THE INFLUENCES OF ATMOSPHERIC HALF-YEARLY CYCLE ON THE SEA ICE EXTENT IN THE ANTARCTIC

The relationship between sea ice and weather, one of the least known components of the climatic system, could be an important factor for the climate of high latitudes. The annual cycle of the sea ice extent is characterized by an asymmetric development, with the sea ice area slowly advancing toward the equator in the winter and rapidly retreating in summer. In this study the seasonal asymmetric behavior of ice extent and the changes in sea ice concentration are shown to be linked to the atmospheric convergence line (ACL) around Antarctica. It is found that the relative positions of the ACL characterized by the half-year cycle exert a strong influence upon the mean movement of the sea ice. It is also observed from the investigations of the areal concentration of the sea ice that a decrease in ice concentration prior to the sea ice retreat is needed for a rapid retreat. -Authors