On the feasibility of using a lake water balance model to infer rainfall: an example from Lake Victoria

A water balance model of Lake Victoria that can be used to assess rainfall from lake level, is derived. The model utilizes satellite estimates of rain fall directly over the lake. The model, initially derived and calibrated fo r the period 1956-1978, is reformulated here in such a way that all water b alance terms except evaporation can be calculated from a combination of cat chment rainfall and level of the lake. The reformulated model is validated and used to predict lake level fluctuations during the period 1931-1994. An error analysis is also performed. The model is then "inverted" to solve fo r mean rainfall conditions during various intervals of changing lake levels . For modern periods with known rainfall conditions, the error in model est imates is of the order of 1%.