recent innovations in polar winds: direct broadcast sites and historical avhrr polar winds

Recent Innovations in Polar Winds: Direct Broadcast Sites and Historical AVHRR Polar Winds

Research group:

Dave Santek - MODIS and AVHRR windsChris Velden - MODIS and AVHRR windsRichard Dworak - Historical AVHRR windsWilliam Straka III - Direct broadcast products

MODIS Winds in NWP

Current Operational Users:

• European Centre for Medium-Range Weather Forecasts (ECMWF) - since Jan 2003.

• NASA Global Modeling and Assimilation Office (GMAO) - since 2003.

• Deutscher Wetterdienst (DWD) – since Nov 2003.

• Japan Meteorological Agency (JMA), Arctic only - since May 2004.

• Canadian Meteorological Centre (CMC) – since Sept 2004.

• US Navy, Fleet Numerical Meteorology and Oceanography Center (FNMOC) –since Oct 2004.

• UK Met Office – since Feb 2005.

• National Centers for Environmental Prediction (NCEP) and the Joint Center for Satellite Data Assimilation - since Nov 2005.

• Meteo France - since June 2006.

MODIS Polar Winds Real-Time Processing Delays - Frequency of Delays in Wind Retrievals

With an average delay of 3-5 hours, MODIS winds do not meet the 3-hr (or less) cutoff for early model runs.

Possible solution: Generate winds with direct broadcast data, either on- or off-site.

Processing times are for the middle image in a 3-orbit triplet. Actually processing time from image acquisition to availability of wind vectors is 100 minutes (1.67 hrs) less than shown.

McMurdo Station, Antarctica

The National Science Foundation installed an L/S/X-band ground station at McMurdo station in January 2005. The system is one of the first to be able to capture all telemetries available: L-band NOAA, S-band DMSP and X-Band AQUA/TERRA.

McMurdo MODIS Winds

MODIS winds system installed in November 2004. Antenna installed in January 2005. Wind production began in April 2005.

MODIS Data Acquisition Time

Bent-pipe McMurdo DB

Potential Antarctic Sites

Palmer Station (U.S.)

Casey (Australia)

Troll (Norway)

MODIS Direct Broadcast SitesPossible Direct Broadcast Sites in the Arctic

Sites currently under consideration: Fairbanks, Alaska and Sodankylä, Finland

Station masks for • Fairbanks, Alaska• Tromsø, Norway• Svalbard

Tromsø, Norway

A polar winds system was installed at Tromsø, Norway, at the Kongsberg Satellite Services (Ksat) facility in February 2006. The MODIS data are currently acquired with the Integrated Program Office (IPO, the NPOESS people) antenna on Svalbard. At present, wind generation if from Terra only and is irregular due to antenna scheduling issues.

Tromsø Winds

Operational Use by Fleet Numerical Meteorology and Oceanography Center

FNMOC began using the McMurdo DB winds in March (2006) and the Tromsø winds in April. For their early model runs (1:10 cutoff), the DB winds are often the only winds available for the polar regions.

Current Products at McMurdo and Tromsø (all MODIS):WindsCloud mask*Cloud pressure*Cloud phase*Total precipitable water*Inversion strengthInversion depthIce/snow surface temperatureIce/snow albedo

Planned products:Ice motion (MODIS + AMSR-E)Ice ageSnow coverCloud optical properties

*IMAPP/MODIS Science Team products

http://stratus.ssec.wisc.edu/db

Effects into the Mid- and Low-Latitudes

1000-500 hPa thickness differences (MODIS vs control) in a 120 hour forecast.

Alternating red and blue indicates differences in positions and/or intensities of troughs/ridges.

Historical AVHRR Polar Winds Project(Primarily the work of Richard Dworak)

Yellow: Below 700 hPaLight Blue: 400-700 hPaMagenta: Above 400 hPa

Data

– AVHRR (Advanced Very High Resolution Radiometer) Global Area

Coverage (GAC) at ~ 4 km for the time period 1981-2004 (24 years).

– It has 5 channels including visible, three shortwave (vis and near-IR) and two

thermal IR. There is NO water vapor channel. With MODIS winds, the WV

winds account for about 70% of the total number of wind vectors! Wind

derivation is based on cloud tracking in the 11 µm infrared window channel.

– Model background: ECMWF Reanalysis ERA-40.

AVHRR vs. ERA40 Winds: Arctic

Validation of AVHRR Winds: LeadEx LeadEx was a field experiment that took place in the Beaufort Sea from March 19 to April 21, 1992. The RAOB data from this project was not assimilated into the reanalysis field.

Mean Raob Speed: 6.68 m/s

AVHRRMean Wind Speed: 6.31 m/sSpeed Bias : -0.37 m/sDirection Bias: -0.26º Speed RMS: 5.04 m/s

ERA40Mean Wind Speed: 7.70 m/sSpeed Bias: 1.02 m/sDirection Bias: 10.16ºSpeed RMS: 5.65 m/s

● ~150 collocations, everything within 25 mb and 75 km.● Results are for all vectors lower (in altitude) than 400 hPa.

Status of MODIS and AVHRR Wind ProjectsMODIS Winds, General• Mixed satellite (Terra and Aqua) processing is being almost ready for testing.• A parallax correction has been implemented and is being tested. Computational efficiency is an issue.• Dave Santek is working hard to explain the global impact. Before long he will be PHinisheD at last!

Direct Broadcast Winds• A MODIS wind system will be installed at Sodankylä, Finland later this year (Terra only). Fairbanks,

Alaska is also a probable site (Aqua only). Troll, Antarctica (Norway) is a distinct possibility.

Historical AVHRR Winds• The historical AVHRR winds data set should be completed by fall of this year. Done now: Arctic

1990-2002; Antarctic 1997-1999, 2001-2002• ECMWF, GMAO, and JMA have shown interest in assimilating the AVHRR wind data into future

reanalysis products. • We are creating combined AVHRR-TOVS and MODIS-AIRS (thermal wind) data sets (with J.

Francis, Rutgers Univ., and C.-Z. Zou, NESDIS)