Trends of rainfall and temperature in Northeast Brazil

For climate change scenarios, there is a high degree of complexity, with impacts on the future availability of water resources. In this context, studies related to changes in rainfall time series are essential in order to identify environmental vulnerability. The objective of this study was to analyze trends in the rainfall regime, number of rainy days and temperature for stations located at different continentality and altitude conditions in Northeast Brazil. Meteorological data of the Instituto Nacional de Meteorologia were used, being classified according to the location in relation to the continent: coastal strip (14 stations), strip of 150-300 km up to 300 m altitude (14 stations) and above 300 m (five stations), between 400 and 600 km from the coast up to 300 m (four stations) and above 300 m (eight stations). All the 45 stations used have a historical series with a data period of more than 30 years. The trend of rainfall and rainy days was obtained through the Mann-Kendall and regression analyses, at significance levels of 0.01 and 0.05, respectively. There were trends of reduction in the number of rainy days, in the coastal strip, as well as reduction in rainfall and rainy days, both in the strip of 150-300 km from the coast and in the Sertao region, with no significant effect of continentality in the strip of 400-600 km from the coast. For temperature, except for Maceio, AL, Brazil, there is a trend of increase in near future.