Resposta Do Índice De Vegetação Evi a Anomalias De Precipitação No Estado Da Paraíba

Abstract

The climatic conditions of a given region are fundamental in the development of an ecosystem, as it is made up of biotic (living beings) and abiotic (non-living) factors. Changes in the same caused by anthropic action, as well as of natural origin, can directly affect these factors. In the case of vegetation, when it is removed indiscriminately, significant changes in the climate may occur, also aggravating the erosion processes that degrade the soil. In this context, monitoring the vegetation is of fundamental importance in preserving ecosystems and life as a whole. Therefore, we sought to evaluate the spatiotemporal pattern of the annual and monthly response of vegetation to rainfall anomalies in the state of Paraíba in the period 2003-2018. Data from the Enhanced Vegetation Index (EVI) and the Normalized Difference Vegetation Index (NDVI) of the monthly product MYD13A3 from the MODIS/Aqua satellite, with a spatial resolution of 1 km, annual and monthly rainfall totals (PRP) obtained from the site were used. of the Executive Agency for Water Management of the State of Paraíba (AESA). Annual linear correlation and response time of vegetation to monthly PRP anomalies were determined using the Principal Component Analysis (PCA) technique. The linear correlation between the annual series of PRP, EVI and NDVI showed a very expressive correlation coefficient of 0.92 for EVI and 0.90 for NDVI at a significance level of α=0.05. The joint temporal analysis between EVI and PRP, in regions with vegetation cover predominantly in the Caatinga biome, the EVI values increased after a significant rainfall with a lag of one month. In the other regions, the temporal lag occurs in the period of two months between the precipitation and the response of the vegetation.