Technical Abstract: The Southern Great Plains 1997 Hydrology Experiment (SGP 97) took place in Oklahoma during June 16 - July 18. The objectives of SGP 97 included the examination of surface soil moisture and temperature using remote sensing at a range of scales; examination of the feasibility of estimating vertical profiles of soil moisture and temperature by combining ground measurements, ,remote sensing of the ground surface and modeling techniques; and evaluation of the influence of soil moisture on the local surface energy budget, and the influence of regional variability in the surface energy budget on the development of the convective boundary layer. In support of these objectives, ground measured and estimated soil moisture from three different locations in the SGP 97 study area were compared. Because ground measurements were needed to verify the algorithms used to produce remotely sensed estimates of soil moisture content, and to meet the general lobjectives of SGP 97 a series of instrument intercomparison sites were established. These comparisons were designed to increase understanding of the performance capabilities of the different measurement systems so that natural variability in soil moisture could be separated from differences in measurement technique. At one site, the Department of Energy and the Agricultural Research Service operated soil moisture monitoring stations using identical sensors. Although the two stations were located in a dense stand of grassland vegetation, and only separated by about 50 feet, the data indicated very different soil moisture contents. Differences in point and layer estimates of soil moisture content were observed at other comparison sites.