1) (5Pw2Pw2Hw2Hw2)) (6IsEsEsRs)

(ICE+Plain language

or ciSibiDiZi )


57

SECTION 3 333

(0 . . . . ) (1snTxTxTx) (2snTnTnTn) (3Ej j j)

(4E’sss) (5j1j2j3j4) (6RRRtR) (7 .

. . .) (8NsChshs) **

(9SpSpSpSp) (80000 ) (0 . . . .) (1 .. .

.)

SECTION 4 444

SECTION

5

N’C’H’H’Ct **

555 Groups required as per national practice. *

** Not to be reported by ships

5.2 DEFINITION OF GROUPS

1. Section 1

MiMiMjMj- Bulletin Header

This group identifies the bulletin as a collection of marine observations. In a collection of ship, manned buoys, or automatic buoys, the group will be encoded as BBXX and will be the first line of the bulletin. This group is attached at the collection center where the bulletin is prepared.

DDDD - Ship International Call Sign. This is a four letter code which is assigned to each ship. The first two letters identifies the ship's country of registry.


58

YYGGiw - Observation Time and Wind Indicator Group. Unlike the land

observation bulletins where the date/time group is pulled out of the report and is placed after the bulletin header, this group remains with the ship report following the ship call sign. Thus, in a bulletin of ship reports there may be one report from one time and another report from a different time. When looking at a bulletin of ship reports, be certain to look at the date/time group to know when the observation was taken.

YY - Day of the month (UTC) on which the observation was taken. GG

- Time of the observation in UTC to the nearest whole

hour.

iw - Wind speed indicator. See table 1855.


59

Code table 1855 iw — Wind speed indicator

Code

figure

Description

0 Wind speed estimated, reported in

meters per second.

1 Wind speed obtained from anemometer,

reported in mps

3 Wind speed estimated, reported in knots.

4 Wind speed obtained from anemometer,

reported in knots.

/ Wind speed not available

60

99LaLaLa - Ship Latitude Group

99 - Identifier for the ship latitude group. LaLaLa

- Latitude in tenths of degrees.

QcLoLoLoLo - Ship Longitude Group

Qc - Quadrant of the globe in which the ship is located. See code table 3333 and figure 1.

Code table 3333 Qc — Quadrant of the globe

Code

figure

Latitude,Longitude

1 North East

3 South East

5 South West

7 North West

61

LoLoLoLo - Longitude in tenths of degrees.

iRiXhVV - Precipitation Indicator, Type Station, Lowest Cloud

Height and Visibility Group.

iR - Indicator for inclusion or omission of precipitation data. See

code table 1819 of the land station synoptic code.

iX - Indicator for the type of station operation and whether group 7

is encoded in section 1. See code table 1860 of the land

synoptic code.

h - Height above sea level of the base of the lowest cloud seen. Use code table 1600 of the land station synoptic code.

VV - Horizontal surface visibility. Use groups 90 — 99 of code table

4377 as given below.

Code table 4377 VV — Abbreviated

for ship visibility codes

Code

figure Statute

miles

Kilometers 90 <1/16 <0.05 91 1/1

6 0.05

92 1/8 0.2 93 1/4 0.5 94 1/2 1 95 1 or 11/2 2 96 2, 21/2, or 3 4 97 5, 6, 7, or 8 10 98 9 or 10 20 99 not reported not reported

Nddff - Cloud Cover and Wind Group.


62

N - Total cloud amount in oktas. See code table 2700 of the land station synoptic code.

dd - True wind direction in tens of degrees. Use code table 0877 of the land station synoptic code.

ff - Wind speed . Units of wind speed are indicated by the value for iw. When the wind speed, in units indicated by iw,

is 99 units or more, ff shall be encoded 99, and the group 00fff shall be included immediately following the group Nddff.

1snTTT - Surface Air Temperature Group.

1 - Identifier for the air temperature group.

sn - Sign of the temperature;

0 = temperature is positive or zero; 1 =temperature is negative.

TTT - Surface air temperature in tenths of degrees Celsius.

2snTdTdTd - Dew Point Temperature Group.

2 - Identifier for the dew point temperature group.

sn - Sign of the dew-point temperature; 0 = positive or zero; 1 =

negative, 9 = Relative humidity reported instead of dew point.

TdTdTd - Dew-point temperature reported in tenths of

degrees Celsius.

UUU - Relative humidity of the air, in per cent, the first figure being zeroexcept for UUU = 100 per cent. Relative humidity is reported in place of TdTdTd if dew point temperature is unavailable. Every effort should be made to convert relative humidity to a dew point temperature.

4PPPP - Sea-Level Pressure Group.

4 - Identifier for the sea-level pressure group.

PPPP -Sea-level pressure reported to the nearest tenths of hectopascal. If the sea-level pressure is more than 999.9 hectopascals, drop the thousands value of the pressure. Note: the station pressure,


63

group3, is not encoded since the station pressure and sea-level pressure are the same.

5appp - 3-Hour Pressure Tendency and Change Group.

5 - Identifier for the three-hour pressure tendency and pressure change group.

a - Characteristic of the pressure tendency during the three hours preceding the time of the observation. Use code table 0200 of the land station synoptic code.

ppp - Actual change in the pressure during the three hours ending at the actual time of the observation, in tenths of hectopascals.

7wwW1W2 - Present and Past Weather Group

7 - Identifier for the present and past weather group.

ww - Present weather at the time of the observation. Use code table 4677. Code table 4677 is the present weather symbol table. The two-digit number identifying the most significant present weather is encoded for ww.

W1W2 - The most significant and the second most significant past weather

during the period. In general, and together will cover a maximum of three or six hours and will be different code figures. See code table 4561 of the land station synoptic code. For primary reports sent at the main synoptic times, the past weather covers the last six hours. For intermediate synoptic reports, the period covers the last three hours.

8NhCLCMCH- Cloud Type Group

8 - Identifier for the cloud group.

Nh - The total amount of CL,or, if no low clouds, the total amount o f

CM clouds. Use code table 2700 as found in the Nddff group of

the land station synoptic code.

CLCMCH - Principal types of low, middle, and high clouds. See code tables

0513, 0515, and 0509 respectively as found in the land station synoptic code.


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9GGgg - Actual Time of Observation Group

9 - Identifier for actual time of observation group.

GG- Hour, in UTC, of actual observation time.gg -

Minute, in UTC, of actual observation time.

NOTE: in WMO Region IV and V, this group is included as 9YYGG, the day of the month and hour UTC of the observation, a redundant reporting of the day and hour as found in the YYGGiw group.

2. Section 2.

222DsVs - Section 2 Identifier and Ship Movement Group

222 - Identifier of Section 2.

Ds - Direction of ship movement made good during the previous three

hours. Encode using the code table 0700 in the land station synoptic code.

0 = Calm

1 = Northeast 5 = Southwest

2 = East 6 = West

3 = Southeast 7 = Northwest

4 = South 8 = North


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Vs - Speed of the ship made good during the previous three hours.

Encode using code table 4451.

Code figure speed knots speed km/hour

0 0 0

1 1-5 1-10

2 6-10 11-19

3 11-15 20-28

4 16-20 29-37

5 21-25 38-47

6 26-30 48-56

7 31-35 57-65

8 36-40 66-75

9 over 40 over 75

/ Report from a coastal land station

or not reported

.

0snTwTwTw- Sea-Water Temperature Group

0 - Identifier for sea water temperature group.

sn - Sign of the temperature; 0 = positive or zero; 1 = negative. TwTwTw-

Sea-water temperature in tenths of degrees Celsius.

1PwaPwaHwaHwa - Instrumental Wave Data Group

1 - identifier for the instrumental wave data group. PwaPwa -

Period of wind waves in whole seconds. HwaHwa

Height of wind waves in units of half-meters.

2PwPwHwHw - Wind-Wave Group

2 - Identifier for the wind-wave group. This group is used when instrumental wave data are not available and the period and


66

height of wind waves are estimated.

PwPw - Period of the wind wave in whole seconds.

HwHw - Height of the wind waves in units of half-meters. The

wave height reported in code form is the significant wave height. See the land station synoptic code for the code figures used to report height values.

3dw1dw1dw2dw2 - Swell Wave Direction Group

3 - Identifier for the swell wave direction group.

dw1dw1 - The true direction, in tens of degrees, from which the first swell

wave system is moving.

dw2dw2 - The true direction, in tens of degrees, from which the second

swell wave system is moving.

4Pw1Pw1Hw1Hw1 - First Swell System Group

4 - Identifier for the first swell system group.

Pw1Pw1 - Period of the first swell system in whole seconds.

Hw1Hw1 -Average height of the significant swell waves of the first swell

system reported in half meters.

5Pw2Pw2Hw2Hw2 - Second Swell Wave System Group

5 - Identifier for the second swell wave system group.

Pw2Pw2 - Period of the second swell wave system in whole seconds.

Hw2Hw2 -Average height of the significant swell waves of the second swell

system.


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6IsEsEsRs - Ship Ice Accretion Group

6 - Identifier for the ship ice accretion group

Is - Ice accretion code. See code table 1751

EsEs - Thickness of ice accretion on ship in centimeters.

Rs - Rate of ice accretion. See code table 3551.

Code table 1751 Is - Ice accretion on ships

Code

figure

Description

1 Icing from ocean spray

2 Icing from fog

3 Icing from spray and fog

4 Icing from rain

5 Icing from spray and rain

Code table 3551 Rs — Rate of ice accretion on ships

Code figure Description

0 Ice not building up

1 Ice building up slowly.

2 Ice building up rapidly

3 Ice melting or breaking up slowly

4 Ice melting or breaking up rapidly.


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70HwaHwaHwa - Instrumental Wave Height Group

70 - Identifier for the instrumental wave height group. This group shall be reported in addition to the group 1PwaPwaHwaHwa when the sea is not calm, HwaHwa has not been reported as

// and the station has the capability of accurately measuring instrumental wave height in units of 0.1 meters.

HwaHwaHwa - Height of instrumetal measured waves to the nearest 0.1 meters.

8swTbTbTb - Wet-bulb Temperature Group

8 - Identifier for the wet-bulb temperature group. When the wet bulb is used to derive the dew-point value, this group will be included to report the wet-bulb temperature.

sw - Sign of the wet-bulb temperature: 0 = positive, 1 = negative.

