Sensitivity of the southern hemisphere circulation to leads in the Antarctic pack ice

Abstract To assess the sensitivity of the southern hemisphere circulation to changes in the fraction of open water in the sea ice we have conducted four experiments with a July 21‐wave General Circulation Model (GCM) with this fraction set to 5, 50, 80 and 100%. The mean surface temperatures and the...

Full description

Bibliographic Details
Published in:Quarterly Journal of the Royal Meteorological Society
Main Authors: Simmondsxs, Ian, Budd, W. F.
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 1991
Subjects:
Online Access:http://dx.doi.org/10.1002/qj.49711750107
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fqj.49711750107
https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.49711750107
Description
Summary:Abstract To assess the sensitivity of the southern hemisphere circulation to changes in the fraction of open water in the sea ice we have conducted four experiments with a July 21‐wave General Circulation Model (GCM) with this fraction set to 5, 50, 80 and 100%. The mean surface temperatures and the surface atmospheric temperatures over the sea ice increased as the water fraction increased and the largest changes were simulated adjacent to the coast. Significant anomalies in the surface heat fluxes, particularly those of sensible heat, accompanied the decrease in the sea ice concentration. Substantial atmospheric warming was simulated over and in the vicinity of areas in which leads were considered. In all but one experiment there were anomalous easterlies between about 40 and 60°S with westerly anomalies further to the south. The surface pressure at high latitudes appears to change in a consistent fashion with the fraction of open water, with the largest changes occurring in the Weddell and near the Ross Seas. Some of the feedbacks which may enhance the responses here, but which are not included in our model, are discussed.