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Can biomass burning aerosol induced surface cooling and atmospheric teleconnection be amplified through sea surface temperature-cloud feedback over the Southeast Atlantic?

Presentation Date
Wednesday, December 13, 2023 at 4:10pm - Wednesday, December 13, 2023 at 4:20pm
MC - 3004 - West



Biomass burning (BB) aerosols exert a strong surface cooling effect over the southeast Atlantic (SEA) via aerosol-radiation and aerosol-cloud interactions. The reduction of the sea surface temperature (SST) can trigger the SST-low cloud feedback. Whether this feedback can amplify the local surface cooling effect and trigger an atmospheric teleconnection to the tropical Pacific is examined. The modeling results from the Community Earth System Model version 2 (CESM2) demonstrate that counterintuitively the cloud radiative effect (CRE) caused by the BB aerosols is weaker when SST-low cloud feedback is considered compared to the fixed-SST simulation where the feedback is not considered (-2.99 W m-2 vs. -4.79 W m-2). This is caused by 1) stronger sea breeze due to larger sea-land temperature contrast causing less smoke transport over SEA and 2) less moisture supply from surface due to colder SST. Changes in SST also lead to counterclockwise rotation of ocean circulation anomalies. Consequently, the excess heat transport from the equator reverses the direction of SST-cloud feedback in this region. We also examine how SST oscillation in SEA caused by the presence of BB aerosols can trigger a La Niña-like climate response through modulating the strength and location of the Walker circulation

Atmospheric Sciences
Funding Program Area(s)