Abstract
This study discusses the role of the aridity index in controlling the
long-term fluxes of direct (Qd) and baseflow (Qd). Here we present an
analytical derivation starting from similar assumptions as the one
presented in the original work of Budyko that leads to two simple
expressions for the control of the aridity index on Qb and Qd. These two
analytical equations can be combined into a single expression with the
same properties as the original Budyko equation. Our study provides a
method for predicting long term baseflow and direct runoff for poorly
gaged basins as well as permit the derivation of sensitivity equations
for the assessment of the impact of these fluxes with respect to changes
in aridity index.