TbTbTb - Wet-bulb temperature to the nearest tenth of a degree Celsius.

ICE ciSibiDizi- Sea Ice Information Group. This group is used for the reporting of

sea ice of either sea or land origin.

ICE - Identifier that sea ice information follows.

ciSibiDizi - Sea ice information

ci - Concentration or arrangement of sea ice. See code table 0639.

Si - Stage of development of the sea ice at the time of the observation.

See code table 3739.

bi - Ice of land origin present at time of observation. See code table

0439.


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Di - Orientation of the principal edge of the sea ice at the time of the

observation. See code table 0739.

zi - Present ice situation and trend of conditions over preceding 3 hours. See code table 5239.

Code table 0639 ci — Ice concentration

Code

figure

Description

0 No sea ice in sight

1 Ship in open lead more than 1.0 nautical mile wide, or ship in fast ice with boundary beyond limit of visibility

2 Open water or very open pack ice,<3/10 concentration.*

3 Open pack ice 4/10 to <6/10 concentration.*

4 Close pack ice 7/10 to <8/10 concentration.*

5 Very close pack ice 9/10 or more, but not 10/10 concentration

6 Strips and patches of pack ice with open water between.*

7 Strips and patches of close or very close pack ice with areas of lesser concentration

between.*

8 Fast ice with open water, very open or open pack ice to seaward of the ice

boundary.*

9 Fast ice with close or very close pack ice to seaward of the ice boundary.*

/ Unable to report, because of darkness, poor visibility or because ship is more than

0.5 n mile away from ice edge.


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Code Table 3739 Si — Stage of development of sea ice


0 New ice only (frazil ice, grease ice, slush, shuga).

1 Nilas or ice rind, less than 10 cm thick.

2 Young ice (gray ice, gray-white ice), 10 to 30 cm thick.

3 Predominantly new and/or young ice with some first-year ice.

4 Predominantly thin, first-year ice with some new and/or young ice.

5 All thin, first-year ice (30 to 70 cm thick.)

6 Predominantly medium first-year ice (70 to 120 cm thick) and thick, first-year ice (greater than 120 cm thick) with some thinner (young) first-year ice.

7 All medium and thick first-year ice.

8 Predominantly medium and thick, first-year ice with some old ice (usually more than 2 meters thick.)

9 Predominantly old ice.

/ Unable to report because of darkness, low visibility, only ice of land origin is visible, or because the ship is more than 0.5 nautical miles away from the ice edge.

Code table bi — Ice of land origin (0439)

Code Fig Descriptions

0 No ice of land origin.

1 1-5 icebergs, no growlers or bergy bits.




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4 Up to and including 10 growlers and bergy bits, no icebergs.

5 More than 10 growlers and bergy bits, no icebergs.

6 1-5 icebergs with growlers and bergy bits.



9 More than 20 icebergs with growlers and bergy bits, a major hazard to navigation.

/ Unable to report because of darkness, low visibility, or only sea ice is visible.

Code Table Di- True bearing of Principle Ice


0 Ship in shore or flaw lead.

1 Principal ice edge towards NE.

2 Principal ice edge towards E.

3 Principal ice edge towards SE.

4 Principal ice edge towards S.

5 Principal ice edge towards SW.

6 Principal ice edge towards W.

7 Principal ice edge towards NW.

8 Principal ice edge towards N.

9 Not determined. Ship in ice.

/ Unable to report because of darkness, low

visibility, or only ice of land origin is visible.


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Code Table Zi- Ice situation and trend over preceding three hours

Code Description

0 Ship in open water with floating ice in sight.

1 Ship in easily penetrable ice; conditions improving.*

2 Ship in easily penetrable ice; conditions not changing.*

3 Ship in easily penetrable ice; conditions worsening.*

4 Ship in ice difficult to penetrate; conditions improving.*

5 Ship in ice difficult to penetrate; conditions not changing.*

6-9 Ice difficult to penetrate, conditions worsening.

6 Ice forming and floes freezing together.*

7 Ice under slight pressure.*

8 Ice under moderate or severe pressure.*

9 Ship beset.*

/ Unable to report, because of darkness or poor visibility.

(* Ship in ice)

Back To Contents

73

6. DRIFTING BUOY COOPERATION PANEL (DBCP)

The Drifting Buoy Cooperation Panel (DBCP) is composed of national networks

of moored and drifting buoys. Several of these data buoy networks have been

identified as elements of the Global Ocean Observing System (GOOS), Integrated

Observing System. DBCP also encourages, supports, or initiates development and

testing of new observing techniques, quality control procedures, and new data

processing systems. It also encourages impact studies based on buoy data.

The most important task of the DBCP is to ensure a satisfactory

coordination at the international level of drifting and moored buoy programs to

increase the number of buoys deployed, rationalize spatial distributions for most

effective data returns, and continually improve data quality.

These measurements are obtained as part of an international program

designed to make this data available in an effort to improve climate prediction.

Climate prediction models require accurate estimates of SST to initialize their

ocean component. Drifting buoys provide essential ground truth SST data for this

purpose. The models also require validation by comparison with independent data

sets. Surface velocity measurements are used for this validation.

6.1 NATIONAL DATA BUOY PROGRAM

India with a coastline of over 7500 km length and about 2.02 million sq km

area within the Exclusive Economic Zone (EEZ) offers immense scope for exploration

and capitalization of marine resources. With this as a prominent aspect,

Department of Ocean Development, Government ofIndia has established the National

Data Buoy Programme (NDBP) in 1997 at the National Institute.

The Institute is firm to do systematic real-time meteorological and

oceanographic observations that are necessary to improve oceanographic services


74

and predictive capability of short and long-term climatic changes. Time series

observations are vital to improve the understanding of ocean dynamics and its

variability. A network of twelve data buoys have been deployed both in Arabian

Sea and Bay of Bengal during the implementation period of the programme from

1997 to 2002. The network has been presently increased to twenty.

6.2 FORMAT FOR BUOY DATA EXCHANGE

Mi Mi Mj Mj Y Y M M J G G g g iw

Qc La La La La La Lo Lo Lo Lo

Lo Lo

111 0 d d f f 1 Sn T T T 4 P P P P 222 0 Sn Tw

Tw Tw Pwa Pwa Hwa

Hwa

EXPLANATION:

Mi Mi Mj Mj Will always by ZZyy as per international practice

YY The day of the year

MM The month of the year

J The unit digit of the year

GGgg Time (UTC) in hours and minutes

iw Indicator group for reporting of wind observation (iw

= l in this case)

Qc Quadrant of the globe (Qc = l in this

case) La La La La La Latitude in thousands of a degree

Lo Lo Lo Lo Lo Lo Longitude in thousands of a


75

degree ddff Wind direction and speed

Sn Sign of Temperature (0 for +ve, l for –ve (Sn=0 in

this case) TTT Air temperature in tenths of degree

PPPP Pressure at mean sea level in tenths of hPa

(Thousand’s digit is omitted)

TW TW TW Water temperature in tenths of degree

Pwa Pwa Period of wind wave in seconds

Hwa Hwa Height of wind wave in units of 0.5 metres

6.3 FM 18-X BUOY – REPORT OF A BUOY OBSERVATION

76

NOTES:

(1) BUOY is the name of the code for reporting buoy observations.

(2) A BUOY report, or a bulletin of BUOY reports, is identified by the group MiMiMjMj

= ZZYY. (3) The inclusion of the group 9idZdZdZd is strongly recommended for

buoys which have been deployed with drogues.

(4) The group 9idZdZdZd should not be used in reports from a buoy on which

a drogue has never been installed.

(5) The code form is divided into five sections, the first beig mandatory in its entirety, except

group 6QiQt//, and the remainder optional as data are available:

Section

number

0 -- Identification, time and position data

1 111 Meteorological and other non-marine data

2 222 Surface marine data

3 333 Temperatures; salinity and current (when

available) at selected depths

4 444 Information on engineering and technical

parameters, including quality control data


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6.4 REGULATIONS FOR BUOY OBSERVATION REPORTING

6.4.1 GENERAL

The code name BUOY shall not be included in the report.

6.4.2 SECTION 0

6.4.2.1 All groups in Section 0 are mandatory, except group 6QiQt//, and shall be

included in each report, even if no other data are reported.

6.4.2.2 Each individual BUOY report, even if included in a bulletin of such report,

shall contain as the first group the identification group MiMiMjMj.

6.4.2.3 Group A1bwnbnbnb

Only buoy numbers (nbnbnb) 001 through 499 are assigned. In the case of a

drifting buoy, 500 shall be added to the original nbnbnb number.

NOTES:

(1) A1bw normally corresponds to the maritime zone in which the buoy was

deployed. The WMO Secretariat allocates to Members, who request and


78

indicate the maritime zone(s) of interest, a block or blocks of serial numbers

(nbnbnb) to be used by their environmental buoy stations.

(2) The Member concerned registers with the WMO Secretariat the serial numbers

actually assigned to individual stations together with their geographical positions of

deployment.

(3) The Secretariat informs all concerned of the allocation of serial numbers and

registrations made by individual Members.

6.4.2.4 Groups QcLaLaLaLaLa LoLoLoLoLoLo

Position shall be reported in tenths, hundredths or thousandths of a degree,

depending on the capability of the positioning system. When the position is in

tenths of a degree, the groups shall be encoded as QcLaLaLa// LoLoLoLo//.

When the position is in hundredths of a degree, the groups shall be

encoded as QcLaLaLaLa/ LoLoLoLoLo/.

6.4.2.5 Group (6QiQt//)

QiQt are quality control indicators. Qi applies to position

and Qt to time.

6.4.3 SECTION 1

6.4.3.1 Each of the groups in Section 1 shall be included for all parameters

that have been measured, when data are available.


79

6.4.3.2 When data are missing for all groups, the entire section shall be omitted from the report.

6.4.3.3 Group 111QdQx

Qd is a quality control indicator for the section. If all data groups have the

same quality control flag value, Qd shall be coded with that value and Qx

shall be set to 9. If only one data group in the section has a quality control flag

other than 1, Qd shall be coded with that flag and Qx shall indicate the

position of this group within the section. If more than one data group have a

quality control flag greater than 1, Qd shall be set to the greater flag value and

Qx shall be set to 9.

NOTE: When Qx shows the position of the data group, it should be relative to the

group containing Qx.

For example, Qx = 1 refers to the data group

immediately following.

