AN INTERANNUAL ANTARCTIC SEA-ICE - OCEAN MODE

By means of a global coupled sea-ice - ocean model we propose an oscil lating mechanism in the Antarctic region with the same frequency as th at associated with the Antarctic Circumpolar Wave (ACW) [White and Pet erson, 1996]. Since our model is forced from the atmosphere with clima tological monthly data with an annual repeat cycle, our oscillation su ggests an internal mode of the sea-ice - ocean system rather than one which is dictated by global links through the atmosphere. This mode is robust for a wide range of parameterisation and forcing of Southern O cean sea-ice, except for the case where higher rates of new-ice produc tion and thus Antarctic Bottom-Water (AABW) formation are enforced. Th e present results imply that the sea-ice - ocean system itself may pro duce regional oscillations at a 4-year period in climatic conditions o f relatively weak rates of AABW formation, which may contribute to reg ionally sustaining the ACW pattern.