Índices climáticos extremos de precipitação pluvial e temperatura do ar na região do MATOPIBA-Brasil

Abstract

Temperature and precipitation parameters are important for obtaining information related to climate change and extreme events that affect our lives. This study aims to analyze annual trends of indices of climatic extremes of air temperature and rainfall obtained using the RClimdex software, for the MATOPIBA region (it includes mainly Cerrado areas of the states of Maranhão, Tocantins, Piauí and Bahia), as well as to group the microregions in homogeneous regions by means of the Ward’s method in hierarchical clustering (1963), employing values of the Simple precipitation intensity index - SDII. Data from daily historical series (1950-2004) of maximum and minimum air temperatures and rainfall acquired from the Water Weather Energy Ecosystembase (https://www.2w2e.com/home/CIMP) were used. The trends obtained for the microregions and homogeneous regions were evaluated for the level of significance, and those with a p-value < 0.05 were considered statistically significant. Considering trends by microregion, most precipitation indices demonstrate reduction in extreme incidences. Only for the indices Rx5day, CDD and CWD were obtained significant trends, these being observed for an amount of microregions that do not represent relatively significant area percentages in terms of the total area. Regarding the temperature indices, trends significant crescents were verified for TXx, TNx and DTR and decreasing for TNn, for expressive amounts of microregions. Were obtained five sub-regions resulting from the clustering of the maximum values of the SDII, and the results of the indices by homogeneous regions, were shown to be representative in relation to the values by microregions.