An interannual Antarctic sea‐ice ‐ocean mode

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Abstract
By means of a global coupled sea‐ice‐ ocean model we propose an oscillating mechanism in the Antarctic region with the same frequency as that associated with the Antarctic Circumpolar Wave (ACW) [White and Peterson, 1996]. Since our model is forced from the atmosphere with climatological monthly data with an annual repeat cycle, our oscillation suggests 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 Ocean sea‐ice, except for the case where higher rates of new‐ice production and thus Antarctic Bottom‐Water (AABW) formation are enforced. The present results imply that the sea‐ice ‐ocean system itself may produce regional oscillations at a 4‐year period in climatic conditions of relatively weak rates of AABW formation, which may contribute to regionally sustaining the ACW pattern.