Drought characteristics for the south region of Brazil from 1983 to 2012: meteorological and hydrological approaches

Abstract

An effective way to classify and evaluate droughts is the adjustment of hydrological series into drought indices. With this purpose, two different drought indices were applied to series of the South Region of Brazil, a location with the majority of hydrological studies not focused in low extremes. The Standardized Precipitation Index (SPI) and the Streamflow Drought Index (SDI) were applied for meteorological and hydrological analysis. The main focus of the study was to identify trends in these indices, and to analyze possible spatial patterns over the study area. From the results, it was verified the increase in drought severity in southern part of the study area, while decreasing trends were observed in eastern and northwestern parts. In the hydrological seasonal analysis, results have evidenced that in months with usually lower flows than the yearly average the rates are becoming even lower, while in months with higher flows the rates are increasing.