Calibration and Validation of the Soil Moisture Active Passive Mission with USDA-ARS Experimental Watersheds.

The Soil Moisture Active Passive Mission (SMAP) is a new NASA mission scheduled for 2014 that will provide a number of soil moisture and freeze/thaw products. The soil moisture products will span spatial resolutions from 3 to 36 km. Key to the validation and calibration of the satellite products are in situ soil moisture observations. Data from the currently available set of soil moisture observing sites and networks needs improvement if they are to be useful. There is a lack of standardization across networks regarding instrumentation and installation. Furthermore, there is a disparity in spatial scales between the point-scale in situ data (a few centimeters) and the coarser scale satellite products. SMAP has initiated activities to resolve these issues for some of the existing resources. The other challenge to soil moisture validation is the need to expand the number of sites and their geographic distribution.  Specific examples of how the calibration validation program can be implemented in existing resources will be taken from the activities of the USDA-Agricultural Research Service Soil Moisture Program.