Análise dos índices de extremos climáticos e de vegetação por diferença normalizada no Semiárido do Brasil

Abstract

The present study seeks to contribute to the understanding of the impacts of climate change in the Semi-Arid region of Brazil and how it affects the territory and other environmental aspects, as by better understanding this relationship, it will be possible to understand how ecological ecosystems respond to climate change and, thus, take more informed measures to mitigate its impacts. Aiming to analyze the association between climate extreme indices using the principal components technique and the normalized difference vegetation index (NDVI) in the Semi-Arid region of Brazil (SAB). The climate data used was provided by Xavier et al. (2022) and the variables used in the present study are variations, maximum and minimum temperature. NDVI data was collected by the MODIS sensor aboard NASA's TERRA/AQUA satellites. The analysis was carried out primarily by characterizing the rainy and dry periods. Once in certain periods, the analysis of trends in climate index indices was carried out using the principal components technique. Subsequently, Spearman's observation was calculated, with the aim of verifying the association between climate extreme indices and NDVI. There is no intention to understand how these factors interact and influence each other. The first principal component (PC1) reveals information about variations in temperature extremes and frequency of hot days. Regarding NDVI, the results suggest that climatic temperature conditions, especially at night, play a significant role in the relationship between extreme indices, whether in the dry or rainy season. The importance of PC2 and PC3 is also highlighted, which, although the representation of both has a smaller portion of the data variation compared to PC1, reveals information about variations in temperature extremes and frequency of hot days.