EGU2020-2692
https://doi.org/10.5194/egusphere-egu2020-2692
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Fast determination of surface water mass changes using regional orthogonal functions

Guillaume Ramillien1 and Lucia Seoane2
Guillaume Ramillien and Lucia Seoane
  • 1Géosciences Environement Toulouse UMR 5563, CNRS, Observatoire Midi-Pyrénées, Toulouse, France (guillaume.ramillien@get.omp.eu)
  • 2Géosciences Environement Toulouse UMR 5563, Université Paul Sabatier Toulouse III, Observatoire Midi-Pyrénées, Toulouse, France (lucia.seoane@get.omp.eu)

Approaches based on Stokes coefficient filtering and « mass concentration » representations have been proposed for recovering changes of the surface water mass density from along-track accurate GRACE K-Band Range Rate (KBRR) measurements of geopotential change. The number of parameters, i.e. surface triangular tiles of water mass, to be determined remains large and the choice of the regularization strategy as the gravimetry inverse problem is non unique. In this study, we propose to use regional sets of orthogonal surface functions to image the structure of the surface water mass density variations. Since the number of coefficients of the development is largely smaller than the number of tiles, the computation of daily GRACE solutions for continental hydrology, e.g. obtained by Extended Kalman Filtering (EKF), is greatly fastened and eased by the matrix dimensions and conditioning. The proposed scheme of decomposition is applied to the African continent where it enables to very localized sources of (sub-)monthly water mass amplitudes.

How to cite: Ramillien, G. and Seoane, L.: Fast determination of surface water mass changes using regional orthogonal functions, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2692, https://doi.org/10.5194/egusphere-egu2020-2692, 2020

Displays

Display file