O. Andersen, J. Hinderer, and F. Lemoine, Seasonal gravity field variations from GRACE and hydrological models, Gravity, Geoid and Space Missions. IAG Symposia, vol.129, pp.316-321, 2005.

B. C. Bates, Z. W. Kundzewicz, S. Wu, and . Palutikof, Climate Change and Water. Tech. Paper of the Intergovernmental Panel on Climate Change, IPCC Secretariat, p.210, 2008.

M. Bevis, D. Alsdorf, E. Kendrick, L. Fortes, B. Forsberg et al., Seasonal fluctuations in the mass of the Amazon river system and Earth's elastic response, Geophys. Res. Lett, vol.32, p.16308, 2005.

O. Bock, M. N. Bouin, E. Doerflinger, P. Collard, F. Masson et al., The West African Monsoon observed with ground-based GPS receivers during AMMA, J. Geophys. Res, vol.113, p.21105, 2008.

J. Boy and J. Hinderer, Study of the seasonal gravity signal in superconducting gravimeter data, J. Geodyn, vol.41, pp.253-258, 2006.

M. T. Coe and J. A. Foley, Human and natural impacts on the water ressources of the Lake Chad basin, J. Geophys. Res. (Atmos.), vol.106, issue.D4, pp.3349-3356, 2001.

M. T. Coe and C. M. Birkett, Calculation of river discharge and prediction of lake height from satellite radar altimetry: example for the Lake Chad basin, Water Resour. Res, vol.40, p.10205, 2004.

D. Crossley, J. Hinderer, G. Casula, O. Francis, H. Hsu et al., Network of superconducting gravimeters benefits a number of disciplines, Transactions, vol.80, issue.11, pp.125-126, 1999.

D. Crossley and J. Hinderer, GGP ground truth for satellite gravity missions, Bull. Inf. Marées Terr, vol.136, pp.10735-10742, 2002.

D. Crossley, J. Hinderer, M. Llubes, and N. Florsch, The potential of ground gravity measurements to validate GRACE data, Adv. Geosci, vol.1, pp.1-7, 2003.
URL : https://hal.archives-ouvertes.fr/hal-00328591

D. Crossley, J. Hinderer, and J. Boy, Regional gravity variations in Europe from superconducting gravimeters, J. Geodyn, vol.38, pp.325-342, 2004.

D. Crossley, J. Hinderer, and J. Boy, Time variation of the European gravity field from superconducting gravimeters, Geophys. J. Int, vol.161, pp.257-264, 2005.

J. Davis, P. Elosegui, J. Mitrovica, and M. Tamisea, Climate-driven deformation of the solid Earth from GRACE and GPS, Geophys. Res. Lett, vol.31, p.24605, 2004.

M. Descloitres, L. Séguis, M. Wubda, and A. Legchenko, Discrimination of rocks with different hydrodynamic properties using MRS, EM and resistivity methods. Paper B33, 13th European Meeting on Environmental and Engineering Geophysics "Near Surface, 2005.

M. Descloitres, L. Ruiz, M. Sekhar, A. Legchenko, J. J. Braun et al., Characterization of seasonal local recharge using Electrical Resistivity Tomography and Magnetic Resonance Sounding, Hydrol. Process, vol.22, pp.384-394, 2008.
URL : https://hal.archives-ouvertes.fr/insu-00388660

C. De-linage, J. Hinderer, and J. Boy, A search on the gravity/height ratio induced by surface loading; theoretical investigation and numerical applications, Bull. Inf. Marées Terr, vol.143, pp.11451-11460, 2006.

C. De-linage, J. Hinderer, and Y. Rogister, A search for the ratio between gravity variation and vertical displacement due to a surface load, Geophys. J.Int, vol.171, pp.986-994, 2007.

G. Favreau, B. Cappelaere, S. Massuel, M. Leblanc, M. Boucher et al., Land clearing, climate variability, and water resources increase in semiarid southwest Niger: a review, Water Resour. Res, vol.45, pp.0-16, 2009.

G. Gaultier, Recharge et paléorecharge d'une nappe libre en milieu Sahélien (Niger oriental): approche géochimique et hydrodynamique, 2004.

C. L. Gehman, D. L. Harry, W. E. Sanford, J. D. Stednick, and N. A. Beckman, Estimating specific yield and storage change in an unconfined aquifer using temporal gravity surveys, Water Resour. Res, vol.45, pp.0-21, 2009.

S. Han, C. K. Shum, C. Jekeli, and D. Alsdorf, Improved estimation of terrestrial water storage changes from GRACE, Geophys. Res. Lett, vol.32, p.7302, 2005.

