GHYRAF (Gravity and HYdrology in AFrica): a New Experiment Combining Hydrology and Geodesy to Investigate Water Storage Changes from the Sahara to the Equatorial Monsoon Zone.

HR: 0800h
AN: H31A-0123 [Abstracts]
TI: GHYRAF (Gravity and HYdrology in AFrica): a New Experiment Combining Hydrology and Geodesy to Investigate Water Storage Changes from the Sahara to the Equatorial Monsoon Zone.
AU: de Linage, C
EM: caroline.de-linage@eost.u-strasbg.fr
AF: IPG Strasbourg (UMR7516-CNRS/ULP), 5 rue Rene Descartes, Strasbourg, 67084, France
AU: * Hinderer, J
EM: jhinderer@eost.u-strasbg.fr
AF: IPG Strasbourg (UMR7516-CNRS/ULP), 5 rue Rene Descartes, Strasbourg, 67084, France
AU: Boy, J
EM: jpboy@eost.u-strasbg.fr
AF: IPG Strasbourg (UMR7516-CNRS/ULP), 5 rue Rene Descartes, Strasbourg, 67084, France
AU: Masson, F
EM: frederic.masson@eost.u-strasbg.fr
AF: IPG Strasbourg (UMR7516-CNRS/ULP), 5 rue Rene Descartes, Strasbourg, 67084, France
AU: Gegout, P
EM: pgegout@eost.u-strasbg.fr
AF: IPG Strasbourg (UMR7516-CNRS/ULP), 5 rue Rene Descartes, Strasbourg, 67084, France
AU: Diament, M
EM: diament@ipgp.jussieu.fr
AF: IPG Paris, 4 place Jussieu, Paris, 75252, France
AU: de Viron, O
EM: deviron@ipgp.jussieu.fr
AF: IPG Paris, 4 place Jussieu, Paris, 75252, France
AU: Bayer, R
EM: roger.bayer@dstu.univ-montp2.fr
AF: Geosciences Montpellier, 4 place Bataillon, Montpellier, 34095, France
AU: Balmino, G
EM: balmino@dtp.obs-mip.fr
AF: DTP, OMP 14 avenue Belin, Toulouse, 31400, France
AU: Biancale, R
EM: biancale@dtp.obs-mip.fr
AF: DTP, OMP 14 avenue Belin, Toulouse, 31400, France
AU: Bonvalot, S
EM: bonvalot@lmtg.obs-mip.fr
AF: LMTG, OMP 14 avenue Belin, Toulouse, 31400, France
AU: Genthon, P
EM: genthon@msem.univ-montp2.fr
AF: Hydrosciences Montpellier, Maison des Sciences de l'Eau place Bataillon, Montpellier, 34095, France
AB: We present a new project using multi-disciplinary data (gravity, geodesy, hydrology, and meteorology) to determine seasonal changes in water storage in Africa. We foresee to concentrate on two areas: the desert zone in the Sahara (Tamanrasset, Algeria) where almost no hydrological change is present, and the equatorial monsoon band (Niger, Benin Republic) that provides on the contrary a large rainfall signal. This project will be a first attempt to do a ground validation of satellite-derived gravity observations such as GRACE or GOCE in Africa. We will pay attention to the various length scales involved in hydrological processes that are differently retrieved whether gravity is measured at the ground or by satellite. Our experience includes two types of ground-based gravity measurements. First we will perform a repeated survey with absolute gravimeters (AG) on a North-South profile during 2-3 years (2008-2010) to assess the large soil moisture changes as predicted by existing hydrological models such as GLDAS or LadWorld. Second we plan to establish a superconducting gravimeter (SG) to act as a continuously monitored base station in a region of large soil moisture changes. In addition, continuous geodetic GPS measurements will be made along the gravity profile to assess the vertical deformation which acts to alter ground gravity but not satellite gravity. In-situ measurements of hydrological parameters at each station will assist us in modelling local gravity effects. The goal is a better characterization of continental water storage, particularly in the critical areas of water management in the north and central parts of the African continent.
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 1848 Monitoring networks
DE: 1876 Water budgets
SC: Hydrology [H]
MN: 2007 Fall Meeting