6.4.4 SECTION 2

6.4.4.1 Each of the groups in Section 2 shall be included for all parameters

that have been measured, when data are available.

6.4.4.2 When data are missing for all groups, the entire section shall be omitted from the report.

6.4.4.3 Group 222QdQx


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Regulation 18.3.3 shall apply.

6.4.5 SECTION 3

6.4.5.1 GENERAL

Section 3 is in two parts. The first par, identified by the indicator group

8887k2, shall be used to report temperatures and/ or salinity at selected

depths. The second part, identified by the indicator group 66k69k3, shall be

used to report current at selected depths. Either or both parts shall be

transmitted, depending on the availability of the temperature and/ or salinity

data for the first part and of the current data for the second part.

6.4.5.2 Temperatures shall be reported in hundredths of a degree Celsius. When

accuracy is limited to tenths of a degree, data shall be encoded using the

general from 3TnTnTn/.

6.4.5.3 Group 333Qd1Qd2

Qd1Qd2 are two q u a l i t y control indicators. Qd1 is used to indicate

the quality of the temperature and salinity profile and Qd2 is used to

indicate the quality of the current speed and direction profile.

6.4.6 SECTION 4


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6.4.6.1 GENERAL

Additional groups in this section shall be included as data are available or required..

6.4.6.2 Group (1QpQ2QtwQ4)

When 1Qp , Q2, Qtw and Q4 = 0, the corresponding group shall not be

transmitted. Its absence thus indicates a satisfactory general operation.

6.4.6.3 Group (2QNQL//)

When QN and QL = 0, the corresponding group shall not be transmitted.

6.4.6.4 Group (QcLaLaLaLa)

This group shall be transmitted only whn QL = 2 (location over one pass

only). It gives the latitude of the second possible solution (symmetrical to the

satellite subtrack).

NOTE: Same coding as in Section 0.

6.4.6.5 Group (LoLoLoLoLoLo)

This group shall be transmitted only when QL = 2 and it gives the longitude of

the second possible position, the latitude being indicated by the previous

group.


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NOTE: Same coding as in Section 0.

6.4.6.6 Group (YYMMJ GGgg/)

The groups YYMMJ GGgg/ give the exact time of the last known position and

shall be transmitted only when QL = 1 together with the following group

7VBVBdBdB.

6.4.6.7 Group (7VBVBdBdB)

This group shall be transmitted only when QL = 1.

Example: At the last location, the true direction of the buoy is 47O and its

speed is 13 cm. s-1 – the group is coded 71304.

6.4.6.8 Group (8ViViViVi)

The number of groups 8ViViViVi containing information on the engineering

status of the buoy shall not exceed three.

NOTES:

(1) The physical equivalent of the value ViViViVi will be different from one buoy

to other

Back To Contents

83

7.MEASUREMENT OF METEOROLOGICAL PARAMETERS

7.1 GENERAL

Meteorological observations are made for a variety of reasons. They are used for the real-time preparation of weather analyses, forecasts and severe weather warnings, for the study of climate, for local weather dependent operations (for example, local aerodrome flying operations, construction work on land and at sea), for hydrology and agricultural meteorology, and for research in meteorology and climatology.

7.2 WIND INSTRUMENTS

7.2.1 ANEMOMETER

Anemometers have as yet found only limited use at sea, the chief problem being to achieve a suitable exposure. Estimation of wind force and direction from careful observation of the sea state is the method preferred. The ship disturbs the airflow in its vicinity with the result that the wind measured by the instrument is not representative of the true airflow over the open sea. If a portable cup-anemometer is used, the exposure may be varied at will and the best position chosen for any particular wind direction. The instrument measures 'apparent' wind speed. To determine the true value, the wind direction must first be estimated and then allowance made for the speed of the ship.

Anemometer consists of cups rotatable about a vertical shaft or a propeller rotating about a horizontal shaft. When driven by the wind at a speed proportional to wind force, the rotating shaft drives an electrical generator whose output is itself proportional to the speed of rotation. A voltmeter may thus be calibrated as wind speed. Anemometers are not normally used aboard merchant ships because of the difficulty of finding a suitable site and also because of expense. The UK Ocean Weather Ship carries anemometers on the yardarms at a suitable height above the water (23m), which seems to be the site furthest from eddying effects. But even here estimates of wind force and


84

direction from the appearance of the sea are regularly made as a check on the instruments

7.2.2 HAND ANEMOMETER

Whilst estimates of wind force and direction made on merchant ships by observations of sea state are to be considered the norm, a hand-held anemometer can be used for verification or in sheltered waters where the appearance of the sea may be modified by topographic features. The hand anemometer is held with its axis vertical, at arm's length, with the arm at right angles to the wind direction to avoid disturbance of the airflow by the observer's body. At least two readings of mean wind speed need to be taken within the overall period of observation, each reading being taken over at least 15 seconds. The wind speed is shown by a graduated scale across which a pointer moves. Hand anemometers are calibrated in knots over a range of 0 to 60.

7.2.3 DIGITAL HAND ANEMOMETER

This is similar to the hand anemometer except that the speed sensing mechanism does not make use of switched contacts. After sampling for 15 seconds the instrument displays the average wind speed digitally for a further period of 10 seconds. The body and switch of the anemometer are waterproof and support legs fixed to the body protect the cups against damage when the instrument is laid down. The power is supplied by battery with an indication when battery voltage is low.


85

Digital hand held anemometer

7.2.4 WIND VANE

The wind direction may be directly observed by the position of the wind vane or remotely read at deck level by an electrical direction transmitter known as a Magslip for mains power or a Desynn in the case of a battery system operated through gear wheels and a countershaft. Both types may be joined to an anemometer unit so that the two instruments form a single transmitting head.


86

7.3 ANEROID BAROMETER

In general the aneroid barometer should be set to read the pressure at the level of the instrument. On board ships and at fixed sea stations (rig, platform) however, the instrument may be set to indicate the pressure at Mean Sea Level, provided the difference between the station pressure and the Mean Sea Level pressure can be regarded as constant. The reading should be corrected for instrumental errors. If the pressure reading is not indicating the pressure at Mean Sea Level this program will correct the (instrument error corrected) reading to Mean Sea Level. The computed and automatically applied Height Correction (sometimes called altitude correction or reduction constant) depends on the information provided by the observer


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Aneroid barometer

7.3.1 MARINE BAROGRAPH

The amount of the pressure tendency and characteristic of the pressure tendency in the past three hours is obtained from a marine barograph, preferably an open-scale instrument graduated in divisions of 1 hPa, or from an integrated electronic barometer-barograph with a digital output.

Marine barograph


88

7.4 WHIRLING PSYCHROMETERS OR SLING PSYCHROMETERS

The wick (free of grease and not contaminated by salt spray) must be moistened with distilled water, if this is not readily available, water from the condenser will generally be more suitable than ordinary fresh water. For preference the psychrometer observation is made to the windward side. Whirling or rotating the thermometers by hand at a controlled rate ensures the ventilation. Sling psychrometers lacking radiation shields for the thermometer bulbs should be shielded from direct insolation in some other way. Thermometers should be read at once after aspiration ceases because the wet-bulb temperature will begin to rise immediately, and the thermometers are likely to be subject to insolation effects. The wick should be changed regularly.


89

Whirling psychrometers

7.4.1 LOUVERED SCREEN

If a louvered screen is to be used, two should be provided, one secured on each side of the vessel, so that the observation can always be made to the windward side. In this way the thermometers can be completely exposed to the air stream and uninfluenced by artificial sources of heat and water vapor. As an alternative, a portable louvered screen can be used, being hung on whichever side is to windward, to gain the same exposure. The muslin and wick fitted to a wet-bulb thermometer in a louvered screen should be changed at least once a week and more often if it becomes dirty or contaminated by salt spray, if any spray has reached the instrument, the muslin and wick should be replaced by new ones. It is advisable to do this in any case after bad weather.


90

Dew-point and relative humidity can be obtained from the readings of the air temperature (dry- bulb) and wet-bulb. If the wet-bulb reading is not available, dew-point and wet-bulb temperature can be obtained from the readings of the air temperature and relative humidity (if available)


91

During frost, when the muslin is thinly coated with ice, the readings are still valid because evaporation takes place from a surface of ice as freely as from one of water. If the muslin is dry it must be given an ice coating by wetting it slightly with ice-cold water, using a camel-hair brush or by other means. The water will usually take 10 to 15 minutes to freeze. Excess of water must not be used as it takes much longer to freeze and will also not give accurate readings. After the wetting of the muslin, the temperature generally remains steady at 0 °C until all the water has been converted to ice. It then begins to fall gradually to the true ice-bulb reading.

No reading must be recorded until the temperature of the ice-bulb has fallen below of the dry-bulb and remains steady. Dry, windy weather may cause the ice to evaporate completely before the time of the next reading, in which case the procedure of wetting the bulb must be gone through again. The original coating of ice will give satisfactory results as long it lasts. It must be pointed out that super cooled water may exist on the wet-bulb at temperatures well below freezing point and that, if this is not noticed by the observer, serious errors will occur. The freezing can be started by touching the wet-bulb with a snow crystal, a pencil, or other object.

7.4.2 SEA-SURFACE TEMPERATURE

The temperature to be observed is that of the sea surface representative of conditions in the near-surface mixing layer underlying the ocean skin.

The sea-surface temperature should be very carefully observed. This is because, amongst other things, it is used to obtain the difference with air temperature, which provides a measure of the stratification of temperature and humidity and of other characteristics of the lower layers of maritime air masses. For these reasons the temperature of a seawater thermometer should be read to 0.1 °C.

7.4.2.1 METHODS OF OBSERVATION OF SEA-SURFACE TEMPERATURE


92

It has not been possible to adopt a standard device for observing sea surface temperatures on account of the great diversity in ship size and speed and of considerations of cost, ease of operation and maintenance. The temperature of the sea surface may be observed by:

a) Taking a sample of the sea-surface water with a specially designed sea-bucket.

b) Reading the temperature of the condenser intake water.

c) Exposing an electrical thermometer to the seawater temperature either directly or trough the hull.

d) Other.

The principal methods used for very many years have been (a) and (b). Studies of difference in temperature provided by the two methods have been made in which it is reported that intake temperatures average 0.3 °C greater than those measured by sea-bucket samples. As the speed and height of ships have increased, method (c) which gives the most consistent results has been more widely used. Of all these methods the condenser intake technique is the least desirable because of the very great care needed to obtain good results.

