Transcript Document 7561140

Recent Innovations in Polar Winds:
Direct Broadcast Sites and Historical AVHRR Polar Winds
Research group:
Dave Santek - MODIS and AVHRR winds
Chris Velden - MODIS and AVHRR winds
Richard Dworak - Historical AVHRR winds
William 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
Troll (Norway)
Palmer Station (U.S.)
Casey (Australia)
MODIS Direct Broadcast Sites
Possible Direct Broadcast Sites in the Arctic
Station masks for
• Fairbanks, Alaska
• Tromsø, Norway
• Svalbard
Sites currently under consideration: Fairbanks, Alaska and Sodankylä, Finland
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.
http://stratus.ssec.wisc.edu/db
Current Products at McMurdo
and Tromsø (all MODIS):
Winds
Cloud mask*
Cloud pressure*
Cloud phase*
Total precipitable water*
Inversion strength
Inversion depth
Ice/snow surface temperature
Ice/snow albedo
Planned products:
Ice motion (MODIS + AMSR-E)
Ice age
Snow cover
Cloud optical properties
*IMAPP/MODIS Science Team products
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 hPa
Light Blue: 400-700 hPa
Magenta: 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
ERA40
Mean Wind Speed: 7.70 m/s
Speed Bias: 1.02 m/s
Direction Bias: 10.16º
Speed RMS: 5.65 m/s
AVHRR
Mean Wind Speed: 6.31 m/s
Speed Bias : -0.37 m/s
Direction Bias: -0.26º
Speed RMS: 5.04 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 Projects
MODIS 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)