Polar prediction servicesprovided by the

Bureau of Meteorology insupport of the Australian Antarctic program.

Dr Neil Adams, Centre for Australian Weather and Climate Research and the Antarctic Meteorological Section, Tasmania Antarctica Region, Bureau of Meteorology.

1. Overview of the service provision,

2. Forecasting systems supporting services,Observational systems,Satellite data,NWP systems,Display systems,

3. Capability gaps and future requirements.

Antarctica is ~ 14x106 km2, the AAT ~ 5.6x106 km2, Australia ~ 7.6x106 km2,

ROUTINE.

1. Station and field party forecasts (public weather style),

2. Marine forecasts for resupply and marine research vessels,

3. Boating forecasts for local area boating activities,

4. Extended (5 to 7 day) outlooks across areas of interest field and aviation logistical support,

5. Aviation support:Terminal Area Forecasts (TAF),Landing Area Forecasts (LAF) – same as TAF but no supporting observations),

Graphical Route Forecasts.Flight following weather watch.

AD HOC.

1. Search and Rescue,2. Medivac,3. Sea-ice analysis.

Control Panel Full detail view + overlays Legend(no units)

Scroll view

Legend(same geographic extent as ASAR)

OBSERVATIONAL SYSTEMS.

SURFACE:

OBSERVATIONAL SYSTEMS.

UPPER AIR:

Davis Station HRPT (L-Band) ReceivingStation.

Casey X-Band Receiving Station.

Satellite Systems.Satellite Systems.

Casey

Hobart

Davis

Mawson

McMurdo

Dumont d'Urville

DomeConcordia

McMurdo

Casey

AVHRR, MODIS and geostationary satellite data from MTSAT, FY2 and METEOSAT composited as an underlay to the polarLAPS MSLP and near surface wind flow data.

Numerical Weather Prediction Systems

Antarctic weather is dominated by the influence of the orography. Accurate Numerical Weather Prediction is heavily dependent on model resolution. Available models include:

ECMWF (~ 12.5 km global) - Europeanlocal access,UKMO (~ 40 km global) UK (ensemble),NCEP-GFS (~ 50 km global) USA local access,ACCESS-G (~ 80 km global) Australianlocal access,AMPS (~ 15 km pan Antarctica) USA USA web access,PolarLAPS (~ 27.5 km Antarctica/Southern Ocean) Australian Aust web access.

ECMWF is the European global model. Over Antarctica Australia only has access to near surface variables at a resolution of around 150 km and only between 40o and 180oE.

UKMO is the UK global model. Australia only has access to 125 km resolution data.

NCEP-GFS is the US Global Forecast System (GFS) and is freely available.

ACCESS-G is the new Australian global model based around the UKMO Unified Model, employing 4d-Var assimilation. It is currently running at a very coarse resolution.

The Antarctic Mesoscale Prediction System (AMPS) is a US system supporting the USAP and international Antarctic forecasters. It is based on the WRF model, with 3d-Var assimilation.

PolarLAPS is a polar-stereographic implementation of the Australian Limited Area Prediction System (LAPS), initialised with model output from the NCEP-GFS, (no data assimilation). PolarLAPS is now finished to be replaced with ACCESS-P (UKMO-UM based).

AMPS +24HR output for 12Z 14 Jan 2010(http://www.mmm.ucar.edu/rt/amps/)

polarLAPS (gfsLAPS version) +24HR output

for 12Z 14 Jan 2010

Display Systems.Display Systems.

The efficient and effective display and analysis of observational and NWP data is essential in any forecasting operation, particularly in supporting aviation operations across Antarctica.

These systems have the capability of quickly encapsulating the current state of the weather and the time evolution of weather systems.

The system used in Antarctic forecasting support is the Casey Antarctic Forecasting System (CAFeS).

Access to full 4-D NWP fields

Post processed fields such as model cloud diagnostics and cross-sections.

Route forecast system output:

Summary

The Tasmania Antarctica Region is responsible for weather forecasting support for the Australian Antarctic program,

A sparsity of observations places a heavy emphasis on satellite interpretation for weather watch and flight following services,

Efficient and effective use of NWP output through dedicated weather forecasting display systems is essential for the provision of weather forecasts for the AAp.

Casey

Dome Concordia

Capability gaps and future requirements.

Extensive area of liquidcloud at temperaturesdown to -31oC.

Observed cloud base6-8 oktas, no weather,RH% = 22%.

PolarLAPS RH%, cloud liquid and cloud ice water content variables.

RH%

Liquid water path

Ice water path

1. The cloud micro-physics used in polarLAPS is not tuned for the polar environment,

2. Assimilated low level moisture data is limited to the very sparse radiosonde network,

3. Low level relative humidities may not pick up significant areas of ice cloud,

4. How good are the liquid and ice water mixing ratios in NWP systems ?

5. How do we observe/verify Antarctic cloud properties ?

LOW CLOUD IS A SIGNIFICANT AVIATION RISK IN ANTARCTICA.

THERE IS A GROWING DEMAND FOR A SEA-ICE FORECASTING SYSTEM TO ASSIST INNAVIGATION,

SEA-ICE FORECASTINGSYSTEMS REQUIREACCURATE FORCINGFROM HIGH RESOLUTIONNWP SYSTEMS,

ACCURATE SEA-ICE CHARACTERISTICS ARENEEDED AS LOWERBOUNDARY CONDITIONSFOR THE NWP SYSTEMS.

THERE IS A NEED TODEVELOP AN ANTARCTICSEA-ICE FORECASTINGSYSTEM CLOSELY TIEDTO AN NWP SYSTEM.