7.4.2.2 SEA-BUCKET

A sea-bucket is lowered over the side of the ship, a sample of seawater is hauled on board and a thermometer is then used to obtain its temperature. The sample should be taken from the leeward side of the ship, and well forward of all outlets. The thermometer should be read as soon as possible after it has attained the temperature of the water sample. When not in use the bucket should be hung in a shady place to drain.


93

A sea-bucket should be designed to ensure that sea water can circulate through it during collection and that the heat exchange due to radiation and evaporation is minimum. The associated thermometer should have a quick response and be easy to read and should preferably be fixed permanently in the bucket. If the thermometer must be withdrawn for reading, it should have a small heat capacity and be provided with a cistern around the bulb of volume sufficient that the temperature of the water


94

withdrawn with it does not vary appreciably during the reading. The design of bucket should be deemed adequate for the purpose by the Member recruiting the ship for observations.

Sea-buckets of good design (not simple buckets of canvas or other construction) can be expected to agree well over an extensive rang of conditions. However, they are less convenient to use than instruments attached to the ship and their use is sometimes restricted by weather conditions.


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7.4.2.3 INTAKE AND TANK THERMOMETERS

The thermometer provided within the intake pipe when the ship is built is normally not suitable for the measurement of sea surface temperature. Thus the Member recruiting the ship should, with the permission of the shipping company concerned, install a thermometer appropriate for the purpose. This should preferably be mounted in a special tube providing adequate heat conductivity between the thermometer bulb and the intake water.

When a direct-reading thermometer is installed in cramped conditions the observer should be warned of the possibility of error in his readings due to parallax. A distant-reading system with the display elsewhere (e.g. in the engine room or on the bridge) overcomes this problem. The observer should also be aware that for ships of deep draught, or when a marked temperature gradient exists within the sea surface layer, intake temperature readings usually differ considerably from those close to the sea surface. Finally, of course, the intake temperature should not be taken when the ship is stationary, for then the cooling water is not circulating.

7.4.2.4 HULL ATTACHED THERMOMETERS

Hull-attached thermometers provide a very convenient and accurate means of measuring sea- surface temperature. They are necessarily distant-reading devices, the sensor being mounted either externally in direct contact with the sea using a "through-the-hull” connection, or internally (the “limpet” type) attached to the inside of the hull. Both types show very good mutual agreement, with the ”through-the-hull” type showing a slightly quicker response.


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7.5 VISIBILITY

On a large ship it is possible to make use of objects aboard the ship for estimation when the visibility is very low, but it should be recognized that these estimates are likely to be in error since the ship may affect the air. For the higher ranges, the appearance of the land when coasting is a useful guide, and the distance of landmarks, just as they are appearing or disappearing, may be measured from the chart. Similarly, in the open sea, when other ships are sighted and their distances known, e.g. by radar, the visibility can be obtained. In the absence of other objects, the appearance of the horizon, as observed from different levels, may be used as a basis of the estimation. Although abnormal refraction may introduce errors into such methods of estimation, they are the only ones available in some circumstances. At night, the appearance of navigation lights can give a useful indication of the visibility.

7.5 CLOUD COVER (CLOUD AMOUNT)

The total amount of cloud should be estimated by considering how much of the apparent area of the sky is covered by cloud. In determining the amount of cloud of a


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specified form or type present, the observer should estimate, by taking into consideration the evolution of the sky, the cloud amounts of each layer or mass at the different levels as if no other clouds were present.

Care should be taken to avoid unconsidered guessing and the best safeguard against this is knowledge of the evolution of the clouds under consideration. On occasions of fog which is so thick as to make it impossible to tell whether there is cloud above or not, the state of sky should be recorded as sky obscured. If the cloud can be seen through the fog, the cloud amount should be estimated as well as circumstances permit. If the sun, moon or stars can be seen through the fog and there is no evidence of cloud above the fog, the state of the sky should be recorded as clear.

At night the observation of total cloud amount is noted by observing which stars are showing and which are obscured. It is more difficult to differentiate between low, middle and high clouds and a reliable observation depends upon the degree of illumination and the experience of the observer.

7.5.1 CLOUD HEIGHT ESTIMATION (NH)

In the absence of instrumental aids the cloud-base height must be estimated. In order to improve their ability to do this, observers should be encouraged to take every opportunity of checking their estimates against known heights, e.g. when a cloud base is seen to intercept a mountainous coast. (Although in such circumstances the cloud base may be lower at the mountain than at sea). At stations where the observer has reports available from aircraft descending or ascending in the vicinity he can relate these to what he sees and so provide reports sufficiently reliable for meteorological purposes. At other stations estimates can sometimes be widely in error. The heights of the bases of the various types may be expected to be between the following limits, roughly.

7.5.1.1 LOW CLOUDS (CL)

Stratus: usually below 600 m (2000 ft) and sometimes nearly down to the surface.

Cumulonimbus: 600 - 1500 m (2000 - 5000 ft).

Stratocumulus: 450 - 1350 m (1500 - 4500 ft).


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Cumulus: 450 - 1500 m (1500 - 5000 ft).

7.5.1.2 MIDDLE CLOUDS (CM)

Nimbostratus: 150 - 2000 m (500 - 6500 ft), usually below 600 m (2000 ft) in moderate rain or snow.

Altostratus and Altocumulus: 2000 - 5500 m (6500 - 18000 ft).

7.5.1.3 HIGH CLOUDS (CH)

Usually above 5500 m (18000 ft).

7.6 WEATHER (WW AND W1W2)

“Past weather " shall be selected in such way that " Past weather " and " Present weather " together give as complete a description as possible of the weather in the time interval concerned. For example, if the type of weather undergoes a complete change during the time interval concerned, “Past weather " shall describe the weather prevailing before the type of weather indicated by " Present weather " began.

7.7 WAVES

7.7.1 DEFINITION OF WIND WAVE:

System of waves observed at a point that lies within the wind field producing the waves.


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7.7.1.1 DEFINITION OF SWELL WAVE

System of waves observed at a point remote from the wind field, which produced the waves, or observed when the wind field, which generated the waves no longer, exists.

7.7.1.2 WAVE DIRECTION

The direction from which the waves are coming is most easily found by sighting along the wave crests and then turning 90° to face the advancing waves. The observer is than facing the direction from which the waves are coming.

7.7.1.3 WAVE PERIOD

The period of the waves is the time between the passage of two successive wave crests past a fixed point. The average value of the wave period is reported, as obtained from the larger well-formed waves of the wave system being observed. This is the only element, which can actually be measured on board moving merchant Ships. If a stopwatch is available, only one observer is necessary; otherwise two observers and a watch with a second hand are required. The observer notes some small objects floating on the water at some distance from the ship: if nothing better is available, a distinctive patch of foam can usually be found which remains identifiable for the few minutes required for the observations.

He starts his watch when the object appears at the crest of the wave. As the crest passes on, the object disappears into the trough, and then reappears on the next crest, etc. The time at which the object appears to be at the top each crest is noted. The observations are continued for as long as possible; they will usually terminate when the object becomes too distant to identify, on account of the ship's motion. Obviously the longest period of observation will be obtained by choosing an object initially on the bow as far off as it can be clearly seen.

Another method is to observe two or more distinct consecutive periods from an individual group while the watch is running continuously: with the passage of the last distinct crest of a group or the anticipated disappearance of the object, the watch is


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stopped, then restarted with the passage of the first distinct crest of a new group. The observer keeps count of the total number of periods until he reaches 15 or 20 at least. With observations of a period less than five seconds and low wind velocity, the above observation may not be easily made, but such waves are less interesting than those with longer periods.

7.7.1.4 WAVE HEIGHT

The average value of the wave height (vertical distance between trough and crest) is reported, as obtained from the larger well-formed waves of the wave system observed. The following table shows roughly which height of WIND WAVES (SEA) may be expected in the OPEN sea, remote from land. In enclosed waters, or when near land with an offshore wind, wave heights will be smaller and the waves steeper. Furthermore the lag effect between the wind getting up and the sea increasing should be borne in mind.

wind force [Beaufort] probable height [meters] probable max. height

[meters]

0 0 0

1 0.1 0.1

2 0.2 0.3

3 0.6 1

4 1 105

5 2.0 2.5

6 3 4

7 4 5.5

8 5.5 7.5

9 7 10

10 9 12.5

11 11.5 16

12 14 -


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7.7.1.5 TSUNAMI WAVES

Tsunamis or seismic tidal waves are produced because as a result of an earthquake a

sudden change occurs in the bottom relief in the area of the earthquake. This may be a sudden

subsidence of a fault block in the earth's crust of the seabed, a sudden lifting of such a fault

block, or even a sudden subsidence of the bed along a continental shelf. This is accompanied by

enormous water movements in the area of sea above it. As a result of this extremely long sea

waves are produced that can cross a whole ocean virtually un-subdued.

In the open sea these waves are not observed because of their length and relatively low

height. The wave length in the open sea is around 500 - 1000 km, the period is in the order of ½

- 1 hour, and the speed at which the wave moves is for deep oceans 500 - 1000 km/hour. The

amplitude of the wave in the open sea is usually not more than ½ m. When approaching coasts

these waves may however reach a height of a few meters to 10, 20 m or more. This height

depends on the configuration of the seabed off the coast and the shape of the coast itself.

Narrow elongated bays are notorious in this respect. Observations of Tsunamis are then only

limited to the immediate vicinity of the coast. Because of the dependence of the phenomenon on

the local conditions, the observations may differ considerably for points located near one

another.

7.8 Cloud Information

7.8.1 DESCRIPTION ALTOCUMULUS

White or grey, or both white and grey, patch, sheet or layer of cloud, generally with shading, composed of laminae, rounded masses, rolls, etc., which are sometimes partly fibrous or diffuse and which may or may not he merged; most of the regularly arranged small elements usually have an apparent width between one and five degrees. Main differences between Altocumulus and similar clouds of other general


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Cirrus. Altocumulus clouds sometimes produce descending trails of fibrous appearance (virga). When this is the case, the clouds are regarded as Altocumulus and not as Cirrus, so long as they have a part without a fibrous appearance or a silky sheen.

