nimet’s forcasting tools/products as aids to flood...

NigerianMeteorologicalA

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NIMET’S FORCASTING TOOLS/PRODUCTS AS AIDS TO FLOOD

MANAGEMENT

Presentedatthe1st REGIONAL STAKEHOLDERS MEETING ON MULTI-SCALE

FLOOD MONITORING AND ASSESSMENT SERVICES (MIFMAS) FOR WEST AFRICA ORGANIZED BY THE CSSTE CONSORTIUM –

ABIDJAN, COTE D’IVOIRE.Engr. Mailadi Yusuf Abba Misau,

Director Applied Meteorological Services, National Weather Forecasting and Climate Research Centre,

Nigerian Meteorological Agency – Abuja.


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Presentation outline

q Presentation looks at the theme of the stakeholders’ meeting andattempts to show how NiMet’s forecasting tools can be used bystakeholders, acting in collaboration, to predict and monitor floodsacross the Project area;

q A brief of the Nigerian Meteorological Agency with its operationsacross Nigeria is given;

q The major products of NiMet are briefly introduced and examples ofthe kind of information they contain are given;

q Rainfall and Temperature Anomalies over Nigeria are graphicallypresented to show how rainfall and temperature deviated from thenormal with overall results indicating increasing trends;

q Finally the presentation concludes by urging stakeholders to utilize theservices offered by NiMet in flood prediction and monitoring;


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Aim of the Multiscale Flood Monitoring and Assessment Services for West Africa (MIFMASS) Project

To enhance the efficiency of flood monitoring, assessment

and management in West Africa by providing earth

observation (EO) based services on real time basis to

disaster management organizations and boosting their

human capacity to adapt to these services.


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Stakeholders

• Disaster Management Organisations (DMOs)• Communities around flood prone areas

• Media• Non-governmental Organisations (NGOs) & Community

Based Organisations (CBOs)• Policy-makers

• Meteorological /Hydrological Agencies (information providers)


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Objectives of the meeting • Create regional awareness about MIFMASS and GMES &

Africa

• Enhance interaction amongst stakeholders and CSSTE-Consortium within the West Africa sub-region • Encourage an active involvement of the different

categories of stakeholders (Decision makers, DMOs, CBOs, NGOs and the Media) in the project• Engender sense of ownership, communication and

goodwill of National Governments of the participating countries


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Theme of the meeting

MULTISCALE FLOOD MONITORING AND

ASSESSMENT SERVICES FOR WEST AFRICA

PRESUPPOSES

I. FLOOD HAS OCCURREDII. SOME DAMAGE HAS OCCURRED FOR WHICH

ASSESSMENTS ARE NEEDED

NiMet has a role in the occurrence and

monitoring of floods

NiMet’s Role in the Project


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The Nigerian Meteorological Agency at a glance

The Agency is under the Ministry of Transportation (Aviation) and is

headed by a Director General who is appointed by the President of the Federal Republic of Nigeria and assisted by seven Directors all

appointed by the Minister with the approval of Mr. President.

Directorates: Weather Forecasting; Applied Meteorological Services; Engineering and

Technical Support; Research, Development and Training; Finance and Accounts; Legal

Services; and Administration and Supply

Established in 2003 and took off on the 19th day of the same

month and year.

Among its key functions, especially those related to this

stakeholder meeting are:

i. advise the Federal Government on all aspects of

meteorology;

ii. project, prepare and interpret Government policy in the

field of meteorology;

iii. issue weather forecasts for the safe operation of

aircrafts, ocean going vessels and oil rigs;

iv. promote the services of meteorology in agricultural,

drought and desertification activities;

v. provide meteorological services in operational hydrology

and water resources activities;


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NiMet’s Operations• Maintains a network of over 150 stations (some of which are at the airports) across the country for the

purpose of providing earth observations and issuance of meteorological advisories to Governments and their agencies, at the Federal, State and Local Government levels.

• Utilizes satellites, as source of information verified by synoptic observations from its stations, for research, training and development.

• Develops products, like the Seasonal Rainfall Prediction (SRP), that inform all stakeholders and the general public on the weather outlook for the year in all locations of the country.

• Develops partnerships and co-operation with Governments (States and Local Governments), Non-Governmental Organizations and, with individual Institutions and Agencies of the Federal Government whenever the need arises.

• Supports students at all levels with meteorological information (especially in the provision of quality data) in research during their studies, at a very subsidized cost.

• Champions the appreciation of meteorology at the primary and secondary levels by accepting students on excursion visits and through supporting schools' clubs that have science as their core area of interest.

