Rainstorm Analysis and Rainfall Erosivity of a Seasonal Tropical Region with a Strong Cyclonic Influence on the Pacific Coast of Mexico

Abstract

The objective of this paper is to analyse the rainstorm pattern and rainfall erosivity of a seasonal tropical region in Mexico. Depth, duration, and intensity values of precipitation were obtained for all individual storms from continuous chart records during the period of 1983?90 near Chamela on the Pacific coast of Mexico. The rainstorm pattern was analyzed by fitting the total series to a gamma probability distribution. Intensity?duration and intensity?depth relationships were fit with an inverse polynomial model. The rainfall pattern of Chamela has two types of storms: convective and tropical cyclone. The first has low depth and high-occurrence frequency. As a consequence, distribution data of depth, duration, and intensity were skewed to the lower values. However, cyclonic storms strongly influenced rainfall pattern, annual precipitation, and runoff production. Rainfall intensity correlated significantly with depth by cyclone influence. The mean annual erosivity was 6525.2 MJ mm ha?1 h?1, and the most erosive storms are mainly tropical cyclones.