The Henties Bay Aerosol Observatory (HBAO):
from aerosol monitoring to climate change in Southern Africa
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The representation of clouds, aerosols and their interactions with radiation are key climate uncertainties according to the recent Intergovernmental Panel on Climate Change (IPCC) assessment report. These uncertainties limit our ability to accurately reconstruct and predict future climate change. Southern Africa is the main global source of biomass burning aerosols, a large source of mineral dust, and a major source of anthropogenic sulfate aerosols originating from the power plants in the industrial Highveld in South Africa. Because anticyclonic circulation favors continental-scale transport, these aerosols are found in high loads over the South East Atlantic between 5° and 25°S off Namibia, where an almost permanent and wide-spread stratocumulus deck topping the marine boundary layer is found at about 850 hPa. The South East Atlantic is henceforth the perfect natural laboratory for studying the full range of aerosol-radiation-cloud interactions and their perturbations of the Earth’s radiation budget. In this framework, in 2011 the Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA) in Créteil (France), the NorthWest University (NWU) in Potchefstroom (South Africa) and the San Nujoma Marine & Coastal Resources Research Centre (SANUMARC) of the University of Namibia, have established the Henties Bay Aerosol Observatory (HBAO) in the framework of the Bilateral research Project “Atmospheric Research in Southern Africa and the Indian Ocean” (GDRI-ARSAIO) between the French (CNRS and the South African NRF). The HBAO is located at the SANUMARC university campus at Henties Bay, along the Namibian coast (22.09°S, 14.26°E, 20m). Present measurements include the aerosol mass concentration and the aerosol black carbon concentration, the ozone mixing ratio and the basic meteorological parameters. In the same framework, new observations by a sunphotometer of the AErosol RObotic NETwork (AERONET, NASA/PHOTONS) program has been established at the Gobabeb Research and Training Centre , in the Namib Desert. We now head towards 2016, when a synergistic international initiative between the French, British and American scientific communities working on the interactions between aerosols, clouds, and radiation, plan an experimental campaign based on surface, aircraft, and satellite observations.
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