Climate controls on the terrestrial water balance: Influence of aridity on the basin characteristics parameter in the Budyko framework.

The terrestrial water balance can be represented by the ratio of evapotranspiration to precipitation, which is expressed as a function of the aridity index (ϕ) and the basin characteristics parameter (n) in the Budyko framework. Traditionally n is assumed to be a constant for a catchment, independent to the climatic variables and altered only by changes in land cover and human activities. Another conceptual framework, Climate Change Impact Hypotheses (CCUW), makes similar assumption of constant catchment efficiency for evapotranspiration.