Groundwater Storage Depletion in the Northwest India Aquifer using Forward Modeling and GRACE Satellites

Monday, 15 December 2014
Di Long, University of Texas at Austin, Bureau of Economic Geology, Jackson School of Geosciences, Austin, United States; State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing, China, Bridget R Scanlon, Univ Texas Austin, Austin, TX, United States and Jianli Chen, Center for Space Research, University of Texas at Austin, Austin, TX, United States
Signal restoration of GRACE total water storage (TWS) and groundwater storage (GWS) changes for aquifers is challenging because human-induced water storage changes are often not simulated and have large uncertainties in land surface models (LSMs). This study demonstrates the effectiveness of forward modeling for restoring GRACE signal loss due to low-pass filtering applied to GRACE data. A new approach integrating the strengths of LSMs and forwarding modeling is developed to recover TWS and GWS changes using the North India Aquifer as a case study. GWS for a broad region of North India (~1,000,000 km2) during the past decade (Jan 2003-Jan 2013) showed a generally consistent decreasing trend at a rate of -2.1 cm/a (-22. 3 km3/a), and GWS changes for the three-state region (Punjab, Haryana & Delhi, and Rajasthan, 436,390 km2) for the period Jul 2003-Jul 2008 was estimated to be -2.9 cm/a (-12.7 km3/a). This study provides new insights into GRACE signal restoration for TWS and GWS estimation over aquifers.