The Soil Moisture Experiment 2002 (SMEX02) took place in Ames, Iowa USA between 25 June and 12 July 2002. The NASA Land Surface Hydrology Data Archive maintains an archive of soils and land cover characteristics for SMEX02. SMEX02 studies are designed to evaluate the accuracy of AMSR-E soil moisture data specific to the SMEX02 study areas, and SMEX02 provided the unique opportunity to test ... microwave soil moisture retrieval over agricultural land cover. The Soils Database includes Environmental Systems Research Institute (ESRI) shapefiles containing geographic information such as railroads, roads, and stream locations; drainage features; political boundaries; and soil classifications. Data for the following 10 Iowa counties are included in this data set: Boone, Dallas, Franklin, Hamilton, Hardin, Jasper, Marshall, Polk, Story, and Wright. These data were created by appending existing county digital soils data provided by the Iowa Cooperative Soil Survey (ICCS) and clipping them by the SMEX02 project area boundary; thus, the dates of data acquisition are highly variable. The entire data set is 293 MB. Data are available via FTP. These data were collected as part of a validation study for the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E). AMSR-E is a mission instrument launched aboard NASA's Aqua Satellite on 04 May 2002. AMSR-E validation studies linked to SMEX are designed to evaluate the accuracy of AMSR-E soil moisture data. Specific validation objectives include assessing and refining soil moisture algorithm performance; verifying soil moisture estimation accuracy; investigating the effects of vegetation, surface temperature, topography, and soil texture on soil moisture accuracy; and determining the regions that are useful for AMSR-E soil moisture measurements.