Variability of rainfall and associated mechanisms across the Brazilian Legal Amazon

Keywords: climate, rainfall, land-atmosphere interactions, amazon
Session Type: Virtual Paper Abstract
Day: Sunday
Session Start / End Time: 2/27/2022 09:40 AM (Eastern Time (US & Canada)) - 2/27/2022 11:00 AM (Eastern Time (US & Canada))
Room: Virtual 48

Abstract

The Amazonian rainfall dynamics are influenced by land use, atmospheric systems, and climatic modes. Modeling studies have projected a drier climate with the ongoing deforestation in the Amazon, but observational evaluation of the variability of rainfall and deforestation patterns has been limited. The study aims to analyze spatiotemporal trends in rainfall between 1981 and 2020, in relation to El Niño - Southern Oscillation (ENSO), deforestation, and evapotranspiration (ET) in the Brazilian Legal Amazon (BLA). Rainfall data derived by calibrating the Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) dataset with a rain gauge network, and statistical methods such as Mann-Kendall test, were used to identify significant changes over time and space. We used the NOAA ENSO index, satellite-based land cover data Mapbiomas and two ET datasets (MODIS and ERA5) to evaluate their interactions and trends. Our results showed that rainfall within the domain was highly variable and significant (p ≤ 0.05) trends generally indicated that the rainfall extremes were intensified. Deforestation along old frontiers particularly in areas where the impact of ocean warming on rainfall is weak may affect local hydroclimatic balances.