Polar Winds from Satellite Imagers and Sounders

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Polar Winds from Satellite Imagers and Sounders
MODIS Winds Group Paul Menzel1, Jeffrey Key1,
David Santek2, Christopher Velden2, Lars Peter
Riishojgaard3 Sounder Winds Group Cheng-Zhi
Zou1, Mark DeMaria1, Jennifer Francis4, and Mike
Van Woert1 1Office of Research and
Applications, NOAA/NESDIS 2Cooperative Institute
for Meteorological Satellite Studies (CIMSS),
Madison 3NASA Global Modeling and Assimilation
Office 4Rutgers University
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Pierre Morel and Verner Suomi introduced WV
remote sensing
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Water Vapor Image from 1978 changed the way Earth
is viewed
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An example Meteosat wind set from FGGE
helped define atmospheric motions, but not in
polar regions
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Geostationary Satellite-Derived Winds

• Tracking cloud/water vapor features in time
  provides horizontal advection speed
• Brightness temperatures place features in three
  coarse layers (0-400, 400-700, and 700-1000mb)
• 3-hourly product overlaid upon continuous IR loop

Satellite Focus unites an ever growing
compilation of new technology in a common
theater, providing users with a one-stop
satellite shop. Where you are, what you need,
when you need it.
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MODIS 1 km WV images first ever
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Routine production of MODIS WV winds in 2003
Pre ops tests in 2002
500 hPa geo potential
North Atlantic
Europe
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Forecast Benefits
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More Polar Obs Improve Mid-latitude Forecasts
Propagation of analysis errors from the poles to
the midlatitudes in 500 hPa geopotential height
for 1 to 5 day forecasts. Solid blue shows
geopotential with MODIS winds dashed black is
Control without MODIS winds. Solid red show
positive differences (MODIS minus CTL), and thick
dashed blue show negative differences. 20 meter
positive differences near the Beaufort Sea
(north of Alaska) move southward. The 5-day
MODIS forecast verifies better.
NWP depends on obs polar winds fill obs void
(offset Siberian raob loss) during
hostility non-US obs may be withheld
improved fcsts of weather affects boating
(fishing), shipping routes, aircraft
refueling, evacuations
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Error Propagation to the Midlatitudes Snowfall
Accumulated snowfall forecasts, in mm water
equivalent, over Alaska on 03/20/02 (end of
animation period). At right is the snowfall from
the 5-day CTL forecast, below left is the
snowfall from the 5-day MODIS forecast, below
right is the snowfall from a 12-hr forecast for
verification. The CTL run produced spurious
snowfall in southern Alaska.
CTL
MODIS
TRUTH
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NWP Model Overlays
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MODIS winds filling observing system void Being
used operationally since Jan 2003
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MODIS Winds in NWP
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500 hPa Geopotential Northern Hemisphere MODIS WV
winds mitigate bust
VV 60h
7th Int. Winds Workshop Jun 2004
Alexander Cress
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USA 5 day fcst very sensitive to northern
latitudes
Figure courtesy of Rolf Langland, NRL Monterey
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Busts over North America sometimes (often) have
high-latitude origins h500 error in four models
on 28 Jun 04
Figure courtesy of Lars Peter Riishojgaard, GSFC
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Forecast Busts (GMAO)
Southern Hemisphere Extratropics
Arctic
Blue is forecast with MODIS winds red is control
run
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JCSDA showing positive impact especially
mitigating busts Operational NCEP utilization
planned early 2005
Impact of MODIS AMVs on the operational GFS
forecast at 500hPa (60S - 90S). (1 Jan 15
Feb 2004) the pink (dashed) curve shows the ACC
with (without) MODIS AMVs
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JCSDA showing positive impact especially
mitigating busts Operational NCEP utilization
planned early 2005
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3D display of impact of polar winds on GFS 84 hr
forecast of 400 hPa heights
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Impact of MODIS Winds on Hurricane Track Forecasts
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AVERAGE HURRICANE TRACK ERRORS (NM)
13.2  43.6 66.5 94.9 102.8 157.1 227.9 301.1 Cntrl
11.4 34.8 60.4 82.6 89.0 135.3 183.0 252.0 Cntrl MODIS
74 68 64 61 52 46 39 34 Cases ()
00-h 12-h 24-h 36-h 48-h 72-h 96-h 120-h Time
FREQUENCY OF SUPERIOR HURRICANE PERFORMANCE ()
48.9   31.0 44.8 36.5 39.6 39.1 28.2 29.4 Cntrl
51.1 69.0 55.2 63.5 60.4 60.9 71.8 70.6 Cntrl MODIS
74 68 64 61 52 46 39 34 Cases ()
00-h 12-h 24-h 36-h 48-h 72-h 96-h 120-h Time

• Percent of cases where the specified run had a
  more accurate hurricane position than the other
  run.
• Note These cases are for hurricanes in the
  subtropics.

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

• MODIS winds do not meet cut-off of EMC and most
  regional/limited area data assimilation systems.
  Possible solution Direct broadcast to
  high-latitude X-band station(s)
• Northern Hemisphere - Fairbanks (NOAA), Kiruna
  (ESA) Svalbard (EUMETSAT)
• Southern Hemisphere - McMurdo. Polar winds
  system development is in progress!

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