Centre d’applications et de recherches en télédétection
Kalifa Goïta, Mehdi Eshaghi
Improving and downscaling GRACE and GRACE-FO data for the retrieval of terrestrial water storage and groundwater storage changes at finer scale
The main objective of my research was to improve the estimation and spatial resolution of TWS and related groundwater storage changes (GWS), using the twin satellite systems of Gravity Recovery And Climate Experiment (GRACE) and its successor, GRACE Follow-On (GRACE-FO) data. This challenge was addressed through four specific objectives, where original approaches were developed in each case.
The first objective was to understand and better take into account the uncertainties associated with the hydrological models (the Global Land Data Assimilation System (GLDAS), and the Water Global Assessment Prognosis hydrological model (WGHM)), generally used in the processing of GRACE or GRACE-FO data. The second specific objective was to understand regional variations in TWS and their uncertainties. The third objective was to extract GWS component using a comprehensive rigorous approach to reconstruct, refine and map the variations of GWS and its associated uncertainties. Finally, the last objective was to improve the spatial resolution of the results extracted from GRACE data from 1° to 0.25°.