Submitted to: Geoscience and Remote Sensing Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/9/2008
Publication Date: 12/22/2008
Citation: Jackson, T.J., Cosh, M.H., Bindlish, R. 2008. A five-year validation of AMSR-E soil moisture products. In: Proceedings of the International Geoscience and Remote Sensing Symposium, July 7-11, 2008, Boston, Massachusetts. p. II69-II72. Interpretive Summary:
Technical Abstract: Soil moisture products from the Advanced Microwave Scanning Radiometer (AMSR-E) must be validated because the retrieval algorithms utilize formulations, parameters and ancillary data that have not been thoroughly developed and verified. Validation of satellite-based soil moisture algorithms and products is particularly challenging due to the disparity of scales between the satellite observations and conventional ground based measurements of soil moisture. It is further complicated by the multiple scales of variability of the soil moisture field related to geographic units defined by land cover, soils, and topography, and as the result of rainfall events and climate. Validation programs for the AMSR-E instrument on the NASA Aqua satellite were incorporated into both the NASA and JAXA programs. As part of the AMSR-E validation activity several networks of in-situ soil moisture sensors were established using the existing infrastructure of research watersheds in the U.S. These networks provide estimates of the average soil moisture over the watersheds and surrounding areas that approximate the size of the AMSR-E passive microwave footprint. Four watersheds in different vegetation/climate regions of the U.S. were selected. In this investigation, the soil moisture products available from NASA and JAXA are compared to the watershed averages for the period of 2002-2007. In addition, retrievals from an alternative soil moisture algorithm are included for comparison. A caveat on these results is that both NASA and JAXA have been introducing changes to both the brightness temperature and soil moisture products that have not been fully incorporated into the databases. Therefore, the results presented here are not final. The results indicate that each algorithm has different performance statistics that depend upon the site. A positive outcome of the analysis is that it appears that the algorithms have the potential to perform within acceptable error bounds.