Eastward propagation of the intraseasonal variability of sea ice and the atmospheric field in the marginal ice zone in the Antarctic

Abstract

We investigate the intraseasonal variability of the sea-ice concentration in the Antarctic marginal ice zone(MIZ), using daily sea-ice and atmospheric data for eight winters (1990-97). From 5-31 day band-pass filtered sea-ice concentration data for the whole sea-ice region, it is clearly shown that the lower-latitude MIZ has the maximum intraseasonal variability, taking the form of a narrow, circumpolar belt with alternately increasing and decreasing areas. This coherent pattern propagates eastward as a wave. A similar wave also appeared for the atmospheric field around the MIZ. The eastward propagating waves for sea-ice and the atmosphere have almost same properties, a wavenumber of 2-4, a period of 10-15 days, and a phase velocity of 10-18 degress/day. The common propagating signatures suggest a close relationship between the intraseasonal variability of sea-ice and atmospheric field in the Antarctic MIZ in winter.