The Oklahoma Mesonetwork consists of 114 environmental monitoring stations throughout the state of Oklahoma. Approximately half of these stations are currently equipped with Campbell Scientific 229-L heat dissipation sensors at 4 depths, from which continuous soil moisture estimates can be derived. Sensors will be installed in the remaining half of the network through 1999. There were 10 Mesonet stations equipped with the soil moisture sensors within the study area of the Southern Great Plains-97 (SGP-97) Hydrology Experiment during the experimental period. Soil moisture estimates from the near-surface (5 cm depth) sensors at those sites will be compared to estimates derived from the ESTAR passive microwave instrument flown during the SGP-97 experiment. Additionally, the Mesonet data are being analyzed to determine the degree to which the point-based measurements, acquired exclusively in native and non-native grasslands, are representative of the soil moisture of surrounding areas. The SGP-97 data set and study area provides a unique opportunity for this analysis because of the abundance of special, short-term in-situ soil moisture data sets as well as the remotely sensed data. Hopefully, these analyses will indicate the degree to which the Mesonet soil moisture estimates need to be adjusted or spatially extrapolated in order to provide soil moisture estimates representative of larger areas.