Avaliação adaptação do Índice de Severidade de Seca de Palmer (PDSI) e do Índice Padronizado de Precipitação (SPI) às condições climáticas do Estado de São Paulo

Abstract

A drought event for the Palmer Drought Severity Index (PDSI) is defined as a period of time during which the actual moisture supply at a given place rather consistently falls short of the climate appropriate moisture supply. Based on historical precipitations series, which were fitted to the gamma distribution, the Standardized Precipitation Index (SPI) recognizes the importance of the time scale in the analysis of the water availability and water management. Based on parameters of the water balance of thirteen regions, the scope of this study was to test and adapt the PDSI and the SPI models to the climate conditions of the State of São Paulo. The tests were done caring out the index values and the deviations between the estimated water balance parameters in a period and the climate expected value of this parameters for the period that is been considerate. The SPI values were tested in several times scales. The main focus of the PDSI adjustment (PDSl adap) was the adaptation of the K factor and the Palmer's index final equation. The analysis allows to conclude that such study resulted in a useful tool for the monthly "real time monitoring" of the meteorological drought conditions for the State of São Paulo. The SPI model also demonstrated to be a consistent "precipitation deficit monitoring tool" in several time scales. Both indices should be used as part of a overall state government actions to drought affected regions and mitigation policy.