In situ soil moisture network for validation of remotely sensed data

An automated soil moisture network for continuous measurement of soil moisture in the top 30 cm of the soil over an 8000 km² region has been established. The network consists of 32 stations encompassing a diversity of soil types. The measurements are being used to improve drought, flood, and agronomic production forecasts. In addition, the data are being used to examine the accuracy of remotely sensed measurements of soil moisture and the degree to which they represent natural variability across the landscape. The data were used to evaluate soil moisture conditions during the SMEX03 experiment. The data are being used to support testing of AMSR, AMSR-E, PSR, and synthetic aperture radar (SAR) observations. Gravimetric samples were collected for the period from June 23, 2003 to July 2, 2003 for comparison to both the in situ network and the remotely sensed data. During the experiment, daily in situ soil moisture measurements were taken and plant and soil samples collected for oven drying and determination of moisture content. The automated network provided continuous in situ soil moisture measurements throughout the coverage area. A wide variation in soil moisture was observed both over the time period and from site to site