Impact of Climate Change on the Aridity of the São Francisco River Extended Basin, Brazil

Abstract

The future projections disclosed by the Intergovernmental Panel on Climate Change report on the occurrence of variations and changes in the climate. Such changes tend to have a notable impact on the global hydrological cycle, once modifications are made in large-scale precipitation patterns and an increase in the atmosphere's average temperature. The São Francisco River Extended Hydrographic Basin (BESF) located between the Southeast and Northeast regions of Brazil. The Aridity Index (AI) is a supporting instrument for risk and uncertainty management, which can contribute to the water security planning of a territory. Given the above, the objective of this study is to analyze the dryness of the BESF through rainfall and the change of extreme temperatures obtained through the climate models of CMIP6 and CORDEX. For this analysis, the Aridity Index (AI) was calculated and the AI results obtained from the climate models were compared with the reference data from the Climatic Research Unit (CRU). The CMIP6 and CORDEX models indicate an increase in Potential Evapotranspiration for all scenarios, with divergence in relation to precipitation. Both models, CMIP6 and CORDEX, presented good performance in representing the IA when compared with the CRU. When comparing the results obtained by both models, it is possible to observe that the CORDEX data are more recommendable for BESF, due to the spatial resolution of the indices obtained by their models.

Keywords
precipitation; temperature; aridity index