Regional Analysis of Convective Storms

Abstract

With the support of a dense hydrometeorological telemetric network of 24 stations over an area of 625 km² surrounding the metropolitan area of Mendoza city (central west Argentina) at 33° S, a detailed study of thunderstorm rainfall fields was carried out to obtain standard project storms for the area. In the region, precipitation-frequency relations for small arid basins that produce flash floods are difficult to estimate, basically due to the extreme temporal and spatial variability of precipitation. The high density and synchronized rain gauge network permits the detailed determination of rainfall fields in space and time for an arid zone of the southern hemisphere, where the lack of good-quality and highly resoluted rainfall data has been a major hindrance for operation, design, and research. To have a composite record for the area using the concept of station-storm, a regional analysis of convective storms was done on a sample of 140 events. First, precipitation zones were defined according to stations-elevations and then a grouping of stations was obtained by means of a statistical determination with the multivariate method of principal component analysis. Second, relations between the two lower zones were done using a comparison of the average slope of short-duration rainfall intensity curves between 10 and 5 years of time of return for durations of up to 30 and 60 min. The final aim of the study was to provide a procedure for the regional analysis of convective storms and produce practical tables for the standard project storm for the area.