Groundwater Storage Changes: Present Status from GRACE Observations

Abstract

Satellite gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) provide quantitative measurement of terrestrial water storage (TWS) changes with unprecedented accuracy. Combining GRACE-observed TWS changes and independent estimates of water change in soil and snow and surface reservoirs offers a means for estimating groundwater storage change. Since its launch in March 2002, GRACE time-variable gravity data have been successfully used to quantify long-term groundwater storage changes in different regions over the world, including northwest India, the High Plains Aquifer and the Central Valley in the USA, the North China Plain, Middle East, and southern Murray-Darling Basin in Australia, where groundwater storage has been significantly depleted in recent years (or decades). It is difficult to rely on in situ groundwater measurements for accurate quantification of large, regional-scale groundwater storage changes, especially at long timescales due to inadequate spatial and temporal coverage of in situ data and uncertainties in storage coefficients. The now nearly 13 years of GRACE gravity data provide a successful and unique complementary tool for monitoring and measuring groundwater changes on a global and regional basis. Despite the successful applications of GRACE in studying global groundwater storage change, there are still some major challenges limiting the application and interpretation of GRACE data. In this paper, we present an overview of GRACE applications in groundwater studies and discuss if and how the main challenges to using GRACE data can be addressed.

A global reconstruction of climate‐driven subdecadal water storage variability

“…In this way, the uncertainty related to the removal of the subdecadal climate-driven signal is directly propagated to the uncertainty of the trend estimate. Note that the trend magnitudes reported in Figure 3b do not represent actual depletion rates as they do not account for signal attenuation, which can easily be as high as 50% for this region as shown in previous assessments [Rodell et al, 2009;Chen et al, 2014Chen et al, , 2016.…”

“…At each temporal scale, some processes may be more relevant than others. For example, decadal trends can be controlled by groundwater depletion [Döll et al, 2014;Chen et al, 2016] or ice melt [Jacob et al, 2012;Velicogna et al, 2014], whereas short-term anomalies are usually related to fluctuations of the relevant atmospheric drivers [Humphrey et al, 2016]. We therefore decompose the TWS signal in order to relate changes in water storage to changes in atmospheric drivers at the temporal scales at which they are the most relevant.…”

Characterizing Drought and Flood Events over the Yangtze River Basin Using the HUST-Grace2016 Solution and Ancillary Data

“…It has been validated in Greenland [31,32], Northwest India [33], West Antarctica [34] and Tonle Sap Basin [16]. To assess its efficiency in the YRB, the CSR RL05 mascon solution and GRACE Tellus monthly mass grids were introduced for comparison.…”

Groundwater Variations From Autocorrelation and Receiver Functions

“…Gravity data can be used to infer changes in mass balance due to hydrological variations in regional-(e.g., Rodell et al, 2009) and local-scale aquifers (e.g., Chen et al, 2016;Rodell et al, 2007;Strassberg et al, 2007;Swenson et al, 2006;Yeh et al, 2006). Gravity data can be used to infer changes in mass balance due to hydrological variations in regional-(e.g., Rodell et al, 2009) and local-scale aquifers (e.g., Chen et al, 2016;Rodell et al, 2007;Strassberg et al, 2007;Swenson et al, 2006;Yeh et al, 2006).…”