This research was funded by the NERC through its TIGER (Terrestrial Initiatives in Global Environmental Research) programme, Award GST/91/III.2/2A. Funding of the EPSAT–Niger experiment by the TOA department of ORSTOM and from INSU (Institut National des Sciences de l’Univers) is gratefully acknowledged. The authors would also like to thank Chris Huntingford, Richard Harding, and the reviewers for their comments on the manuscript.
Anthes, R. A., 1984: Enhancement of convective precipitation by mesoscale variations in vegetative covering in semi-arid regions. J. Climate Appl. Meteor.,23, 541–554.
Barnston, A. G. and P. T. Schickedanz, 1984: The effect of irrigation on warm season precipitation in the Southern Great Plains. J. Climate Appl. Meteor.,23, 865–888.
Beljaars, A. C. M., P. Viterbo, M. J. Miller, and A. K. Betts, 1996:The anomalous rainfall over the United States during July 1993—Sensitivity to land-surface parameterization and soil moisture. Mon. Wea. Rev.,124, 362–383.
Brubaker, K. L. and D. Entekhabi, 1996: Asymmetric recovery from wet versus dry soil moisture anomalies. J. Appl. Meteor.,35, 94–109.
——, ——, and P. S. Eagleson, 1993: Estimation of continental precipitation recycling. J. Climate,6, 1077–1089.
Chang, J. T. and P. J. Wetzel, 1991: Effects of spatial variations of soil moisture and vegetation on the evolution of a prestorm environment—A numerical case study. Mon. Wea. Rev.,119, 1368–1390.
Charney, J. G., 1975: Dynamics of deserts and drought in the Sahel. Quart. J. Roy. Meteor. Soc.,101, 193–202.
Chen, F. and R. Avissar, 1994: Impact of land-surface moisture variability on local shallow convective cumulus and precipitation in large-scale models. J. Appl. Meteor.,33, 1382–1401.
Dirmeyer, P. A. and J. Shukla, 1996: The effect on regional and global climate of expansion of the worlds deserts. Quart. J. Roy. Meteor. Soc.,122, 451–482.
Ek, M. and L. Mahrt, 1994: Daytime evolution of relative humidity at the boundary layer top. Mon. Wea. Rev.,122, 2709–2721.
Findell, K. L. and E. A. B. Eltahir, 1997: An analysis of the soil moisture–rainfall feedback, based on direct observations from Illinois. Water Resour. Res.,33, 725–735.
Gash, J. H. C., and Coauthors, 1997: The variability of evaporation during the HAPEX-Sahel intensive observation period. J. Hydrol.,189, 385–399.
Goutorbe, J. P., and Coauthors, 1994: HAPEX-Sahel—A large-scale study of land-atmosphere interactions in the semi-arid tropics. Ann. Geophys.,12, 53–64.
Houze, R. A., 1977: Structure and dynamics of a tropical squall-line system. Mon. Wea. Rev.,105, 1540–1567.
Lanicci, J. M., T. N. Carlson, and T. T. Warner, 1987: Sensitivity of the Great Plains severe-storm environment to soil moisture distribution. Mon. Wea. Rev.,115, 2660–2673.
Lare, A. R. and S. E. Nicholson, 1994: Contrasting conditions of surface water balance in wet years and dry years as a possible land surface–atmosphere feedback mechanism in the West African Sahel. J. Climate,7, 653–668.
Lebel, T., J. D. Taupin, and N. D’Amato, 1997: Rainfall monitoring during HAPEX-Sahel: 1. General rainfall conditions and climatology. J. Hydrol.,189, 74–96.
——, H. Sauvageot, M. Hoepffner, M. Desbois, B. Guillot, and P. Hubert, 1992: Rainfall estimation in the Sahel: The EPSAT-Niger experiment. Hydrol. Sci. J.,37, 201–215.
Oglesby, R. J. and D. J. Erickson, 1989: Soil moisture and the persistence of North American drought. J. Climate,2, 1362–1380.
Raupach, M. R. and J. J. Finnigan, 1995: Scale issues in boundary-layer meteorology: surface energy balances in heterogeneous terrain. Hydrol. Processes,9, 589–612.
Rowell, D. P. and C. Blondin, 1990: The influence of soil wetness distribution on short-range rainfall forecasting in the West African Sahel. Quart. J. Roy. Meteor. Soc.,116, 1471–1485.
Sun, W. Y. and Y. Ogura, 1979: Boundary-layer forcing as a possible trigger to a squall-line formation. J. Atmos. Sci.,36, 235–254.
Taylor, C. M., F. Saïd, and T. Lebel, 1997: Interactions between the land surface and mesoscale rainfall variability during HAPEX-Sahel. Mon. Wea. Rev.,125, 2211–2227.
Walker, J. and P. R. Rowntree, 1977: The effect of soft moisture on circulation and rainfall in a tropical model. Quart. J. Roy. Meteor. Soc.,103, 29–46.
Wallace, J. S. and C. J. Holwill, 1997: Soil evaporation from tiger bush in south west Niger. J. Hydrol.,189, 426–442.