Document atmospheric forcing and reference evapotranspiration (Eto) estimation. This dataset is part of the AMMA-CATCH eco-hydrological observatory over West Africa Measurements of meteorological variables. The sensors are attached to a 2m hight mast, the wind is measured at 2 m. Measurements are made at 10 s intervals, data are averaged and recorded every 15 min in the data logger. Lebel, T., Cappelaere, B., Galle, S., Hanan, N., Kergoat, L., Levis, S., Vieux, B., Descroix, L., Gosset, M., Mougin, E., Peugeot, C., Seguis, L., 2009: AMMA-CATCH studies in the Sahelian region of West-Africa: An overview. Journal of Hydrology, 3-13, doi:10.1016/j.jhydrol.2009.03.020. Galle S., Roko F., Le Lay M., Peugeot C., 2007: Variability of reference evapotranspiration over the upper Ouémé basin (Benin) for 40 years. In: J.-L. Redelsberger (Editor), "2nd AMMA Int. Conf." AMMA, Karlsruhe GE.