Fitting a third-order markov rainfall model to interpolated climatic surfaces

A procedure to link a third-order Markov rainfall model to interpolated monthly mean climate surfaces is described. Such preliminary surfaces have been constructed for Africa and Latin America and these allow a user to generate daily weather data (rainfall, temperatures and solar radiation) that can be used for purposes of system characterisation and to drive a wide variety of crop and livestock production and ecosystem models. For applications with a time resolution of a few weeks or a growing season the surfaces described already have substantial utility. Indicators of reliability both spatially, in map form, and as summaries of goodness of fit for the model parameters are presented. The surfaces were tested for goodness of fit for three contrasting sites in the tropics and refinements to improve the interpolation methodology identified.