AMSRE Science Team 2008 Telluride 14-16 July 2008 Richard E.J. Kelly ( [email protected]) The impact of physical temperature on brightness temperature observations over snow for NASA’s AMSR-E Richard Kelly Richard Kelly Department of Geography Department of Geography University of Waterloo University of Waterloo Ontario, Canada Ontario, Canada Marco Tedesco Marco Tedesco City College of New York City College of New York - CUNY - CUNY New York, USA New York, USA Thorsten Markus & James Thorsten Markus & James Foster Foster NASA/GSFC, USA NASA/GSFC, USA AM SR -E S t.Louis C reek,C O 180 190 200 210 220 230 240 250 260 270 11/1/2002 12/21/2002 2/9/2003 3/31/2003 5/20/2003 D ate B rig h tn ess T em p era (K) 0 5 10 15 20 25 30 35 40 45 50 18V -36V (K xv36 xv18 xv18-xv36
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Richard Kelly Department of Geography University of Waterloo Ontario, Canada
The impact of physical temperature on brightness temperature observations over snow for NASA’s AMSR-E. Richard Kelly Department of Geography University of Waterloo Ontario, Canada Marco Tedesco City College of New York - CUNY New York, USA Thorsten Markus & James Foster NASA/GSFC, USA. - PowerPoint PPT Presentation
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AMSRE Science Team 2008Telluride 14-16 July 2008 Richard E.J. Kelly (
SummaryWhat causes apparent fluctuations in the SWE estimates
or Tb18-Tb36?•Contribution of Tair to Tbs at lower frequencies is greater than higher frequencies;•‘Surface’ temperature-related effects (driven by air temps) are a likely cause of Tb fluctuations;•Vegetation temperatures are likely to change with air temperature;•Vegetation emissivity changes are small (excepting snow in the canopy);
•Snowpack temperature variations Ts are not a likely cause;
•Ground temperature/emissivity variations are not a likely cause;•Snow emissivity changes in response to punctuated snowfall events and seasonal snowpack evolution but not at the time scale under consideration.
Conclusions & Further Work•We are looking at correcting for Ts & Tv in the retrievals.
•Can we estimate Tair from AMSR-E? (synergy w/ John Kimball). If achievable, Tair could be used to help drive a snowpack stratigraphy model (information needed in retrieval parameterization).•Other sites under test (Canada: tundra and Boreal forest; Russia).•A simple fix could be to ratio Tb18/Tb36 rather than subtract Tb18-Tb36•Validation of current version is in progress for Sept 2008 - refinement activity will follow.
AMSRE Science Team 2008Telluride 14-16 July 2008 Richard E.J. Kelly (