• Represents Nigeria in the World Meteorological Organization (WMO)


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Distribution of NiMet Stations in Nigeria


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NIMET’S PRODUCTS ON FLOOD FORECASTING AND MONITORING

SEASONAL RAINFALL PREDICTION (SRP)

THE DROUGHT AND FLOOD

MONITORING BULLETIN (DFMB)

THE INTENSITY DURATION

FREQUENCY CURVES (IDF).

THE PROBABLE MAXIMUM

PRECIPITATION (PMP)


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THE SRP

The SRP is the major tool/product of NiMet, that is issued annually to forecast weather and

climate across the country to guide policy and decision makers of Governments (the three

tiers) and other stakeholders in making decisions, that depend on weather variability

and climate change, from an informed position

Key sectors that benefit from the SRP are: Agriculture, WaterResources, Health, Environment, Transportation, Communication,Education, Power and Energy, Construction, Tourism, Budget andPlanning, etc.

The information generated through the SRP can be used instrategic planning, climate-smart decisions and practices whichcould bring about reduction in the risk of losses from adverseweather, minimize disasters and maximize output.


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Key elements

of the SRP

i. Rainfall Onsetii. Rainfall Cessationiii. Length of Rainfall

Seasoniv. Dry Spell Periodsv. Annual Rainfall

Amountsvi. Day and Night

Temperatures


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THE SRP FOR WATER RESOURCES

Water management decisions depend on forecasts as provided by

the Seasonal Rainfall PredictionSuch decisions could be for meeting the demands for:

§ Domestic needs§ Agricultural needs§ Energy, transportation and

environmental sustainability§ Rivers water level monitoring and

analyses and flood management§ Dams management and reservoir

operations§ Irrigation and supplementary water

provision to augment the effects of dry spells


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TYPICAL PRESENTATIONS OF SRP FINDINGS


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2E 4E 6E 8E 10E 12E 14ELONG. (E)

2N

4N

6N

8N

10N

12N

14N

LAT.

(N)

ABE

ABK

ABU

AKU

ASAAWK

BAU

BEN

BID

CAL

ENU

GOM

GUS

IBAIJE

IKEIKO

ILOISE

JOS

KAD

KAN

KAT

LAF

LOK

MAI

MAK

MIN

OGJOND

OSD

OSG

OWE

PHC

SHK

SOK

UMUUYO

YEL

YOL

ZAR

USIAdo

DUT

MEAN MAXIMUM TEMPERATURE TMAX (Deg. C)

25

29

33

37

2E 4E 6E 8E 10E 12E 14ELONGITUDE

2N

4N

6N

8N

10N

12N

14N

LATI

TUDE

ABE

ABK

ABU

AKU

ASAAWK

BAU

BEN

BID

CAL

ENU

GOM

GUS

IBAIJE

IKEIKO

ILOISE

JOS

KAD

KAN

KAT

LAF

LOK

MAI

MAK

MIN

OGJOND

OSD

OSG

OWE

PHC

SHK

SOK

UMUUYO

YEL

YOL

ZAR

USIAdo

DUT

MAXIMUM TEMPERATURE ANOMALY

LEGEND

COLDER NORMAL WARMER

Normal defined by the toleranceof ±0.5 deg. Celsius departure

-2.5

-2 -1.5

-1 -0.5

0.5

1 1.5

2 2.5



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The Drought and Flood Monitoring

Bulletin (DFMB)

The DFMB is used for monitoring the degree of flood or drought as the case may be across the country and enables water resources managers, farmers and other relevant stakeholders in both public and private sectors to incorporate advisories issued in the bulletin

into their plans and operations.

The DFMB uses a set of indexes referred to as Standardized Precipitation Index (simply referred to as SPI1, SPI3, SPI6 and SPI12 – 1-month, 3-months; 6-months; and, 12-months), as a

means of categorizing the degree of flood or drought at a location.

For any given month and location, the indexes are computed by generating the long-term mean (climatological mean) and standard

deviation of the month in question.Generally, the indexes compares the rainfall recoded in the location

of interest with is its corresponding long-term mean.


