This data set includes soil moisture data measured with Delta-T Devices’ ThetaProbe ML2 sensors for the Soil Moisture Experiment 2003 (SMEX03), conducted during June and July 2003 in northern Alabama and southern Tennessee, USA. The output parameters include voltage readings from the probe and volumetric soil moisture calculated from the measured voltage. Data were collected at crop, pasture, and ... forested sites. Data are provided in either a Microsoft Excel spreadsheet file or in three 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.