LAUSR

Prolonged drought periods over large regions can affect a wide range of biomes and vegetation primary productivity. Here, we evaluated the long-term response of Normalized Difference Vegetation Index (NDVI) from Moderate Resolution Imaging Spectroradiometer (MODIS) in two administrative regions in Brazil, Northeast (NE) and Southeast (SE). Comparisons were made with ancillary Global Land Data Assimilation System (GLDAS) hydrometeorological data, focusing on a recent prolonged drought period from 2012 to 2015, which affected both regions. We found that the drought significantly impacted vegetation cover in large areas in NE dominated by a semiarid climate, whereas in SE region drought effect in vegetation was less pronounced and just some patches of stressed vegetation was identified. Regarding individual biomes in both regions, Caatinga, a unique tropical dry biome located in the center of semi-arid in the NE region, and the Northern portion of Atlantic Forest, an evergreen rain forest in the Brazilian coast, were severely impacted. Based on a time series analysis using breaking point tests, we revealed that after four stable years, an intense greening drop occurred, followed by a strong successive recovery pulses during the mentioned drought. Using the singular value decomposition (SVD) technique, we identified, among the hydrological variables, that precipitation and soil moisture better explain NDVI spatiotemporal variability, whereas the evapotranspiration pattern is not directed associated to the index, mainly in the SE region. Our results indicate that the covariability between NDVI and hydrometeorological variables should be better explored to monitor and forecast future droughts over different biomes in Brazil.