The importance of large scale sea ice drift and ice type distribution on ice extent in the Weddell Sea

In austral winter large parts of Antarctic Seas are covered by sea ice. This modifies the \nexchange of heat, mass and momentum between ocean and atmosphere. The knowledge of ice \nextent and its variability is necessary for an adequate simulation of those fluxes and thus for \nclimate modelling. The goal of this study is the observation of interannual and seasonal ice \nextent variations and their underlying causes. Variability is analysed by using monthly means \nof microwave and scatterometer satellite data. Results are correlated with ice drift variations \ncalculated from a Finite Element Sea ice-Ocean Model (FESOM) and with satellite derived \nsea ice drift products to determine the dependency of ice extent on sea ice drift. An additional \ncause for changing ice extent could be the variability of ice type distribution, i.e. the \ncontribution of first and second year ice to the total ice covered area. These ice types are \ndetermined on monthly time scales from scatterometer satellite data. Ice class distribution and \nsea ice drift variability are compared with the characteristics and variability of the Southern \nAnnular Mode (SAM) to evaluate the relative importance of different sea ice parameters for \nshaping Weddell Sea ice extent and its variability.