Variabilidade espacial e temporal de precipitação pluviométrica na bacia hidrográfica do rio mogi guaçu

Abstract

The aim of this study was to analyze the annual and seasonal rainfall variability, both in its size and spatial distribution to determine rainfall homogeneous regions in the mogi guaçu river basin We used monthly rainfall data from 40 pluviometric stations over the period 1975-1999. In the first stage of this work, we analyzed rainfall data by using descriptive statistics, observing that several years had different rainfall characteristics. It was considered (in this analysis), the annual rainfall maps for each year of the period, and a chromatic spreadsheet classification of standard years. It was attributed colors to the maps and spreadsheet, which followed a scale defined by Sturges' rule. From the classified years, it was picked up 1983 (rainy pattern), 1994 (dry standard) and 1995 (the usual standard), to identify possible oscillations in the seasonal rainfall. Later, it had been done cluster analysis, using the hierarchical agglomerative method, using Ward's coefficient to identify homogeneous groups of climatic stations, generating four homogenous groups. These groups have identified homogeneous regions in the basin as a function of annual precipitation. In this analysis, it was possible to find groups with the same behavior, that is, regions with the highest and lowest rainfall indexes.