Remote Sensing of Groundwater Storage Changes in Illinois Using GRACE (Gravity Recovery and Climate Experiment)
Abstract
Recent research has demonstrated that GRACE can be used to estimate total water storage changes (TWSC) in large river basins, evapotranspiration, continental discharges, and snow storage. In this study we propose to estimate groundwater storage change by using remote-sensed GRACE data. Regional groundwater storage changes in Illinois are estimated from monthly GRACE total water storage change (TWSC) data and in situ measurements of soil moisture for the period 2002-2005. Groundwater storage change estimates are compared to those derived from the observed soil moisture and groundwater well level data. The seasonal pattern and amplitude of GRACE-estimated groundwater storage changes track those of the in situ measurements reasonably well, although substantial differences exist in month-to-month variations. The seasonal cycle of GRACE TWSC agrees well with observations (correlation coefficient = 0.83), while the seasonal cycle of GRACE- based estimates of groundwater storage changes beneath 2 meters depth agrees with observations with a correlation coefficient of 0.63. As another independent estimation, the combined atmospheric and terrestrial water balance computation is performed to estimate TWSC. The water-balance estimated TWSC from 1984-2005 agrees well with the in-situ observations in Illinois with a correlation coefficient of 0.69. We conclude that (1) the GRACE-based method of estimating monthly to seasonal groundwater storage changes performs reasonably well at the 200,000 km2 scale of Illinois, and (2) the combined water-balance computation can be used to estimate TWSC at the regional scale larger than Illinois.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2007
- Bibcode:
- 2007AGUSM.H54A..01Y
- Keywords:
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- 1640 Remote sensing (1855);
- 1655 Water cycles (1836);
- 1829 Groundwater hydrology;
- 1833 Hydroclimatology