Soil Moisture Sensing Controller And optimal Estimator (SoilSCAPE): First Deployment of the Wireless Sensor Network and Latest Progress on Soil Moisture Satellite Retrieval Validation Strategies

We develop wireless sensor network, control system, and data analysis technologies for dynamic and near-real-time validation of space-borne soil moisture measurements, in particular those from the Soil Moisture Active and Passive (SMAP) mission. Soil moisture fields are functions of variables that change over time across the range of scales from a few meters to several kilometers. We develop sensor placement policies based on spatial statistics of soil moisture, and for each location, develop dynamic scheduling policies based on physical models of soil moisture temporal dynamics and microwave sensor models for heterogeneous landscapes. Furthermore, we relate the ground-based estimates of the true mean to the space-based estimates through a physics-based landscape simulator and statistical aggregation procedure. An energy-efficient integrated communication and actuation platform is developed and used to command the sensors and transmit their data to a base station in near-real time. Full-scale field experiments were initiated in August 2010 with the deployment of the first full-scale wireless sensor network in Canton, Oklahoma, using our custom-built Ripple-1 architecture. This paper summarizes the results of the field deployment, status of the landscape simulator, and plans for the next set of deployments using the next generation network architecture and nodes, called Ripple-2.