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Sample Presentation of

the DFMB: depicting the 6-months SPI for

Jan. – Jun. 2019

2 4 6 8 10 12 142

4

6

8

10

12

14

ABE

ABU

ADEAKU

ASAAWK

BAU

BEN

BID

CALEKE

ENU

GOM

GUS

IBA

IBI

IJEIKEIKO

ILOISE

JOS

KAD

KAN

KAT

LAF

LAG

LOK

MAI

MAK

MIN

NGU

OGOOND

OSG

OWEPOR

POT

SAK

SOK

UYOWAR

YEL

YOL

ZAR

-4

-2

-1.5

-1

-0.5

0.5

1

1.5

2

JANUARY- JUNE, 2019

WET

NES

SD

RY

NES

S

0 50 100 150 200KM

EXTREME

EXTREME

NORMAL

SEVERE

SEVERE

MODERATE

MODERATE

MILD

MILD

LONGITUDE (E)LA

TITUD

E (N

)


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THE INTENSITY DURATION

FREQUENCY CURVES (IDF)

q An IDF Curve or Intensity-Duration-Frequency

describes a relationship between Intensity,

duration and frequency of rainfall that can return at

defined time intervals referred to as return periods;

it is a tool that characterizes an area’s rainfall

pattern.

q The IDF is a very important tool for flood control

and abatement; urban drainage systems, etc., used

by Engineers, Hydrologists and other professionals

as a major input parameter to forecast flood

q Typically 2-, 5-, 10-, 25-, 50- and 100-year return

periods are shown on IDF curves.An example of IDF Curves developed for Enugu depicting

intensity over time for various return periods


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PROBABLE MAXIMUM PRECIPITATION (PMP)

Probable maximum precipitation (PMP) is the

maximum or greatest value of precipitation recorded for a given

duration over a given area and at a particular time of

the year.

Like the IDF, the estimated PMP values tend to repeat or re-occur at specific time intervals referred

to as return periods and are computed from historical daily

rainfall data collected at a specific rainfall monitoring station

The PMP estimates are used to calculate the PMF which are used as a standard for designs of Dams and other infrastructure vulnerable

to heavy floods


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An example of probable maximum precipitation for Lagos state is given below


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y = 0.0643x - 1.2536R² = 0.51044

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.519

81

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Standardised Rainfall Anomaly over Nigeria during the period 1981-2018 (based on 40 Meteorological Stations and 1981-2010 Normals)

Rainfall Anomaly Nigeria shows an increasing trend over the last 37 years


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Maximum Temperature Anomaly over Nigeria during the period 1981 – 2018 (37yrs)

y = 0.0552x - 1.0763R² = 0.37627

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

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Standardised Maximum Temperature Anomaly over Nigeria during the period 1981-2018 (based on 40 Meteorological Stationsand 1981-2010 Normals)


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Coastal flooding

Nigeria has a coastline of about 853km stretching from Lagos to Calabar. A significant fraction of the country’s population (about

25%) live in the zone and it is estimated that up to about 75% of

Nigeria’s industrial establishments are located

around the coast and therefore much of Nigeria’s economic

activities takes place in this area.

Storm surges and coastal inundations as a result of sea level rise and overland flow respectively lead to:

Coastal flooding and Coastal erosion resulting in colossal loss of lives

and property


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y = 0.0594x - 1.1587R² = 0.43606

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

1981

1983

1985

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1999

2001

2003

2005

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2009

2011

2013

2015

2017

Standardised Maximum Temperature Anomaly over SouthernNigeria during the period 1981-2018 (based on 20 MeteorologicalStations and 1981-2010 Normals)

y = 0.0484x - 0.9434R² = 0.28905

-3

-2.5

-2

-1.5

-1

-0.50

0.51

1.52

2.5

1981

1983

1985

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1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

2011

2013

2015

2017

Standardised Rainfall Anomaly over Southern Nigeria during theperiod 1981-2018 (based on 20 Meteorological Stations and 1981-2010 Normals)

Rainfall and Maximum Temperature Anomalies over southern Nigeria over a period of 37 years –depicts similar rises with those of the country

Deduction – coastal flooding will continue to be a big issue due to increased rainfalls and temperatures. Temperature increases have been proven to raise sea levels and to cause

increase in sea surges.


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0

2

4

6

8

10

12

14

16

1994 1995 1996 1998 2000 2001 2002 2004 2006 2007 2012

Surge Occurences in V.I and Lekki, Lagos (1994 - 2012)

WaveHeight(m) No.ofOccurences

Wave Heights (m) and number of occurrences (days) of flooding due to surges in V.I and Lekki, Lagos.


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q Hope the presentation has been able to demonstrate how useful

NiMet’s forecasting and monitoring tools can be powerful in predicting

and managing floods in Nigeria.

q Stakeholders are urged to utilize the tools presented, and many others

that time could not permit demonstrating, in the design of

infrastructure that are vulnerable to flooding.

q Environmental Managers are also urged to use NiMet’s predictions,

developed with the presented tools, to strive to prevent flooding so as

to reduce the eventual resort to managing them in a “fire-brigade”

manner.

CONCLUSION


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For further details please visit:

www.nimet.gov.ng

THANK YOU FOR LISTENING

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