On the Consistency between GRACE, In-situ Observed and Modeled Terrestrial Water Storage

Abstract:

GRACE satellite-measured terrestrial water storage (TWS) data have been widely used to compare with both in-situ observed and modeled data since its launched in 2003. Close agreement between various TWS data sources have been reported across different parts of the world. Also, GRACE TWS data were also utilized to infer certain unmeasured terrestrial water storage components like groundwater by using auxiliary data often from hydrological modeling. However, the consistency among various sources of TWS data has seldom been evaluated in previous studies. Here, we address several significant advanced issues regarding the consistency of the comparison between GRACE and other observed or modeled TWS data, including (1) the mismatch in temporal aggregation, (2) the mismatch in spatial aggregation, (3) the representativeness of TWS components simulated by hydrologic models, and (4) the application of scaling factors and forward modeling in basin-scale applications, by using several case studies in global regions. The results of this study can be served as an indication of the uncertainty involved in the application and validation of GRACE data in large-scale hydrology, as well as a guidance for future utilization of GRACE data in constraining hydrologic model behaviors and helping model parametrization development.