J. Hinderer and D. Crossley, Time variations in gravity and inferences on the Earth's structure and dynamics, Surv. Geophys, vol.21, pp.1-45, 2000.

J. Hinderer and D. Crossley, Scientific achievements from the first phase (1997-2003) of the Global Geodynamics Project using a worldwide network of superconducting gravimeters, J. Geodyn, vol.38, pp.237-262, 2004.

J. Hinderer, C. De-linage, and J. Boy, How to validate satellite-derived gravity observations with gravimeters at the ground?, Bull. Inf. Marées Terr, vol.142, pp.11433-11441, 2006.

J. Hinderer, O. Andersen, F. Lemoine, D. Crossley, and J. Boy, Seasonal changes of the Earth's gravity field from GRACE: a comparison with ground measurements from superconducting gravimeters and with hydrology model predictions, J. Geodyn, vol.41, pp.59-68, 2006.

T. Jacob, R. Bayer, J. Chery, H. Jourde, N. Le-moigne et al., Absolute gravity monitoring of water storage variation in a, 2008.
URL : https://hal.archives-ouvertes.fr/hal-00411884

, J. Hydrol, vol.359, issue.1-2, pp.105-117

B. Kamagaté, L. Séguis, G. Favreau, J. L. Seidel, M. Descloitres et al., Hydrological processes and water balance of a tropical crystalline bedrock catchment in Benin, C.R. Geosci, vol.339, pp.418-429, 2007.

T. Lebel, J. Redelsperger, and C. Thorncroft, African Monsoon Multidisciplinary analysis (AMMA) project, Gewex Newsl, vol.13, issue.4, pp.8-9, 2003.
URL : https://hal.archives-ouvertes.fr/ird-02153235

T. Lebel, A. Diedhiou, and H. Laurent, Seasonal cycle and interannual variability of the Sahelian rainfall at hydrological scales, J. Geophys. Res, vol.108, issue.D8, p.8389, 2003.

M. Leblanc, G. Favreau, S. Tweed, C. Leduc, M. Razack et al., Remote sensing for groundwater modelling in large semiarid areas: Lake Chad Basin, Africa. Hydrogeol. J, vol.15, pp.97-100, 2007.
URL : https://hal.archives-ouvertes.fr/ird-00164820

C. Leduc, S. Sabljak, J. D. Taupin, C. Marlin, and G. Favreau, Recharge of the Quaternary water table in the northwestern Lake Chad basin (southeastern Niger) estimated from isotopes, C.R. Acad. Sci. Paris IIa, vol.330, issue.5, pp.355-361, 2000.

C. Leduc, G. Favreau, and P. Schroeter, Long-term rise in a Sahelian water-table: the Continental Terminal in South-West Niger, J. Hydrol, vol.243, pp.43-54, 2001.

L. Lay, M. Galle, and S. , How changing rainfall regimes may affect the water balance. A modelling approach in West Africa in «Regional hydrological impacts of climatic changes-Hydroclimatic variability, pp.203-210, 2005.

L. Lay, M. Saulnier, G. Galle, S. Séguis, L. Métadier et al., Model representation of the Sudanian hydrological processes. Application on the Donga catchment (Benin), J. Hydrol, 2008.
URL : https://hal.archives-ouvertes.fr/halsde-00400174

J. Lemoalle, J. C. Nihoul, and P. O. Zavialov, Dying and Dead Seas: Climatic versus Anthropic Causes, Proceedings of the NATO Advanced Workshop on Dying and Dead Seas, vol.36, pp.321-329, 2003.

J. Lemoine, S. Bruinsma, S. Loyer, R. Biancale, J. Marty et al., Temporal gravity field models inferred from GRACE data, Adv. Space Res, vol.39, pp.1620-1629, 2007.

. L'hote and . Mahé, Afrique centrale et de l'Ouest: carte des precipitation moyennes annuelles (période 1951-1989)-IRD (ORSTOM), 1996.

S. Massuel, G. Favreau, M. Descloitres, Y. Le-troquer, Y. Albouy et al., Deep infiltration through a sandy alluvial fan in semiarid Niger inferred from electrical conductivity survey, vadose zone chemistry and hydrological modelling, CATENA, vol.67, issue.2, pp.105-118, 2006.
URL : https://hal.archives-ouvertes.fr/ird-00165668

P. C. Milly and A. B. Shmakin, Global modeling of land water and energy balances. Part I: The land dynamics (LaD) model, J. Hydrometeorol, vol.3, issue.3, pp.283-299, 2002.

