Ajoku, O., A. J. Miller and J. R. Norris, 2021:
Impacts of aerosols produced by biomass burning on the
Stratocumulus-to-Cumulus Transition in the equatorial Atlantic
Atmospheric Science Letters, 22, e1025.
Abstract.
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
near 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
southern Africa leads to increases in low-level cloud cover above cloud decks and decreases
when mixed within the boundary layer. Further south, we find significant changes to
temperature, cloud top height, tropospheric stability and moisture availability near maximum
aerosol loading. In addition, changes in vertical velocity during dirty conditions further reinforce
changes in tropospheric stability. These effects combine to shorten the SCT in space during
increased aerosol loading episodes.
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