Cirrocumulus. Altocumulus may sometimes be confused with Cirrocumulus. In case of doubt, if the clouds have shading, they are by definition Altocumulus, even if their elements have an apparent width of less than one degree. Clouds without shading are by definition Altocumulus if most of the regularly arranged elements, when observed at an angle of more than 30 degrees above the horizon, have an apparent width between one and five degrees. A corona or irisation is often observed on thin parts of Altocumulus but only infrequently on Cirrocumulus.

Altostratus. An Altocumulus layer may sometimes be confused with Altostratus; in case of doubt, clouds are called Altocumulus if there is any evidence of the presence of laminae, rounded masses, rolls, etc.

Stratocumulus. Altocumulus, with dark portions, may sometimes be confused with

Stratocumulus. If most of the regularly arranged elements have, when observed at an angle of more than 30 degrees above the horizon, an apparent width between one and five degrees, the cloud is Altocumulus.

Cumulus. Altocumulus in scattered tufts may be confused with small Cumulus clouds; the Altocumulus tufts, however, often show fibrous trails (virga) and moreover are, in their majority, smaller than the Cumulus clouds.

7.8.2 DESCRIPTION ALTOSTRATUS

Altostratus. Grayish or bluish cloud sheet or layer of striated, fibrous or uniform

appearance, totally or partly covering the sky, and having parts thin enough to reveal the sun at least vaguely, as through ground glass. Altostratus does not show halo phenomena.


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Main differences between Altostratus and similar clouds of other genera

(a) Cirrus. Sheets or layers of Altostratus may, on rare occasions, degenerate into patches,

which may be confused with patches of dense Cirrus. Altostratus patches however have a greater horizontal extent and are predominantly grey.

(b) Cirrostratus. A high and thin layer of Altostratus may he mistaken for a veil of Cirrostratus. It is sometimes possible to identify the doubtful cloud by remembering that Altostratus prevents objects on the ground from casting shadows and that it may show a ground glass effect. If halo phenomena are present, the doubtful cloud is Cirrostratus.

(c) Altocumulus and Stratocumulus Altostratus sometimes has gaps, breaches or rifts; care should be exercised not to confuse it with an Altocumulus or Stratocumulus sheet or layer showing the same features. Altostratus is distinguishable from Altocumulus and Stratocumulus by its more uniform appearance.

(d) Nimbostratus. A low, thick layer of Altostratus may he distinguished from a similar layer of Nimbostratus by the presence in Altostratus of thinner parts through which the sun is, or could be, vaguely revealed. Altostratus is also of a lighter grey and its under surface is usually less uniform than that of Nimbostratus. When, on moonless nights, doubt exists regarding the choice of the designation Altostratus or Nimbostratus, the layer is by convention called Altostratus, if no rain or snow is falling.

(e) Stratus Altostratus is distinguishable from Stratus, with which it may be confused, by its ground glass effect. Furthermore, Altostratus is never white, as thin Stratus may be when observed more or less towards the sun.

Description Nimbostratus

Grey cloud layer, often dark, the appearance of which is rendered diffuse by more or less continuously falling rain or snow, which in most cases reaches the ground. It is thick enough throughout to blot out the sun. Low, ragged clouds frequently occur below


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the layer, with which they may or may not merge. Main differences between Nimbostratus and similar clouds of other genera.

(a)Altostratus

Thin Nimbostratus may be confused with thick Altostratus. Nimbostratus generally has a darker grey color than Altostratus. By definition, Nimbostratus is sufficiently opaque throughout to hide the sun or moon, whereas Altostratus hides the luminary only when the latter is behind the thickest parts. If on dark nights, doubt exists regarding the choice of the designation Nimbostratus or Altostratus; the cloud is by convention called Nimbostratus when rain or snow reaches the ground.

(b) Altocumulus and Stratocumulus

The lack of clearly defined elements or its lack of a distinct lower surface distinguishes nimbostratus from a thick layer of Altocumulus or Stratocumulus.

(c) Stratus

Nimbostratus is distinguished from thick Stratus by the fact that it is a dense cloud producing rain, snow or ice pellets; the precipitation which may fall from Stratus is in the form of drizzle, ice prisms or snow grains.

(d) Cumulonimbus

When the observer is beneath a cloud having the appearance of a Nimbostratus, but accompanied by lightning, thunder or hail, the cloud should by convention is called Cumulonimbus.

7.9 ICING

Ice accretion is extremely hazardous in its effects on small ships, particularly on vessels of less than about 1000 gross tonnage. Even on ships of the order of 10,000 gross tonnage it can cause radio and radar failures due to the icing of aerials. Visibility


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from the bridge may also be affected. Problems have occurred due to icing on the deck cargoes of large container ships. Apart from its possible effect on stability it may cause difficulty in unloading cargo at the port of destination when containers and their lashings are frozen solidly to the deck. Fishing vessels are particularly vulnerable to ice accretion.

7.9.1 METEOROLOGICAL FACTORS RELATED TO ICING

The most important meteorological elements governing ice accretion at sea are the wind speed and the air temperature. The higher the wind speeds relative to the ship and the lower the air temperature, the greater the rate of ice accretion. There appears to be no limiting air temperature below, which the icing risk decreases.

7.9.2 TYPES OF ICING AT SEA

There are two main types of icing at sea: icing from seawater and icing from fresh-

water. Icing from seawater may be due either to spray and seawater thrown up by the

interaction between the ship, or installation, and the waves or else to spray blown from

the crests of the waves or both. Icing from fresh-water may be due to freezing rain

and/or drizzle, or occasionally wet snow followed by a drop in temperature, or it may

be due to freezing fog. Both types may occur simultaneously

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8. WAVE FORECASTING

Since in most cases the computations cannot be checked due to lack of actual observations,

the wave forecaster must have a notion of possible values of wave height and period which can occur

in the sea or ocean area he is interested in and also his experience should have given him a feeling for

the probable values which might occur under the given wind conditions. It is of great importance,

therefore that he starts his training with a detailed study of the geography and climatology of the area

of interest, so that he knows the limitations of wind fetch for certain wind directions, the existence of

strong ocean currents, the typical configuration of wind fields in the weather patterns prevailing over

the area and the climatological probability of wind speeds and directions. If statistical information

about ocean waves is available, he should study this information and try to understand why certain

conditions do not occur in one area, although they may be common in another.

It is useful to know the range of wave heights and periods which may occur at sea in general.

Characteristic wave heights will rarely exceed 10m; characteristic wave period usually vary between 4

and 15 seconds and are seldom greater than 20 secs.

Fig. 1 shows the hind cast significant wave heights over Bay of Bengal using the Sverdrup

Munk Bretschneider (SMB) prediction technique during peak monsoon months June, July and

August. (Rao and Prasad 1984).

Due to the importance of the global shipping in recent years, numerous empirical and

numerical wave models have been developed in various parts of the globe. Some of the empirical

models available for the north Indian oceans are available in literature viz.; Thiruvengadathan (1984),

Ray (1988), Mukherjee and Sivaramakrishnan (1977, 1981, and 1983).

The important wave prediction methods in use are:

Significant wave method

Spectrum method

Numerical methods viz.;


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Decoupled propagation (DP) model: Models of this class generally represent the wave

spectrum as a two dimensional discredited array of frequency-direction cells in which each cell or

component propagates at its appropriate group velocity along its own path. The components are

grown according to a source function of the form

S= A + B * E (f, θ)

As non-linear energy transfer is basically neglected, the factors A and B are usually

empirically determined.

Coupled Hybrid (CH) model: The combination of a parametric wind-sea model and a

decoupled propagation swell model is termed a coupled hybrid (CH) model.

Coupled discrete (CD) model: The basic technique for non-linear transfer in this is

similar to the one used in CH model; while the main difference is in the number of degrees of

freedom. Also CD models parameterise the high-frequency part of the spectrum.

Third generation model: These models initially developed by an international group

(Wave Modelling group WAM, KNMI, DeBilt, Netherlands) applies a new approach to the

parameterisation of the non-linear source term. The global model thus developed are transformed into

regional models as well.

The observational data base for all the above methods are:

(a) Visual observation on, wave height in metres, wave period in seconds and wave

direction in tens of degrees

(b) Instrumental observations viz.

Pressure type wave recorder in coastal stations.

Ultrasonic Type Wave Recorder on sea bed or above sea surface (Platform)

Buoy type wave recorder

Ship borne type wave recorder

(c) Remote sensing using, Radar Altimeter, Synthetic Aperture Radar (SAR) and Scatter

meter

Wave forecasting by manual methods are discussed here in brief and reference is provided for

other such methods which make use of nomograms, as in figures 2 & 3, for wave forecasting.

In Figures 2 and 3, the dimensional deep-water curves are reproduced. These can be used

directly in wave calculations. In the former, the thick dark lines represent the growth of waves along


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increasing fetch (the thin lines indicate the fetch). Each line has constant wind speed. The

characteristic wave height (Hc) can be read off from the horizontal lines, the characteristic period (Tc)

from the dotted lines, and the vertical lines indicate the duration at which that stage of development

will be reached. If the duration is limited, the waves will not develop along the thick dark line beyond

that point, irrespective of the length of the fetch. It is important to note the curvature in these lines.

They are nearly horizontal near the right hand side of the diagram. This means that, for a given wind

speed, the waves stop growing when the duration or fetch is large enough.

Example 1: U = 15 m s –1

; fetch = 200 km; duration = 6 h. At this wind speed and fetch (from Figure

2), more than six hours are required for the waves to become fully developed. The duration is

therefore the limiting factor and from the t = 6 line intersecting with the U = 15 line, we can read off

that Hc = 2.9 and Tc = 5.8 s.

Example 2: U = 15 m s –1; fetch = 200 km; duration = 18 h. For the same conditions as Example

1, except that waves develop for a further 12 hours, we see that the fetch is now the limiting

factor in their growth. The intersection of the F = 200 line with the U = 15 line determines that

Hc = 4.0 m and Tc = 7.3 s.

Much experience is needed, however, to analyse an entire chart within a reasonable time limit

mainly because one has to work with constantly changing wind conditions. Some empirical working

procedures, which have proved their value in actual practice, are briefly mentioned here.

