Análise de seca no estado da Paraíba utilizando dados do satélite TRMM 3B42 V7

Abstract

Drought monitoring is an extremely important tool to the making decision process regarding the use of water resources, especially in the arid and semiarid regions of the planet. However, the scarcity of consistent data that well characterize the rainfall spatial-temporal distribution is a problem faced by several researchers. In this sense, the present work aims to analyze the spatial-temporal behavior of short-, medium- and long-term droughts in the state of Paraíba, northeastern Brazil, based on the SPI index, for the period 1998–2015, using data from the TRMM satellite. The TRMM data were validated by comparing to data from 267 rain gauges and the consistency of the satellite data was demonstrated both for total monthly rainfall levels and for the determination of the number of dry and wet days. Thus, 187 time series of daily TRMM precipitation were used, each one with 6574 daily records, equally distributed over the entire study area, which confirmed that the first semester is rainy season and the second one is the driest period of the region. The Paraiba coast had the highest rainfall levels, whereas the regions of Agreste and Borborema had the lowest rainfall levels. In addition, there was a high occurrence of dry days over the whole region, mainly in the months of September, October and November. In order to analyze the droughts, eight SPI indices were used to characterize the short-, medium- and long-term droughts and by the cluster analysis, the results revealed that all regions of Paraíba state had basically the same behavior when analyzing the short-, mediumand long-term droughts over the studied 18 years. In addition, it was noticed that since 2012, the entire state of Paraíba as a whole, was significantly affected by droughts, as in 2015, there were dry events in basically the entire region when analyzing the short-, medium- and longterm droughts. Finally, the results show that the Borborema region presents the most critical situation in the state of Paraíba, since it was significantly affected by the short-, medium- and long-term droughts when analyzing the extreme and severe drought events. Sertão, in turn, was also affected by short-, medium- and long-term droughts, when analyzing the extremely dry events. The coastal and the Agreste, in contrast, were considerably affected by short-, mediumand long-term droughts, when analyzing the moderate and mild drought events. In general, it was observed that when analyzing the long-term droughts, the occurrence of extreme drought events was greater than when analyzing the short- and medium-term droughts