M. Naujoks, A. Weise, C. Kroner, and T. Jahr, Detection of small hydrological variations in gravity by repeated observations with relative gravimeters, J. Geodesy, vol.82, pp.543-553, 2008.

J. Neumeyer, F. Barthelmes, O. Dierks, F. Flechtner, M. Harnisch et al., Combination of temporal gravity variations resulting from Superconducting Gravimeter (SG) recordings, GRACE satellite observations and global hydrology models, J. Geodesy, 2006.

T. Niebauer, G. Sasagawa, J. Faller, R. Hilt, and F. Klopping, A new generation of absolute gravimeters, Metrologia, vol.32, pp.159-180, 1995.

D. R. Pool and J. H. Eychaner, Measurements of aquifer-storage change and specific yield using gravity surveys, Ground Water, vol.33, issue.3, pp.425-432, 1995.

G. Ramillien, A. Cazenave, and O. Brunau, Global time variations of hydrological signals from GRACE satellite gravimetry, Geophys. J. Int, vol.158, pp.813-826, 2004.
URL : https://hal.archives-ouvertes.fr/hal-00280243

J. L. Redelsperger, C. D. Thorncroft, A. Diedhiou, T. Lebel, D. J. Parker et al., African Monsoon Multidisciplinary Analysis: an international research project and field campaign, Bull. Am. Meteorol. Soc, vol.87, pp.1739-1746, 2006.
URL : https://hal.archives-ouvertes.fr/insu-00385875

M. Rodell, P. R. Houser, U. Jambor, J. Gottschalck, K. Mitchell et al., The Global Land Data Assimilation System, Bull. Am. Meteor. Soc, vol.85, issue.3, pp.381-394, 2004.

R. Schmidt, P. Schwintzer, F. Flechtner, C. Reigber, A. Güntner et al., GRACE observations of changes in continental water storage. Global Planet, Changes, vol.50, pp.112-126, 2006.
URL : https://hal.archives-ouvertes.fr/hal-00280253

L. Séguis, B. Cappelaere, G. Milési, C. Peugeot, S. Massuel et al., Simulated impacts of climate change and land-clearing on runoff from a small Sahelian catchment, Hydrol. Process, vol.18, pp.3401-3413, 2004.

T. Syed, J. Famiglietti, J. Chen, M. Rodell, S. Seneviratne et al., Total basin discharge for the Amazon and Mississippi river basins from GRACE and a land-atmosphere water balance, Geophys. Res. Lett, vol.32, p.24404, 2005.

B. Tapley, S. Bettadpur, J. Ries, P. Thompson, and M. Watkins, Grace measurements of mass variability in the Earth system, Science, vol.305, pp.503-505, 2004.

M. Van-camp, M. Vanclooster, O. Crommen, T. Petermans, K. Verbeeck et al., Hydrogeological investigations at the Membach station, Belgium and application to correct long periodic gravity variations, J. Geophys. Res, vol.111, p.10403, 2006.

N. Varado, I. Braud, S. Galle, M. Le-lay, L. Séguis et al., Multi-criteria assessment of the Representative Elementary Watershed approach on the Donga catchment (Benin) using a downward approach of model complexity, Hydrol. Earth Syst. Sci, vol.10, pp.427-442, 2006.
URL : https://hal.archives-ouvertes.fr/hal-00330791

J. M. Vouillamoz, M. Descloitres, G. Toe, and A. Legchenko, Characterization of crystalline basement aquifers with MRS: comparison with boreholes and pumping tests data in Burkina, Near Surf. Geophys, vol.3, pp.107-111, 2005.
URL : https://hal.archives-ouvertes.fr/insu-00385396

J. M. Vouillamoz, G. Favreau, S. Massuel, M. Boucher, Y. Nazoumou et al., Contribution of magnetic resonance sounding to aquifer characterization and recharge estimate in semiarid Niger, J. Appl. Geophys, vol.64, pp.99-108, 2008.
URL : https://hal.archives-ouvertes.fr/insu-00389204

J. Wahr, S. Swenson, V. Zlotnicki, and I. Velicogna, Time-variable gravity from GRACE: first results, Geophys. Res. Lett, vol.31, issue.11, p.11501, 2004.

J. Wahr, S. Swenson, and I. Velicogna, Accuracy of GRACE mass estimates, Geophys. Res. Lett, vol.33, p.6401, 2006.

P. J. Yeh, .. Swenson, S. C. Famiglietti, J. S. Rodell, and M. , Remote sensing of groundwater storage changes in Illinois using the Gravity Recovery and Climate Experiment (GRACE), Water Resour. Res, vol.42, p.12203, 2006.