Sea‐ice and the antarctic winter circulation: A numerical experiment

• Published in: Quarterly Journal of the Royal Meteorological Society
• Main Authors: Mitchell, J. F. B., Hills, T. S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1986
• Subjects: Antarctic; The Antarctic; Simmonds; Antarc*; Sea ice
• Online Access: http://dx.doi.org/10.1002/qj.49711247404; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fqj.49711247404; https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.49711247404

Abstract A numerical experiment has been conducted to test the sensitivity of a global general circulation model to changes in sea‐ice extents in the antarctic during winter. Three 112‐day integrations have been made in which all the antarctic sea‐ice poleward of 66°S was removed, commencing on 10 June in the second, third and fourth years of a control integration. There was a large increase in sensible heat flux over the anomaly, a warming over the antarctic confined to the lowest atmospheric layer, and a 2ms −1 reduction in the westerly flow around the periphery of the (new) sea‐ice margin, in broad agreement with a previous study by I. Simmonds. The increased heating over the anomaly was accompanied by a decrease in surface pressure which was not found by Simmonds, and possible explanations of this discrepancy are considered. The results are related to previous work on the effect of increased CO 2 using prescribed changes in sea surface temperature and sea‐ice extents. The implications of the results for the parametrization of the heat flux through sea‐ice cover, and for coupled ocean‐atmosphere models are discussed.