EMERGING GROUNDWATER STORAGE TRENDS FROM GRACE AND CONTRIBUTIONS TO GLOBAL MEAN SEA LEVEL RISE

Over the last decade, advances in satellite remote sensing are providing new means for monitoring groundwater storage changes in the world’s large aquifer systems. Specifically, NASA’s Gravity Recovery and Climate Experiment (GRACE) mission provides monthly data on terrestrial water storage changes (i.e. for all of the snow, surface water, soil moisture and groundwater) in regions of at least 200,000 square kilometers. Combining GRACE data with independent observations of snow, surface water and soil moisture has proven to be an effective means of characterizing groundwater storage changes. In this presentation, the GRACE-based methodology will be reviewed, and groundwater storage changes in the world’s major aquifer systems will be presented. We find that many of the world’s major mid-latitude aquifers are being depleted, posing new challenges for sustainable water management. Although our results are consistent with observations of alpine glacial melt and groundwater depletion around the world, we find that water losses from these regions are compensated by storage gains at high and low latitudes. Hence for the period of the GRACE record studied (2003-2013), we find that that land contributions to global mean sea level rise are not significantly different from zero.