8.1 FRESHENING OF THE WIND AT CONSTANT DIRECTION :

This is a frequent occurrence. For quick calculations; subtract one-quarter of the wind

increase from the new wind speed and work with the value thus obtained. Example: the wind

speed has increased from 10 knots to 20 knots over the last 12 hours; to compute the

characteristic wave height, use a wind speed of 17.5 knots over a duration of 12 hours. When

sharp increases of wind speed occur, it is advisable to perform the calculation in two steps.

8.2 CHANGING WIND DIRECTION:


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If the direction changes 30 o or less, wave heights and periods are computed as if no

change had occurred; the wave direction is assumed to be aligned with the new wind direction.

At greater changes, the existing waves are treated as swell and the newly generated waves are

computed with the new wind direction.

8.3 SLACKENING OF THE WIND:

When the wind speed drops below the value needed to maintain the heights of existing waves,

the waves turn into swell and should be treated as such. As a first approximation, swell may be

reduced in height by 25 percent per 12 hours in the direction of propagation. For instance, swell

waves 4 m high and with a period of 10 s will cover a distance of 182 n.m. in 12 h and at the new

position, their height will have decreased to 3 m.

All the above examples have been related to deep-water conditions.

Computation of swell:

For most practical applications two different types of situations need to be

distinguished:

(a) Swell arriving at the point of observation from a storm at a great distance, i.e. 600

n.m. or more.

In this case, the dimensions of the wave-generating area of the storm (e.g. tropical

cyclone) can be neglected for most purposes of swell forecasts. The important effect

to be considered is wave dispersion;

(b) Swell arriving at the point of observation from a nearby storm:

Because of the proximity of the storm edge, swell, fanning out from different points

of the storm edge, may reach the point of observation. Apart from wave dispersion,

the effect of angular spreading should also be considered.

In swell computations, we are interested in the propagation of wave energy; therefore,

the group velocity of the individual sinusoidal wave components should be considered. Since

large distances are often involved, it is more convenient to measure distances in units of

nautical miles and group velocities in knots. The wave period T is measured in seconds as usual.


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Distant storms:

In the case of a distant storm the questions to be answered in swell forecasting are:

(a) When will the first swell arrive at the point of observation from a given direction?

(b) What is the range of wave periods at any given time?

(c) Which wavelengths are involved? and possibly;

(d) What would be the height of the swell?

The known data to start with are the distance Rp (n.m.) from storm edge to point of

observation P, the duration Dp of wave generation in the direction of P and the maximum

wave period generated in the storm area.

The period for the fastest and slowest waves are calculated and from this, the range of

possible wave frequency are arrived at. The range of frequencies becomes smaller at greater distances

from the storm.

An increasing number of forecasting centres have been introducing numerical models. An

effective use of the products of such models is only possible if the forecasters have sufficient

knowledge about the physical backgrounds of wave modelling.

Third generation models are becoming operational with the availability of satellite data

relevant to windfield analysis on a larger scale. Such data facilitate the provision of wind fields with

improved accuracy leading to essential improvements in wave forecasting. Some of the websites

which provide these forecasts for the Indian Ocean Region are;

http://www.oceanweather.com/data

http://polar.wwb.noaa.gov/cgi-bin/nww3.cgi

http://facs.scripps.edu/surf/inda.html

http://www.incois.gov.in/Incois/advisory_osf_main.jsp


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9. GUIDELINES TO MARINE FORECASTING AND VERIFICATION

9.1 INTRODUCTION

Not many people are as much affected by weather as the mariners. An unexpected

change in winds, state of sea, or visibility can reduce the efficiency of marine operations and

threaten the safety of a vessel and its crew. All marine operations benefit from weather

forecasts. Knowledge of the wind and wave conditions enhances the safety and efficiency of

offshore operations and drastically truncates enormous unforeseen expenditure.

The meteorological forecast products should be clear and concise and should be easily

comprehended by users. The products should be issued in a specific format containing all the

required information.

If the regions are demarcated for any specific convenience, there should be consistency

along the demarcated regions. So also, the forecast products need to be consistent with the

actual weather conditions.

It is essential for the forecaster to have the knowledge of the climatology of the regions

for which forecast is being issued. The forecaster needs to give a brief description of the

prevailing synoptic conditions as prelude to the forecast. The forecast needs to be a built-up

situation of the current analysis comprising substantial ship and buoy data, a judicious

compromise of analysis of satellite and various numerical products.

It is advisable to develop a daily, updated ‘nowcast’ – a comparison between the

predictions of computer models of date and what is currently happening. This method helps the

forecasters to fine-tune their assessment. Coastal water forecasts are for areas within 60

nautical miles of the coast.

High seas forecasts are issued twice daily and warnings to shipping on the high seas are

issued whenever gale, storm force or hurricane force winds are expected. The initial warning

attempts to provide around 24 hours lead-time and warnings are renewed every 6 hours.


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9.2. GENERAL GUIDELINES.

The forecaster is responsible for the timeliness, currency, and accuracy of the marine

weather products issued for the marine area of responsibility. The forecaster should endeavour

to maintain spatial and temporal consistency between adjoining offices and from one forecast

period to the next. Forecasters from Forecasting offices have to consult the offices of adjoining

areas to minimize discontinuities in products prepared at adjoining offices.

Marine forecasts include significant or predominant weather events impacting marine

users. Wind and sea conditions are always the chief products of marine forecasts. To most

effectively describe these conditions, one value or a small range of values are used.

Wind speed is the average speed of the wind over a 10-minute period at a height of 10

metres above the surface. As a guide, double the wind speed in knots to convert to kilometres

per hour, for example 15 knots is approximately 30km/h. Wind direction is given in 8 compass

points for forecasts and 16 for observations and is the direction the wind is coming from.

Gusts are increases in wind speed lasting for just a few seconds. The speeds are

typically 30 to 40 per cent higher than the average wind speed, but stronger gusts are likely in

the vicinity of showers and thunderstorms.

A squall is an abrupt and large increase in wind speed with duration of the order of

minutes and which diminishes rather suddenly.

Strong wind warning : 26 to 33 knots. Gale warning 34 to 47 knots. Storm force wind

warning: 48 to 63 knots. Hurricane force wind warning : 64 knots or more.

Sea ( or wind ) waves are generated by the local prevailing wind and vary in size

according to the length of time a particular wind has been blowing, the fetch (distance the wind

has blown over the sea) and water depth.

Swell waves are the regular longer period waves generated by the distant weather

systems. There may be several sets of swell waves travelling in different directions, causing a

confused sea state.


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Sea state describes the combination of sea (wind) waves and swells. Wave height

(trough to crest) for both sea and swell refers to ‘significant wave height’ which represents the

average height of the highest one-third of the waves.

Transition terms for winds and seas should be discrete and consistently used to avoid

confusion. Wind speed transition terms such as “INCREASING” and “DIMINISHING” and

direction transition terms such as “BECOMING” and “SHIFTING” are to be used to add clarity to

the forecast trends. The terms "VEERING, BACKING, BECOMING, SHIFTING," or "RISING" may be

used when appropriate, but not "DECREASING." For seas, transition terms such as "BUILDING"

and "SUBSIDING" should be used. Tidal information may be included in the forecast in the areas

of requirement. If it is included, it should cover not cover more than 24 hours.

Marine forecasts should not use the word “under” when describing winds below a

certain

threshold. Instead the words “less than” may be used. For instance, in the High Seas Forecast,

state

“WINDS LESS THAN 20 KT” versus “WINDS UNDER 20 KT”. Similarly, when describing seas

less than a certain threshold, the words “less than” are to be used instead of “below”, such as Sea

state forecast “SEAS LESS THAN 2 MT”, as against “SEASBELOW 2 MT”. Also, the sea conditions

of Offshore Waters and High Seas are to be separately described. If sea conditions of Offshore

waters is also included, separate sentences may be used when describing the wind and sea

conditions.

9.3 UPDATE GUIDELINES.

Whenever there is any significant change in existing or expected weather conditions.

(i.e., there is a change in a warning or advisory status), forecasters should update forecasts from

the forecast which are expected to continue for more than 2 hours. If an amendment is needed

near the next scheduled forecast time (i.e., within an hour), the forecaster may issue that

forecast early in lieu of an amendment. Based on available information, use the following

guidelines for updating marine forecasts. The regions and local offices may develop local

updating procedures and criteria to supplement these.

9.3.1 WIND FORECAST NEEDS AMENDMENT IF:


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i). Unpredicted change in status of advisories or warnings.

ii). Highest sustained wind speed increased or diminished 10 KT or more from forecast (20 KT

or more if no change in hurricane force wind warning status occurs).

iii). Mean wind direction changes by more than 45 degrees from forecast when speeds equal or

exceed 20 KT.

iv). Sustained wind and/or gust conditions commence to affect marine operations adversely or

favorably.

9.3.2 SEA CONDITION

Sea condition needs amendment if unpredicted wind wave, swell, or combined seas

begin to affect marine operations either adversely or favourably.

9.3.3 VISIBILITY:

Forecast needs amendment if the forecast visibility of 5NM or more changes to 1 NM or

less over a significant part of the forecast area.

b. Forecast visibility of 1 NM or less increases to 5 NM or more over a significant part of the

forecast area.

9.3.4 WEATHER.

Amendment is to be made if significant, unpredicted changes in weather begin to affect

marine operations either adversely or favourably.

9.4 GUIDELINES FOR WARNING/ADVISORY.

If, in a forecast, a forecaster includes a range of winds or seas which cross a warning or

advisory threshold, the highest value will determine the advisory or warning category (e.g., a

gale warning is issued for a forecast of ‘Winds 25 to 35 KT’).


117

The forecaster may use gust speeds rather than the sustained winds if these values

better describe existing conditions. In such cases, a significant portion of the area/zone(s)

should be affected. As a guideline, this could include at least half of the affected area/zone(s)

through at least half the affected forecast period(s).

If the marine area is likely to have the impact of a tropical cyclone the headlines

associated with that system, as issued by the nodal agency or national weather services

supersede all other headlines.

9.5 INTERDEPARTMENTAL COORDINATION.

All the field offices and Regional offices need to interact with the field offices with

adjoining or overlapping areas of responsibility should coordinate and collaborate to ensure

products are consistent and compatible under the supervision of nodal office. It is also advisable

to have a frequent interaction with the users and allied scientific communities.

9.6. VERIFICATION

Verification of forecast is essential in two respects. One is to ensure the technical and

scientific accuracy and the other is to assess the extent of users’ requirement. Regular

verification of forecast helps to improve the capability of the forecaster. It helps to identify

consistent lapses or biases that take place in forecasts which go unnoticed by the forecaster. It is

advisable to design a system for collection of data and its verification. The forecast system must

be fair and objective.

