Hot spots and anomalies of CO2 over eastern Amazonia, Brazil: A time series from 2015 to 2018

Abstract

The easternmost Amazon, located in the Maranhão State, in Brazil, has suffered massive deforestation in recent years, which has devastated almost 80% of the original vegetation. We aim to characterize hot spots, hot moments, atmospheric carbon dioxide anomalies (Xco2, ppm), and their interactions with climate and vegetation indices in eastern Amazon, using data from NASA's Orbiting Carbon Observatory-2 (OCO-2). The study covered the period from January 2015 to December 2018. The data were subjected to regression, correlation, and temporal analysis, identifying the spatial distribution of hot/cold moments and hot/cold spots. In addition, anomalies were calculated to identify potential CO2 sources and sinks. Temporal changes indicate atmospheric Xco2 in the range from 362.2 to 403.4 ppm. Higher Xco2 values (hot moments) were concentrated between May and September, with some peaks in December. The lowest values (cold moments) were concentrated from November to April. SIF 771 W m−2 sr−1 μm−1 explained the temporal changes of Xco2 in 58% (R2 adj = 0.58; p < 0.001) and precipitation in 27% (R2 adj = 0.27; p ≤ 0.001). Spatial hot spots with 90% confidence were more representative in 2016. The maximum and minimum Xco2 (ppm) anomalies were 6.19 ppm (source) and −6.29 ppm (sink), respectively. We conclude that the hot moments of Xco2 in the eastern Amazon rainforest are concentrated in the dry season of the year. Xco2 spatial hot spots and anomalies are concentrated in the southern region and close to protected areas of the Amazon rainforest.