06 dec 2006wmo cimo teco-2006 an historical view of adaptive observing strategies in australia wmo...

06 Dec 2006 WMO CIMO TECO-2006

An Historical View of Adaptive Observing Strategies in Australia

WMO CIMOTECO-2006

Russell Stringer

Australian Bureau of Meteorology

[email protected]


An Historical View of Adaptive Observing Strategies in Australia

Introduction

Adaptive Surface Observations

Adaptive Upper Air Observations

Adaptive Radar, Satellite Observations

Some events: Tropical Cyclone; upper level trough

Conclusion


Introduction

An adaptive observing strategy:

o Implements variations to a routine programme of observations;

o Based on meteorological conditions or other contingencies;

o May target additional observations in situations of high expected value;

o May tolerate reduced observations in situations of low expected value….


Introduction – Australian contextUpper Air stations.



Tropical Cyclone “Emergency Reporting Network” (ERN)



Storm Spotters network:

o Concentrated over eastern and southern parts of Australia

• Greatest population

• Greatest impact of severe TS;

o Volunteers are provided with training material and other references;

o Reports are made when the weather requires it



Australian Volunteer Observing Fleet (AVOF)

“REMARKS

Ships in the general area please transmit 3-hourly weather reports.”



Automatic Weather Station (AWS) observations: configuration flexibility enables adaptable operations:

o Message format choices;

o Frequency of generating each required message type;

o Frequency of storage;• Data stored in the AWS logger, may be reconfigured to higher

storage rates during significant events;

o Frequency of transmission;• This is the most commonly adjusted item, including seasonal

changes and event based adjustments;

o Remote interrogation, polling for data.


Adaptive Surface Observations Portable AWS

o Flexible in space as well as time

o Ability to register location in station dictionary => data into applications

o “Fire weather trailer” joint project


Adaptive Upper Air Observations 50 Australian Upper air stations have a mix of technology and

observing programs:o 31 track balloons by Radar;

• 7 use two radiosondes per day (00 and 12 UTC) and report wind-only data at 06 and 18 UTC.

• 14 use one radiosonde per day (00 UTC) and report wind-only data at other times, mostly 06 and 12 UTC.

• 10 never use radiosondes, reporting wind only.

o 17 track balloons by GPS;• 13 Vaisala™ Autosonde© stations;

• 4 manual balloon release.

o 2 operate only a BLP

Hence a mix of cost/opportunity for

adaptive flights (wind only, radiosonde)



Two developments in the upper air network led to the introduction of a systematic program of adaptive radiosonde flights:

o mid 1990’s: progressive introduction of 12 (now 13) Autosonde units => loss of 06/18 UTC wind only flights

o January 2005: reduction in overall usage of radiosondes => implemented as a substantial reduction in 12 UTC program across the network



Adaptive radiosondes flown per month at Australian upper air stations 2001-2006

0

20

40

60

80

100

120

Dec-0

1

Feb-0

2

Apr-0

2

Jun-

02

Aug-0

2

Oct-0

2

Dec-0

2

Feb-0

3

Apr-0

3

Jun-

03

Aug-0

3

Oct-0

3

Dec-0

3

Feb-0

4

Apr-0

4

Jun-

04

Aug-0

4

Oct-0

4

Dec-0

4

Feb-0

5

Apr-0

5

Jun-

05

Aug-0

5

Oct-0

5

Dec-0

5

Feb-0

6

Apr-0

6

Jun-

06

Aug-0

6

numberflown

numberallocated



A tropical cyclone is developing off the coast. Do we need more flights

to monitor it?

Instruction to Observing Office to perform additional flight

yes



Number of adaptive radiosondes, Jan 05 to Sep 06, by attributed category

020406080

100120140160180200

tropic

al cy

clone

signi

fican

t/sev

ere

weath

er

uppe

r lev

el tr

ough

fire

weath

erfro

nt

mon

soon

trou

gh

east

coas

t low

Antar

ctic

sum

mer

flying

ope

ratio

ns

test

ing, t

rain

ing

relat

ed

repa

ir, m

ainte

nance

rela

ted



Other adaptive approaches to upper air obs:

o Portable balloon launch and tracking facility

o Aircraft-based approaches• Cold Fronts Reconnaissance

program, 1991-93

• Aerosonde

• AMDAR


Adaptive Radar, Satellite Observations Weather surveillance by radar was

originally a manual task for on-site observing staff:

o Performed PPI and RHI scans to compose a RAREP:

• Text message describing areas of low, medium, high reflectivity and height of significant cloud tops;

o later a hand drawn map was faxed to the forecasting office;


Adaptive Radar, Satellite Observationso The level of weather surveillance by radar was

inherently adaptive to the prevailing weather, and supported intensive applications such as:

• Aerodrome terminal area thunderstorm service;

• Terminal area severe turbulence nowcasting;

• Cyclone tracking;

Replaced by PC in forecast office providing dialup access to digital data, data display and manipulation:

o Forecaster could decide and implement more/less frequent dialup during active/inactive weather;

o Tension with cost of communication services.


Adaptive Radar, Satellite Observations Now there is little control of the radar by a forecaster.

A volumetric scan every 10 minutes provides data for the forecaster to view/manipulate on their workstation;

A few radars still provide only composite-PPI images, then switch to volumetric mode during active weather;

The days of adaptive strategies are giving way to consistency and standardisation:

o For community access to stable 10-minute images;

o For automatic and quantitative applications (rainfall estimation, cell tracking, severe thunderstorm feature detection, …….).


Adaptive Radar, Satellite Observations The Australian Bureau of Meteorology

has gained enormous benefit for many years from access to data from the Geostationary Meteorological Satellite of the Japan Meteorological Agency, and more recently the MTSAT.

During the 1980’s the standard frequency of provision of satellite images was 3-hourly. However an arrangement was in place allowing provision of hourly images during emergencies, for limited durations. The situation most likely to trigger this provision was a tropical cyclone.


Tropical Cyclone events

Severe Tropical Cyclone Monica – April 2006



Source: MTSAT of JMA



TC Monica – Network coverage

Regular surface network (pink, green dots)

Upper air stations (red)

Radar coverage (faint yellow)

A technician was flown to Gove station for radar etc systems support

49 extra radiosondes, many extra wind-only flights

North coast AWS frequency


Severe Tropical Cyclone Ingrid – March 2005

o Similar track to Monica

o Observer and technician sent to Gove observing office

o ERN activated (3 regular observers, 2 additional observers)

o AWS frequency increased (to half hourly)

o MV Warrender (freight barge) sent 38 invaluable hourly obs while en route to, and at, Raragala Island where it sought refuge from the cylone – and reported 90 knot winds



•


Conclusion

The ability to operate and gain advantages from adaptive observing strategies relies on:

o Ability to implement variations to the routine program:

• Temporal variations – incremental cost/effort

• Spatial variations – specialised mobile capability (hazard/value at risk)

• Manual program – location, safety, training

• Automatic program – design, configuration

• Cost of communications – routinely a significant factor

o Ability to decide on variations:• Senior Meteorologist: best “situational awareness” of value/capability

• enabling framework: policy, preparations, resources, flexibility/control

• Future: objective guidance for maximum impact on NWP system?


Conclusion

A significant weather situation is developing …..

Do we need more radiosonde flights to monitor

it? Instruction to Observing Office to perform additional flight

yes

What NWP impact?


Thank you….

Questions?

06 dec 2006wmo cimo teco-2006 an historical view of adaptive observing strategies in australia wmo...

Documents

upper air network

reduced observations

report wind

hourly weather reports

track balloons

station dictionary

aws logger

mix of technology