Evaluation of environmental degradation on Biomes in Brazilian Northeastern

In recent years, due to irregular rainfall, several regions across the globe suffer from some type of environmental degradation. Depending on the degree of intensity, they can lead to a series of socioeconomic problems, both regional and national. One of the most emblematic types of degradation today is the desertification development process, resulting in a combination of factors: anthropic, climatic, and/or environmental. In an attempt to understand the behavior of these impacts, this work evaluated the degradation process based on the Aridity Index (AI) on biomes located in the Brazilian Northeast (Caatinga, Atlantic Forest, Amazon, and Cerrado). The AI consists of the relationship between the use of evapotranspiration (in this case, the Thornthwaite estimation method) and precipitation. The data used correspond to the product Climatologies at high resolution for the earth's land surface areas (CHELSA), which have a spatial resolution of 1km x 1km and temporal resolution on a monthly scale, from 1979 to 2013. In addition, it was found that the AI behavior during years of the occurrence of the El Niño-Southern Oscillation (ENSO) warm phase, the El Niños. The identification of El Niño episodes was based on the Oceanic Niño Index (ONI) climate proxy, characterized by the Equatorial Pacific region known as the Niño 3.4 region, from which the years 1983, 1993, 1998, and 2012 were selected. AI results point out different behaviors between the biomes, mainly over the south of the northeastern Cerrado and the Caatinga, motivated by the strong variability of rainfall in the respective regions. The Caatinga stands out, which exhibited a large part of its area was classified as arid (AI between 0.05 – 0.20) and hyper-arid (AI < 0.05), mainly in 2012. The Amazon and biomes, on the other hand. Atlantic Forest has areas classified as semi-arid (AI < 0.5). El Niño had a reduction in the AI values, motivated by the long periods of drought and irregular rainfall that negatively impacted the semi-arid of the Northeast region.