Abstract:
Groundwater is the primary source of fresh water in India. The consumption of groundwater for irrigation and other anthropogenic uses has unsustainably increased during the past decade. Satellite gravity data from the Gravity Recovery and Climate Experiment (GRACE) provides vertically integrated estimates of terrestrial water storage (TWS). The assimilation of GRACE TWS observations within land surface models allow for partitioning of the TWS into each of the water storage components over land (i.e. groundwater, surface and root zone soil moisture, snow, and surface hydrology). Here, we assimilate GRACE TWS observations within the Goddard Earth Observing System Model, version 5 (GEOS-5) to investigate changes in the water cycle of India. The assimilation of GRACE identifies and quantifies the depletion of groundwater. In particular, it reveals changes to the other components of the water cycle such as surface and root zone soil moisture, snow and surface water. Further, synergies and changes in precipitation and evaporative fluxes are also investigated in relation to the depletion of the surface and groundwater storages.