The Aerosols, Radiation and Clouds in southern Africa (AEROCLO-sA) field campaign in Namibia: overview, illustrative observations and way forward

New ground-based and aircraft measurements in Namibia to improve the understanding of the role of aerosols on the regional climate of the south east Atlantic Ocean offshore southern Africa. The AEROCLO-sA (AErosol, RadiatiOn and CLOuds in southern Africa) project investigates the role of aerosols on the regional climate of southern Africa. This is a unique environment where natural and anthropogenic aerosols and a semi-permanent and widespread stratocumulus (Sc) cloud deck are found. The project aims to understand the dynamical, chemical and radiative processes involved in aerosol-cloud-radiation interactions over land and ocean and under various meteorological conditions. The AEROCLO-sA field campaign was conducted in August and September of 2017 over Namibia. An aircraft equipped with active and passive remote sensors and aerosol in situ probes performed a total of 30 research flight hours. In parallel, a ground-based mobile station with state-of-the-art in situ aerosol probes and remote sensing instrumentation was implemented over coastal Namibia, and complemented by ground-based and balloon-borne observations of the dynamical, thermodynamical and physical properties of the lower troposphere. The focus laid on mineral dust emitted from salty pans and ephemeral riverbeds in northern Namibia, the advection of biomass burning aerosol plumes from Angola subsequently transported over the Atlantic Ocean, and aerosols in the marine boundary layer at the ocean-atmosphere interface. This article presents an overview of the AEROCLO-sA field campaign with results from the airborne and surface measurements. These observations provide new knowledge of the interactions of aerosols and radiation in cloudy and clear skies in link with the atmospheric dynamics over southern Africa. They will foster new advanced climate simulations and enhance the capability of space-borne sensors, ultimately allowing a better prediction of future climate and weather in southern Africa.