Analysis of the occurrence of wet and drought periods using standardized precipitation index in mato grosso do sul state, brazil

Abstract

In order to generate information relevant to the Mato Grosso do Sul (MS), the aim was analyze the occurrence of wet and drought periods through the SPI using Standardized Precipitation Index (SPI) in this Brazilian State. Rainfall data of 29 stations (sites) of MS were obtained of the National Water Agency Database collected from 1983-2013. At each site and year, the rainfall daily data were added up to obtain the monthly rainfall (mm monthG 1), of each month of the year. Thus, were formed 348 time series (12 months×29 sites), that it were used to calculate the SPI in annual scale. The fit was found Normal distribution of 384 time series of monthly rainfall using the Kolmogorov-Smirnov test. The SPI is able to identify the drought and wet periods, when the occurrence of ENOS events, regardless of categorization, in Mato Grosso do Sul State, Brazil. The analysis of the relative frequencies shows that the moderately drought and wet categories stands out about the other categories of SPI. The moderately drought category occurs in episodes of El Niño strong and moderate and moderately wet category in episodes of La Niña strong and weak.