Over space and time the verification must be element specific. Forecast accuracy is

determined by comparing the bulletins issued with actual observations. Forecast skill is a

comparison of the forecast issued with a reference forecast, like, persistence, climatology, or any

specific guidance.

Observations are instantaneous measurements of current weather conditions and may

not represent the prevailing conditions during the forecast period; thereby a satisfactory

verifying solution cannot be arrived reasonably. Forecasts and observation data are to be

collected on a regular definite time schedules.

All data should be checked for errors prior to calculation of verification of statistics. A

simple quality control method is for the forecaster to check and manually correct the data.


118

The weather elements are to be chosen which are most important for the variety of

users.

Consistent elements are to be chosen that can be tracked over time. Raw data need always to be

preserved, since the methodology might change. Using a single scoring method for all

performance is not advisable.

A simple approach to forecast verification is to identify the rainy days for a month and

compare with the forecast days with rain and obtain the percentage.

The verification scheme at times becomes difficult for want of availability of both the

forecast and observations which verify the particular element. This is a very common situation

in data sparse regions. In this case subjective verification, though not desirable, is better than

none, especially if done consistently. When both forecasts and observations are available, they

must have a space- time correspondence; each forecast must be verified against an observation

made at a point, not against “area weather”.

The practice in vogue for the verification of forecasts for sea areas is as follows:

The sea bulletin is to be judged as a whole. Sub-divisions of the sea, carry marks roughly

proportional to their area.

Marks allotted to various elements in a merchant shipping bulletin are:

Wind - 40

Weather - 40

Visibility - 20

In case of fleet forecast, the weightage is

Wind - 60

Visibility – 40

Verification of various parameters can thus be defined to evaluate the skill and efficiency

of forecast. A sample scheme to evaluate, quantitatively, the efficiency of forecast of wind,

issued for GMDSS Met Area VIII(N) is appended.


119

9.7 A SAMPLE SCHEME OF VERIFICATION OF GMDSS FORECAST

Verification for direction: For the predicted westerly wind, the percentage accuracy of the

actual wind is obtained as follows

9.7.1 VERIFICATION FOR SPEED : IT IS DONE AS PER THE FOLLOWING FORMULA

Average fc speed –Avg Actual speed

Percentage Verification = ---------------------------------------------- X 100

Average Actual Speed


120

It is shown with the help of following example for the date 09-07-2010.

The forecast area of GMDSS comprises four sectors, A1, A2, A3 and A4. The accuracy of

forecast in each sector is calculated separately for wind speed and direction and average is

taken.

A1

A2

W of 65 Deg E

E of 65 Deg E

W of 70 Deg E E of 70 Deg E

F/c

Dir

SW/W

Speed

12.5 Kts

Actual

W

10 Kts

F/c

Dir

NW

Speed : 12.5 Kts

Actual

NW

15 Kts

F/c

Dir : SW/W

Speed

17.5 Kts

Actual

SW /W

21.3 Kts

F/c

Dir

NW

Speed 17.5 Kts

Actual

SW

15 Kts

A3

A4

W of 90 Deg E

E of 90 Deg E

F/c

Actual


121

F/c Dir

SSW Speed

12.5 Kts

Actual

SW/SSW

15 Kts

F/c

Dir :

SW

Speed

12.5 Kts

Actual

NW

10 Kts

Dir : SW

Speed : 17.5 Kts

SW

10 Kts

Back To Contents

122

10. OBSERVATIONAL PROGRAMMES:

10.1 PROGRAMS OF WMO

To achieve safety at sea requires being prepared for severe storms and high waves. For

this purpose close cooperation between the meteorological, oceanographic and marine user

communities is needed to provide the necessary advisories and warnings. Also proper ship

routing strategies based on meteorological and oceanographic predictions can sav4e time and

money on long voyages. In order to address these and other oceanographic and atmospheric

issues WMO maintains a close cooperation between the Intergovernmental Oceanographic

Commission (IOC) of UNESCO. As a result of this cooperation Joint Technical Commission for

Oceanography and Marine Meteorology (JCOMM) was established to address operational issues,

such as coordinating observing systems at sea using various kinds of buoys, ships and satellites.

Many recent technological developments for measurements at sea are being deployed to

improve understanding of air-sea interaction and provide services for marine users.

VOS – The Voluntary Observing Ship Scheme is an international scheme, first

developed almost 150 years ago. The ships plying in the various oceans and seas of the world

are recruited for taking and transmitting meteorological observations. VOS ships make a highly

important contribution to the GLOBAL OBSERVING SYSTEM (JGOS) of the World Weather

Watch (WWW) and for climate studies. VOSClim is a subject of VOS and is an ongoing project

within JCOMM’s Voluntary Observing Ship’s Scheme.

Some 3000 Argo floats gather both temperature profiles down to 2000m and

measurements of subsurface currents, and then rise up to the surface to transmit the collected

data by satellite relay. These data complement the weather and water temperature observations

collected by more than 6000 voluntary observing ships, 1000 drifting buoys and 600 fixed

platforms. The latter three types of systems make both meteorological and oceanographic

measurements. These observational systems, along with remote-sensing by satellites, provide

full coverage of the oceans for operational forecasts and warnings, and for research as part of

the Global Climate Observing System (GCOS) and the Global Ocean Observing System (GOOS).

Ship of Opportunity Programme (SOOP) of JCOMM also makes use of volunteer

merchant ships, which routinely travel strategic shipping routes. Ships’ Officers are trained to

deploy Expandable Bathythermographs (XBTs) at pre-determined sampling intervals to acquire


123

temperature profiles in the open ocean. The SOOP data are vital in particular to the seasonal to

inter-annual climate prediction.

Global Sea Level Observing System (GLOSS) is an international programme

conducted under the auspices of JCOMM of the WMO and IOC. GLOSS aims at the establishment

of high quality global and regional sea level networks for application to climate, oceanographic

and coastal sea level research.

Among the important frameworks for operational use of better forecasts and

warnings over the high seas is the International convention for the Safety of Life at Sea (SOLAS)

which now incorporates the Global Maritime Disaster and Safety System (GMDSS) of the

International Maritime Organization.

Marine pollution incidents also threaten coastlines and near –shore biological

resources, algae, shellfish, fish, seabirds and vegetation. Techniques have been evolving for

corralling or dispersing oil slicks, as their movements depend on the winds and ocean currents

at the time of the incident, as well as immediately after. Meteorologists and oceanographers are

therefore key players in the Marine Pollution and Emergency Response Support System

(MPERSS) for international waters. These professionals are among the first to be consulted on

spills within national coastal waters and inland waterways.

10.2 REGIONAL PROGRAMS

Some of the major experiments connected with monsoon studies over the Indian

Ocean region are (i) IIOE(1963-66) (ii) MONEX (1979) (iii) TOGA-INDIA(1986-95) (iv) INDOEX

(1999) and (v) BOBMEX(1999) & ARMEX(2002-03).

10.2.1 INTERNATIONAL INDIAN OCEAN EXPEDITION(IIOE)

During IIOE observations were collected not only from routine surface and upper

observatories but also from merchant ships, special research ships, commercial aircrafts, special

research aircrafts, buoys in the ocean and satellites. Observations were carried out on board


124

ships from India and USA. Observations were also made from island stations located in the

Indian Ocean and surrounding areas.

(i) Following IIOE, there were several field programmes to understand the

complexities of the monsoon system, prior to MONEX 1979. The programmes

prior to MONEX included the INDO-SOVIET Monsoon Experiment -1973(ISMEX-

73) and Monsoon-77, MONEX was undertaken as a part of the First GARP Global

Experiment specially to focus the summer monsoon circulation. The observing

system consisted of civilian and research vessels from USA, USSR, France and India

apart from the upper air and coastal observations.

(ii) Tropical Ocean and Global Atmosphere Programme(TOGA)

TOGA was a part of the World Climate Research Programme. The main theme of

TOGA included measurements, monitoring and modeling of the large scale

oscillations. Study of monsoon variability was one of its important objectives.

TOGA- XBT measurements from voluntary observing ships (VOS)and ships of

opportunities(SOO) was an important observational component of the

programme.

(iii) Indian Ocean Experiment (INDOEX).

INDOEX was another extensive International programme in which scientists from

USA, Europe, India and Island countries of Maldives, Mauritius and Reunion

participated. The core theme of the experiment was to study “Natural and climate

forcing by aerosols and their feedback on regional and global climate”.

(iv) Bay of Bengal and Monsoon Experiment (BOBMEX) & Arabian Sea Monsoon

Experiment (ARMEX).

The Indian Climate Research Programme(ICRP) was launched in 1996. The ICRP

implementation plan in 1998, included a field experiment BOBMEX. This was


125

followed by a similar experiment in the Arabian Sea viz., Arabian Sea Monsoon

Experiment (ARMEX) in 2002-03 to understand the various aspects of Ocean-

Atmosphere Coupling over the monsoon region.

In view of the importance of marine services in operational and research activities of

IMD and importance of PMOs in liaisoning national meteorological service and the shipping

community , IMD is committed to modernize marine services by introducing automation in data

recovery, transmission and archival with inbuilt general quality check. Advent of Automatic

Weather System (AWS) has made it possible for VOS & ORV to record meteorological

observations continuously and can provide data at multiple sampling rates. This high resolution

data can be transmitted through INMARSAT and other transmission modes. Data from VOS/ORV

equipped with AWS can provide real time data for assimilation into Numerical Weather

Prediction (NWP) models. In the delayed mode, these high sampling rate data from AWS can be

utilized for validation of model outputs and satellite observations.

10.2.3 VOSCLIM PROJECT

For well over 100 years, the weather observations from merchant ships have been used to

define our knowledge of the marine climate. This function continues within the Voluntary Observing

Ships (VOS) program as the Marine Climatological Summaries Scheme. However the main emphasis

of the VOS program has traditionally been the provision of data required for atmospheric weather

forecasting. Today, the initialization of numerical weather prediction models remains an important

use of weather reports from the VOS. However recent trends, such as the increasing availability of

data from satellite sensors, and the increased concern with regard to climate analysis and prediction,

are making further requirements for data from the voluntary observing ships (VOS).

