The objectives of this study are to a) characterize spatial-temporal variability in surface (0-5 cm) soil moisture at the ESTAR footprint scale (0.8 km) over the SGP97 region; b) use this characterization in conjunction with field observations of variability within ESTAR footprints to explore the scaling behavior of soil moisture variations up to larger footprint scales; and c) compare scaled results to available satellite data. Gravimetric and impedance probe data will be used along with soil, vegetation, topographic, precipitation, and meteorological information to determine the local and regional processes controlling variations in surface moisture content. Relationships between variability and mean moisture content, derived from field observations during the experiment, will be used to scale footprint statistics to larger areas, including the 25-50 km scale associated with a potential global passive microwave mission. Results of this scaling study will have implications for the performance of larger-footprint sensors, and for the utility of using sparse soil moisture monitoring networks like the Oklahoma Mesonet as ground-truth sites