The 2006 Australian drought detected by GRACE

We detected the TWS (Terrestrial Water Storage) changes induced by the 2006 Australian drought from the GRACE satellite gravity data. The GRACE data showed significant TWS decrease at southeast Australia in 2006 where historic rainfall deficiency was reported. We compared the GRACE data with those of hydrological models; the GLDAS model and the JLG model. Although the hydrological models indicated TWS decrease in 2006, those amplitudes were much smaller than the GRACE estimation. This suggests that the hydrological models do not properly recover the landwater storage changes caused by the drought. We consider the precipitation data inputted to the hydrological model and/or the land surface model caused the underestimation of the TWS changes induced by the drought. Our results demonstrated that GRACE can provide not only large-scale annual landwater variation but also landwater response to interannual climate changes and it will make great contribution to understand the climate impacts to water resources.