The Standardized Precipitation Index (SPI) and the Palmer Drought Severity Index, on it’s original form (PDSI) and on it’s climate conditions of the State of São Paulo adapted model (PDSI adap) are been used by the Instituto Agronômico (IAC) through the CIIAGRO to evaluate the agricultural, the meteorological, the hydrological and the socioeconomic impacts of a drought. Regarding the particular characteristics of each index, this study compares the SPI, the PDSI and the PDSI adap models. This work also gives information about the correct interpretations of the results for each drought index. Due it’s capability to recognizes the importance of time scales in the analysis of water availability and water use, due it’s spatial consistence and it’s simplicity interpretation the SPI should be used on studies of drought risk and mitigation over different segments of the human society. The PDSI adap could be used as a "meteorological drought monitoring tool", in monthly basis, on the State of São Paulo.
precipitation deficit; drought risk; mitigation
