Ajoku, O., A. J. Miller and J. R. Norris, 2020:
Impacts of aerosols produced by biomass burning on the
Stratocumulus-to-Cumulus Transition in the equatorial Atlantic
Journal of Geophysical Research-Atmospheres, sub judice.
The impact of aerosols produced by biomass burning on the stratocumulus-to-cumulus transition (SCT) in the
equatorial Atlantic is studied using satellite-based and reanalysis data for the month of June. The month of June is
highlighted because it represents monsoon onset as well as the largest sea surface temperature gradient in the
summer, which is the peak season of tropical African biomass burning. Boundary layer deepening and increasing
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 near maximum aerosol loading. These effects
combine to extend the SCT in space during increased aerosol loading episodes.