THE DISTRIBUTION OF SUMMER SHOWERS OVER A SMALL AREA

Abstract

The scatter of summer showers in both time and space over the southeastern States is such that the distribution of synoptic weather reporting does not permit an accurate appraisal of the distribution of rainfall. The objectives of this investigation are to determine (1) the density of the reporting network that would be necessary to describe the areal coverage of rainfall in a given locality, and (2) the relation between this areal coverage and the average amount of rain. The localities chosen for study are Birmingham, Ala. and Atlanta, Ga., and the areas representative of these localities are defined as circles of about 50-mile radius around the Birmingham and Atlanta airports. Precipitation data used to determine the areal distribution were taken from 37 cooperative stations plus 3 first-order reporting stations in each of these areas. An analysis of these data shows, for most purposes at least, that this distribution of 40 stations provides a good indication of the precipitation coverage, and further, that an observation from one station or even the 3 first-order stations is not representative of the areal coverage. A close relationship is found between the average amount of rain per station and the areal coverage.