Hinderer J. auteur aut IRD Pfeffer Julia auteur aut IRD Boucher Marie auteur aut IRD Nahmani S. auteur aut IRD De Linage C. auteur aut IRD Boy J. P. auteur aut IRD Genthon Pierre auteur aut IRD Séguis Luc auteur aut IRD Favreau Guillaume auteur aut IRD Bock O. auteur aut IRD Descloitres Marc auteur aut IRD text journalArticle eng text/pdf born digital access This paper is devoted to the first results from the GHYRAF (Gravity and Hydrology in Africa) experiment conducted since 2008 in West Africa and is aimed at investigating the changes in water storage in different regions sampling a strong rainfall gradient from the Sahara to the monsoon zone. The analysis of GPS vertical displacement in Niamey (Niger) and Djougou (Benin) shows that there is a clear annual signature of the hydrological load in agreement with global hydrology models like GLDAS. The comparison of GRACE solutions in West Africa, and more specifically in the Niger and Lake Chad basins, reveals a good agreement for the large scale annual water storage changes between global hydrology models and space gravity observations. Ground gravity observations done with an FG5 absolute gravimeter also show signals which can be well related to measured changes in soil and ground water. We present the first results for two sites in the Sahelian band (Wankama and Diffa in Niger) and one (Djougou in Benin) in the Sudanian monsoon region related to the recharge-discharge processes due to the monsoonal event in summer 2008 and the following dry season. It is confirmed that ground gravimetry is a useful tool to constrain local water storage changes when associated to hydrological and subsurface geophysical in situ measurements. specialized African monsoon Sahel water storage gravimetry GPS MRS GRACE 062 169 8 1391-1410 2012 0033-4553 https://www.documentation.ird.fr/hor/fdi:010057107 10.1007/s00024-011-0417-9 0033-4553 [F B010057107] https://www.documentation.ird.fr/hor/fdi:010057107 https://www.documentation.ird.fr/intranet/publi/2012/09/010057107.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2012-10-03 2023-02-06 fdi:010057107 fre