The parameters for this data set include gravimetric and volumetric soil moisture, bulk density, and soil temperature. This data set is part of the Soil Moisture Experiment 2002 (SMEX02). The SMEX studies are designed to evaluate, among other things, the accuracy of AMSR-E soil moisture data. This study was conducted during June and July 2002 in the area around Ames, Iowa, USA. Data were ... collected in crop fields using a variety of methods and sensors: manual soil samples for gravimetric and bulk density data, infrared pyrometers for soil moisture, and hydra probes for soil moisture and temperature. Data are provided in ASCII text files, and 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.