AErosol RadiatiOn and CLOuds in Southern Africa – AEROCLO-SA

The core of the ground-based operations of project will occur through the deployment of PEGASUS mobile station of the LISA deployed at the lHenties Bay surface monitoring station (22.09°S, 14.26°E). PEGASUS is composed by two modules dedicated to sampling and characterization of aerosol and trace gases, in order to documentthe quality of the air masses and their age.
The coordinated implementation of several research aircraft from the coastal airport of Walvis Bay (22°6’S, 14°30’E), 50 km south of the supersite of HBAO, will provide with the aerosol-cloud-radiation interaction measurements at the subcontinental scale offshore and inland Southern Africa. Flights will consists in vertical profiles below, within and above the clouds and the aerosol layers, and in long-legs at various altitudes above the ground-based sites and as often as possible in conjunction with geostationary (e.g. SEVIRI) and polar-orbiting satellite overpasses (e.g. CALIPSO, MODIS, MISR) to map out the spatial aerosol distribution and variability. The F-20 will fly from Walvis Bay at about 12 kilometres to provide with the 3-D representation of the aerosol and cloud fields both over land and over sea.
The retrieval of key aerosol parameters (e.g., aerosol optical depth, size distribution, vertical profiles) needed to constrain the aerosol direct and semi-direct radiative effects both over land and over ocean, in clear and cloudy skies, will use a number of satellite products. The key science questions of the project will be addressed in the international framework using models that represent a wide range of both complexity and spatial scales. The French contribution will target the regional scale using the regional climate model RCM (RegCM) that incorporates “on-line” mineral dust and biomass burning aerosol schemes.

Results will become available after the field campaign conducted in Aug-Sept 2017

The project focuses on the role of aerosols on clouds and radiation. The majour outcomes and perspectives of this work will become available after the field campaign in Aug-Sept 2017.

The scientific production will become available after the field campaign in Aug-Sept 2017.

The representation of clouds, aerosols and cloud-aerosol-radiation interaction remain the largest uncertainties in climate change, limiting our ability to accurately reconstruct and predict future climate change. The South East (SE) Atlantic is a region where high atmospheric aerosol loadings (from biomass burning, mineral dust, marine origin) and semi-permanent stratocumulus cloud are co-located. This area provides a unique natural laboratory for studying the full range of aerosol-radiation and aerosol-cloud interactions and their perturbations of the Earth’s radiation budget. Aside the fundamental knowledge that can be gained from the study of this environment, these perturbations of the radiative systems occurring in SE have a significant impact, not just locally but also via global teleconnections on wider changes in climate. There have never been detailed although measurements of the combined cloud-aerosol-radiation system over the SE Atlantic are crucial in constraining the current generation of large eddy simulation, numerical weather prediction and climate models.
The AErosol RadiatiOn and CLOuds in Southern Africa (AEROCLO-SA) project proposes a break-through study focusing on the South East (SE) Atlantic off the western coast of southern Africa providing with a novel evaluation of the interactions between aerosols, clouds and radiation and their representation in global and regional models.
AEROCLO-SA will deliver a wide range of airborne, surface-based and satellite measurements of clouds, aerosols, and their radiative impacts to
1) improve representation in models of absorbing and scattering aerosols
2) reduce uncertainty of the direct, semi-direct and indirect radiative effect, and their impact on stratocumulus clouds;
3) challenge satellite retrievals of cloud and aerosol and their radiative impacts to validate and improve algorithms;

AEROCLO-SA is the French contribution in the framework of a very high level international, synergistic project. Aside the French contribution (5 leading laboratories from Universities and CNRS), it gathers partners
- from the UK (Met Office, Univ. of Reading, Manchester, Oxford, …) within the CLARIFY-2016 project );
- from the USA within the NSF LASIC project (22 US universities and research labs) and within the US NASA ORACLES (5 NASA research centers and 8 Universities);
- and from southern African Universities under the umbrella of the ARSAIO research initiative (CNRS/NRF).
AEROCLO-SA includes ground-based and airborne measurements, and modelling. The present project aims at funding the airborne part of the French contribution 1/ to allow the French community who was part of the overall strategy from the very beginning to eventually participate to its implementation during the international field campaign 2/ to gather unique datasets 3/ to participate the valorization of the international dataset.