Anomalous temperature in North Tropical Atlantic linked to Brazilian Cerrado fires

Abstract

Brazilian Cerrado has the largest annual burned area (BA) in South America, with strong interannual variability. However, there is limited understanding of which climatic drivers lead to the interannual variability of Cerrado fires. This study found sea surface temperature anomalies (SSTAs) in the North Tropical Atlantic (NTA) are positively correlated with the Cerrado BA. Positive SSTAs over the NTA modulate the intertropical convergence zone (ITCZ) position, which suppresses atmospheric convection over the Cerrado region. While NTA SSTA peaks March, the precipitation reduction in Cerrado is pronounced during June–August, since the ITCZ shifts northward and the local monsoon weakens. This leads to moisture deficits for the following months, significantly enhancing fire activity in August–October. This result implies NTA can exert an independent influence on Cerrado in addition to the traditionally considered factor, the El Niño–Southern Oscillation. This improves the predictability of fire activity because NTA precedes the fire season by 7 months.