Notice to Data Users: The documentation for this data set was provided solely by the Principal Investigator(s) and was not further developed, thoroughly reviewed, or edited by NSIDC. Thus, support for this data set may be limited. The SMEX04 Soil Characteristics data set contains data for Arizona, USA as part of the 2004 Soil Moisture Experiment (SMEX04). The original data were extracted from a ... multi-layer soil characteristics database for the conterminous United States and generated using Environmental Systems Research Institute (ESRI) ArcMap software for the regional study area. Parameters for this data set include available water capacity, bulk density, elevation, permeability, porosity, rock fragment class, rock fragment volume, texture class, texture/percent clay, and texture/percent sand. The temporal coverage is approximate, as these data are representative of the conditions present in the regional study area during the general timeline of the SMEX04 campaign. The total volume for these data is approximately 635 megabytes. 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.