Analysis of Climate Extreme Indices in the MATOPIBA Region, Brazil

The identification of the spatial and temporal variability of meteorological variables, as well as of climate extreme events, such as the duration of dry spells, duration of warm spells and rainfall intensity, is crucial for agrometeorological studies, since they can negatively impact yields through the exposure of the crop to critical conditions. Thus, this study analyzed trends in 23 rainfall and temperature climate extreme indices in the MATOPIBA region, currently a strategic area for investments in soybean cultivation, playing a major role in ensuring global food security. Daily time series of rainfall and temperature (maximum and minimum) data in the 1980–2013 period were used, arranged in a 0.25° × 0.25° grid, covering 963 points over the studied region. The data set was submitted to cluster analysis, the Mann–Kendall non-parametric test and extremes indices and their trends were estimated through the RClimdex software. Trends in rainfall rates and in mean, maximum and minimum temperatures were evaluated for each cluster and shifts from the climatological patterns of these variables were detected. Only some of the rainfall climate extreme indices presented significant increase and/or decrease in the CI and CII subregions. On the other hand, there was a significant increase in almost all temperature climate extreme indices in all clusters. The persistency of these trends may lead to impacts on soybean cultivation in the MATOPIBA region, and therefore these results are crucial for the elaboration of strategies for agricultural planning.