Biomass Burning Effects on the Western Africa Climate: the NASA-Unified WRF Simulation for 9–16 August 2006 during the AMMA Special Observing

Abstract:

Western Africa climate could be under the influence of various type aerosols. Biomass burning aerosols, mostly caused by savanna fires, particularly cause large uncertainty in deducing aerosol impacts on the climate because of the complicated anthropogenic and natural factors. We have investigated the aerosol impacts using a state-of-the-art regional atmospheric modeling system in fully coupled simulations of aerosols, radiation and cloud-precipitation components. The NASA-Unified WRF (NU-WRF) version 7, “Arthur”, is employed in a form using the GCE cloud microphysics directly tied to aerosol number concentration forecasted in the GOCART aerosol emission and transport module. Realistic aerosol surface emission and loading from the domain are provided from PREP-CHEM-SRC system and the MERRA aerosol reanalysis. LIS-spinup system is used to initialize the high-resolution heterogeneous land surface states instead of using interpolation from coarser reanalysis data. We have conducted several sensitivity tests for the case of 9–16 August 2006 during the AMMA special observing period (SOP) peak-monsoon phase to evaluate various aerosol impacts on the regional radiative balance and cloud-precipitation patterns through direct/indirect effects and feedback to the land surface process.