The main purpose of voluntary ships climate project is to provide a high quality set of

marine met observations.


126

There is a growing need for higher quality data from a sub-set of the VOS. Improved meta-

data (ships dimensions etc) with regard to the ship and observing practices, and improved quality

control of the observations, are the initial priorities for the VOS Climate project. Other desirable

enhancements to the VOS system include increased use of automatic coding and improved

instrumentation and detailed information of how the observations are collected.

Such observations are of great value to operational marine meteorological forecasting.

Climate studies rely on increased accuracy of good observation. The primary objective of the project

is to provide a high-quality subset of marine meteorological data, with extensive associated metadata,

to be available in both real time and delayed mode.

Eventually, it is expected that the project will transform into a long-term, operational

program. Specifically, the project gives priority to the parameters like wind direction and speed, sea

level pressure, sea surface temperature, air temperature and humidity.

Data from the project will be used to input directly into air-sea flux computations, as part of

coupled atmosphere-ocean climate models; to provide ground truth for calibrating satellite

observations; and to provide a high-quality reference data set for possible re-calibration of

observations from the entire VOS fleet. VOSCLIM is intended to produce high-quality data and

therefore the selection of ships is a very important part of this project.

10.2.4 THE WMO VOLUNTARY OBSERVING SHIPS SCHEME

"WMO Voluntary Observing Ships Scheme" is the international scheme by which ships

plying the various oceans and seas of the world are recruited for taking and transmitting

meteorological observations Aim of the scheme to establishment of a uniform system for the

collection of meteorological and oceanographic data from the oceans and the use of these data

for the benefit of shipping in return.

" The Contracting Governments undertake to encourage the collection of meteorological data

by ships at sea and to arrange for their examination, dissemination and exchange.. "Voluntary

observing ships (VOS) are the main source of marine meteorological information , and make a highly

important contribution to the Global Observing System (GOS) of the World Weather Watch

(WWW).


127

Shipping has assisted in the scientific exploration of the oceans and also in the

development of suitable measuring techniques for use of ship borne observers. The co-

operation of voluntary observing ships is sought in each of the large-scale scientific experiments

conducted by special research vessels to furnish the additional data needed for complete

analysis of environmental conditions. The participation of these ships is regularly requested in

technical studies and investigations concerning observing methods, such as the measurement of

sea-surface temperature, precipitation, wind etc.

10.2.5 VOSCLIM PROJECT

The first session of the JCOMM Subgroup on the VOS had proposed the development of a

project to establish a subset of the VOS, to provide high quality data and metadata, to serve as a

reference data set for air-sea flux computations, in particular in support of global climate

studies.

VOSCLIM is an important project for global climate studies, whose success will depend

on the combined efforts of many people and institutions. These include in particular ships'

officers and crew who are motivated, well trained and conscientious. In addition, it recognized

that, for many studies, it may be extremely beneficial to be able to associate high quality surface

meteorological observations with coincident.

10.2.6 OBJECTIVES

The primary objective of the project is to provide a high-quality subset of marine data,

with extensive associated metadata, to be available in both real time and delayed mode. The

project gives priority to the following parameters:

wind direction and speed, sea level pressure, sea surface temperature, air temperature

and humidity. Data from the project will be used : to input directly into air - sea flux

computations, as part of coupled atmosphere - ocean climate models ; to provide ground truth

for calibrating satellite observations ; and to provide a high - quality reference data set for

possible re-calibration of observations from the entire VOS fleet. Requirements, rationale and

scientific justification for the project are detailed below. .


128

10.2.7 CLIMATE RESEARCH AND CLIMATE PREDICTION

Coupled numerial models of the atmosphere and ocean are used for climate research

and climate change prediction. Because the time and space scales for circulation features in the

atmosphere and the ocean are very different, the ocean surface is an important interface for

modest verification. The simulated air-sea fluxes of heat, water and momentum must be shown

to be realistic, if there is to be confidence in the model predictions. At present the uncertainity

in our knowledge of these surface fluxes is of a similar order to be spread in the model

predictions (WGASF, 2000). Partly this is due to the limitations of the parameterisation

formulae used to calculate the fluxes. Verification of the model predictions of near surface

meteorological variables (air temperature, humidity, SST etc.) against high quality in situ

observations from moored "flux" buoys and specially selected VOS is required

Ship parameters

Code 1 ss Instantaneous ship's speed in knots at time of observation

Code 2 DD Ships heading in tens of degrees true

Code 3 LL Maximum height in meters of deck cargo above summer

maximum load line

Code 4 hh Departure of summer maximum load line from actual sea

level (m)

Wind

Code 5 ff Relative speed in knots or m/s (in conformity with wind

code indicator)

Code 6 DD Relative wind direction in tens of degrees (00 to 36) off

the bow.

This information will be included in Section 2 of the SHIP code, in optional group

to be introduced after the ICE groups. The groups will be prefixed by CLIM, and will

be the form 1ssDD 2LLhh 3ffDD, to be extended as required.

Back To Contents

129

11. CURRENT METHODOLOGY/DIFFERENT WEB SITES AND OTHER AIDS

Some of the numerical models available for the Indian Ocean region

Model Name Website Products

OCEAN WEATHER

GLOBAL ANALYSIS


Area- Tropical Indian Ocean

Wave forecast,

Surface wind dir speed

ANIMATED NOAA

WAVEWATCH III

http://polar.wwb.noaa.gov/

cgi-bin/nww3.cgi

Area- Tropical Indian Ocean

Wave forecast

Surface wind dir speed

fleet numerical

meteorology and

oceanography centre

(Model-COAMPS)

http://www.fnmoc.navy.mil/

PUBLIC

Area-Tropical Indian Ocean

SST analysis

ANIMATED WIDE

INDIAN OCEAN

WAVE HEIGHT


Area – Tropical Indian Ocean

Sea wave ht & period

fleet numerical

meteorology and

oceanography centre

(Model-NOGAPS)


PUBLIC

Area-Tropical Indian Ocean

Surface wind,

streamlines,wave,SLP,

200 hpa strmlines,

850-200 windshear,

850 and 200 hpa wind barbs

NOAA WAVEWATCH

III wave models


waves/main_table.html

Area –north Indian ocean

Peak wave dir & speed, secondary

wave dir & speed, significant wave

height, sea, swell direction, period

& height

http://www.oceanweather.com/data/global.html

http://www.oceanweather.com/data/global.html


http://polar.wwb.noaa.gov/cgi-bin/nww3.cgi?run=0&map=5&fld=2&tme=24&act=go&pnt=1

http://polar.wwb.noaa.gov/cgi-bin/nww3.cgi?run=0&map=5&fld=2&tme=24&act=go&pnt=1


http://www.fnmoc.navy.mil/PUBLIC












http://polar.wwb.noaa.gov/waves/main_table.html

http://polar.wwb.noaa.gov/waves/main_table.html



130

Indian Ocean, East Africa

Forecast weather forecast surf,

surfing conditions

http://www.wannasurf.com/forecast/

Indian_Ocean/index.php3

Surface wind dir

speed,

Wave ht and period

Incois - Experimental Ocean

State Forecast

Indian National Centre for Ocean

Information Services (INCOIS)

http://www.incois.gov.in/Incois

/advisory_osf_main.jsp

IMAGES. Wave.

Swell. Mixed Layer

Depth.

UKMO www.heto.gov.uk/sec2/sec2cyclone

GAUM http://metoc.nyP.Met.O.c.navymil.

Back To Contents

http://www.wannasurf.com/forecast/Indian_Ocean/index.php3



http://www.wannasurf.com/forecast/



http://www.incois.gov.in/Incois+/

http://www.incois.gov.in/Incois+/

http://www.heto.gov.uk/sec2/sec2cyclone

http://metoc.nypmoc.navymil./

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Apendix Section

This page is purposely kept blank for Notes

132

12. 1 APPENDIX 1 SHIP WEATHER LOG


135

136

12.2 APPENDIX 2 ADDRESS OF PORT MET OFFICES IN INDIA

Address of PMO & Name Of

PMO

Name of Port Met

Officer & designation Telephone Nos

Working

Hours E-mail address

Fax No.

Port Meteorological Office,

Director,Regional Meteorological Centre,

Near RC Church, Colaba,

Mumbai - 400 005

Shri R.R.Sayyad,

A.M.II

022 22174720

Mobile No.

c/o Shri Singh

9323738429

0930 -1800

5 days

week

[email protected] 022 22154098

Port Meteorological Liaison Office,

Director,Goa Observatory,

Alkimoh, Panjim

Goa – 403 001

Shri A.D.J.D’souza,

A.M.II

0832 2425547

Mobile No.

C/oShri A.D.J.D’souza

9860998535

0900-1730

N.A N.A.

Port Meteorological Office

Director in-charge,Regional

Meteorological Centre,

Inspectorate Section/PMO Unit,

New No.6, College Road,

Chennai - 600 006

Shri E.Kulandaivelu,

Director

044 28230091/92/94,

Ext.No.Ins.Section,

234,236,238

0915 -1745

[email protected]

[email protected]

,

044 28271581

(ACWC Chennai)






137

Port Meteorological

Office,Visakhapatnam

Director I/C

Cyclone Warning Center,

Chinna Waltair

Opposite Andhra University,

Vishakhapatnam - 530 017

Shri G.V.Rama Krishna Rao,

A.M.I

0891-2543031

2543032

2543034

2543035

2543036

1000 -

1700hrs

[email protected]

[email protected]

Fax no.

0891-2543033

0891-2543036

Regional Meteorological Centre,

Director I/C

4 Duel Avenue, Alipore,

Kolkata (West Bengal),PIN 700027

Ganesh Kumar Das

Met Gr.I

033 24793167

Mobile

No.09836213781

1000--1700

[email protected]

03324793167

Officer in charge

Port Meteorological Office,

Cochin Port Trust,

Ex-Mahavir Plantation Building,

Opp. IOC Ltd.,Indira Gandhi Road,

Willingdon Island,(South.)

Kochi - 682 003

Shri M.Sethumadhavan,

A.M.(I)

0484 2667042

Mobile No.

09446478262

Shri V.L.Rajendran,

S.A.

Mobile No.

09495779897

0900 -

1730

[email protected]





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12.3 APPENDIX 3 DIPRESSIONS / CYCLONIC STORMS DURING LAST 110 YEARS IN INDIA


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