EOS Validation Program

Institution: National Space Science and Technology Center
                    Global Hydrology and Climate Center
                    320 Sparkman Dr.
                    Huntsville, Al 35805
Phone: (256) 961-7885
FAX: (256) 961-7885
E-mail: charles.laymon@msfc.nasa.gov

William Crosson (NSSTC)
Ashutosh Limaye (NSSTC)

February 2003
April 2004

We propose to utilize a coupled hydrologic/radiobrightness model (H/RM) to provide "best estimates" of footprint-scale mean volumetric soil moisture and TB at C and X bands with associated variance and confidence limits. This information will provide quantitative validation of AMSR-derived soil moisture and C and X band TB. We will perform this analysis at several times of year at several validation sites globally. The high spatial and temporal resolution of the model output relative to AMSR observations will permit us evaluate a.) the errors associated with using limited GSM data or point-scale measurements of soil moisture from network stations to estimate footprint-scale mean soil moisture, b.) the errors associated with asynchronous sampling times, and c.) the relationship between surface moisture (~1 cm) and profile moisture.These analyses are necessary to characterize the accuracy of the AMSR data products at footprint scale. By applying the H/RM in simulation mode we will assess the limits of roughness/soil/vegetation parameter values beyond which AMSR soil moisture retrievals are not possible. Comparison between these simulations and AMSR-derived TB will identify areas where subpixel-scale heterogeneity warrants the use of effective parameter values or regions where AMSR C and X band soil moisture retrievals are not feasible.