Trend analysis of rain indicators for the state of Bahia, Brazil

Abstract

The concern about the climate issue has been increasing since climate change influence the water resources system. For this reason, this study sought to identify the presence of trends in the historic series of two meteorological variables: total annual precipitation and number of rain days, in the state of Bahia, Brazil, in order to verify if the precipitation regime is being affected by the global climate change. Two trend tests were applied: Mann-Kendall and Linear Regression, with significance levels of 5% and 10%, in the historical series of 32pluviometric stations distributed throughout the state. The results of the two testes were similar, which guarantees that both can be used for detection of changes in rain pattern. The study confirms that in a specific region of Bahia, more specifically in the central and eastern areas, there is a reduction trend in the historical series of annual precipitation. Regarding the number of rain days, no trend conclusions were observed.