Impacts of aerosols produced by biomass burning on the stratocumulus‐to‐cumulus transition in the equatorial Atlantic

Abstract

The impact of aerosols produced by biomass burning on the stratocumulus-tocumulus transition (SCT) in the equatorial Atlantic is studied using satellitebased 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 occur near 1,500 m 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.

West African monsoon precipitation impacted by the South Eastern Atlantic biomass burning aerosol outflow

“…In this study, we describe mechanisms by which SABB aerosols are likely to modulate the WAM dynamics and precipitation over southern West Africa. Particularly, these results provide causal relationships compatible with the recent observation-based analysis of 9,31 , outlining notably a link between inter-hemispheric aerosol transport, AOD anomaly, and negative precipitation anomaly in the southern WAM coastal area. Using model sensitivity tests, we furthermore suggest that, at a climatic scale, SABB aerosol-induced convection and precipitation suppression in the WAM coastal area is primarily a result of a regional scale dynamical adjustment triggered by the large positive SABB aerosol radiative forcing in the SEA outflow and over the stratocumulus deck region.…”

Impacts of Biomass Burning in Peninsular Southeast Asia on PM2.5 Concentration and Ozone Formation in Southern China During Springtime—A Case Study

“…Biomass burning (BB) emits abundant trace gases and aerosols, affecting not only air quality by involving atmospheric photochemistry and aerosol‐photolysis interactions (API), but also regional weather and climate by aerosol‐radiation interactions (ARIs) and aerosol‐cloud interactions (ACI) over source and downwind areas (Ajoku et al., 2021; Booth et al., 2012; Guo et al., 2016; Li et al., 2016; L. Liu et al., 2020). Intense BB occurs frequently in spring in peninsular Southeast Asia (including Myanmar, Thailand, Laos, Vietnam, and Cambodia, hereafter referred to as PSEA) because of slash‐and‐burn and land‐clearing practices before the local growing season, the start date of which ranges from March to May (Fox et al., 2009; Jian & Fu, 2014; Suepa et al., 2016).…”

Using Multi-Platform Satellite Observations to Study the Atmospheric Evolution of Brown Carbon in Siberian Biomass Burning Plumes

“…5 Wavelength dependence of k for organic aerosol. 6 Hygroscopicity parameter. 7 The most probable value (estimated as a function of the BC/OA ratio according to Lu et al [74]) of the wavelength dependence.…”

“…Aerosol particles emitted from open biomass burning (BB) constitute a major fraction of aerosol emissions from combustion sources and, as such, contribute significantly to the radiative budget of the atmosphere and the aerosol radiative forcing, both at global and regional scales, through the direct aerosol-radiation interaction [1][2][3] by impacting the formation and lifetime of clouds [4][5][6] and affecting the carbon fluxes in ecosystems [7]. The direct interaction of BB aerosol with solar light is mostly determined by a balance between light scattering by organic aerosol (OA) and light absorption by black carbon (BC) and brown carbon (BrC), with the latter being comprised of a complex mixture of lightabsorbing organic compounds.…”