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OSUG - Terre Univers Environnement OSUG


par Administrateur Un - 15 février 2011 - ( maj : 15 février 2011 )

Environment and climate of high latitude regions are in very fragile equilibria and very sensitive to any perturbations. The onset of the Antarctic ozone hole has clearly highlighted the fragile equilibrium of the atmosphere, even in these areas located far away from industrialised regions. High latitude regions, the cold reservoir of the Earth climate system, also experience numerous regional climatic feedbacks (i.e. changing albedo), making them to the most sensitive regions to climate change. Other important feedbacks are far more complex and yet not well understood. In particular, atmospheric aerosol may cause a regional climatic feedback via its interaction with solar radiations and cloud microphysics. At high latitudes atmospheric aerosol originates mainly from the oxidation of marine biogenic sulphur emissions (dimethyl sulphide, DMS) which need to be better understood.

A better understanding of the role of the snowpack on the oxidative capacity of the atmosphere at the scale of the East Antarctic plateau (representing more than half of the Antarctic continent and where deep ice cores have been extracted) is needed, and calls for the establishment of parameterizations in view to simulate future changes. That motivates this project, which aims to establish the present-day oxidative capacity of the atmosphere over the East Antarctic plateau, to investigate its influence on the coastal East Antarctica region, and to forecast its future change in view of the future recovery of stratospheric ozone layer over Antarctica. Intensive field campaigns dedicated to relevant atmospheric chemical species and key physical parameters for re-emission from the snow will be conducted at the two French sites (DDU and Concordia) whose the geographical positions appear to be ideal with respect to the objectives of OPALE. Integration of data will be done by using a snow physics and chemistry model, and a photochemical box model that can be coupled to the trajectory/dispersion model.

This project is coordinated by S. Preunkert. Other LGGE participants are M. Legrand, J. Savarino, B. Jourdain, F. Dominé, H.-W. Jacobi and C. Genthon.

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