Observed Impact of Smoke Aerosols on the Stratocumulus-to-Cumulus
Transition in the Equatorial Atlantic
Abstract
The impact of smoke aerosols on the stratocumulus-to-cumulus transition
(SCT) in the equatorial Atlantic is studied using observation-based data
for the month of June. Boundary layer deepening and increasing sea
surface temperatures put the location of the SCT within the Gulf of
Guinea. Satellite retrievals indicate that the bulk of aerosols occurs
at 1500m in altitude, either above or below the boundary layer depending
on latitudinal position. Changes in smoke loading over the Gulf of
Guinea due to greater transport from regions of biomass burning leads to
increased low-level cloud cover and lower surface temperatures when
aerosol optical depth anomalies exceed 0.1. Similar results opposite in
sign are obtained during lesser transport. Further south, we find
significant changes to cloud top height, tropospheric stability and
moisture availability. These effects combine to alter the SCT during
increased loading, which is consistent with previous modeling studies.