GRACE satellite observations of terrestrial moisture changes for drought characterization in the Canadian Prairie

SummaryThe essence of this paper is to undertake an investigation of the recent Canadian Prairie drought by employing total water storage anomalies obtained from gravity recovery and climate experiment (GRACE) remote sensing satellite mission. In order to successfully retrieve average terrestrial water storages from gravity measurements, a necessary procedure is to undertake the transformation of the GRACE geopotential spherical harmonic coefficients into spatially varying time series of geopotential heights that were subsequently converted into water equivalent amounts. These obtained GRACE-based total water storages were thereafter validated using storages estimated from the atmospheric-based water balance P − E computation in conjunction with the measured streamflow records for the Saskatchewan River Basin at its Grand Rapids outlet in Canada. Interestingly, the results from this study corroborate the potential of GRACE-based technique as a veritable tool for the characterization of the 2002/2003 Canadian Prairie droughts. Especially, this approach would prove resourceful for other regions globally where soil moisture availability is sparing or worst still, inexistent thereby making such studies impossible.