A Revised Version of Lettau's Evapoclimatonomy Model

Abstract

In this paper a revised version of Lettau's evapoclimatonomy model is introduced. Climatonomy is a one-dimensional representation of mean climate, which includes a complete characterization of the surface energy and water balances. The model is fundamentally forced by two input variables: incoming solar radiation and precipitation. All processes related to the ultimate distribution and exchange of the thereby available energy and moisture are parameterized. The goal of this paper is to describe the model's evolution and demonstrate its utility by sketching results of its application to several diverse climate problems in arid and semiarid Africa. Both the original and the revised evapoclimatonomy models are described, their conceptualization to that of more recent land-atmosphere interaction schemes is compared, their components in terms of the ecosystem are interpreted, and the model improvements incorporated in the current version are proposed. Finally, the use of the model in three applications to studies of climate and ecology in the Sahel and Kalahari regions of Africa is illustrated.