Simulation of the direct and semidirect aerosol effects on the southern Africa regional climate during the biomass burning season

摘要: [1] The regional climate model RegCM3 was used to simulate the direct and semidirect radiative effects of biomass burning dust aerosol over southern Africa during austral winter season. Simulated aerosols were found induce changes in surface fluxes atmospheric dynamics. Clear-sky forcing decreased by up −60 W/m2 main region, resulting turbulent PBL height as well reduced temperatures. The positive temperature bias western half subcontinent thus reduced. Radiative absorption resulted diabatic warming atmosphere, peaking near 700 hPa at a rate 1°C/d. cooling heating altitude stabilized lower troposphere below hPa. Above hPa, stability equatorial region between 5°N 5°S through an elevated heat pump mechanism, enhancing deep convection precipitation. branch African Easterly Jet enhanced shifted southward, likely result gradient induced both reduction solar radiation reaching precipitation-induced region. Daily-scale outflow events southwest Indian Ocean also investigated, these occurring with passage westerly wave. It that loading baroclinicity along leading edge frontal system, intensifying narrowing band precipitation this zone.