POTENTIAL INSOLATION AS A TOPOCLIMATIC CHARACTERISTIC OF DRAINAGE BASINS

Abstract A method is derived for characterizing drainage basins and other land areas in terms of their “average” exposure and potential irradiation by the sun. The most efficient trigonometric and graphical procedures for evaluating potential insolation upon sloping surfaces are selected, and the concept of a “theoretical intercepting surface” is employed to describe terrain elements in terms of a single-valued facet. Applications with secondary experimental data indicate that there is a strong positive correlation between derived “radiation indexes”, and evapotranspiration as measured by the precipitation-runoff difference.