The Potential for Groundwater Monitoring Using GRACE, InSAR and GPS

The task of managing groundwater resources globally is becoming increasingly more difficult due to exponential population growth and climate change. Remote sensing will provide the tools needed to monitor changes in groundwater on regional and global scales, allowing water storage observations to be made in areas of the world without proper infrastructure for ground-based monitoring systems, and leading to a greater understanding of the global water cycle. Currently, remote sensing of water resources is available via the Gravity Recovery And Climate Experiment (GRACE), Interferometric Synthetic Aperture Radar (InSAR), and other GPS networks, each with inherent strengths and limitations. Separating groundwater from other components of the water balance equation in the vertically integrated gravity signal provided by GRACE requires ancillary observation of precipitation, surface water, soil moisture, and evaporation. InSAR has greater capability of separating observations of different water storage components, yet is limited by issues of temporal decorrelation caused by changes in the land surface that do not affect GRACE. We present a preliminary proposal to integrate GRACE, InSAR, and other GPS networks to provide a comprehensive method of monitoring groundwater resources remotely.