The role of the non-axisymmetric Antarctic orography in forcing the observed pattern of variability of the Antarctic climate

Abstract

The pattern of inter-annual variability in the atmospheric circulation around Antarctica has a maximum over the Amundsen-Bellinghausen Sea (ABS), which is particularly strong during the winter (June, July and August). By using an atmosphere-only general circulation model the causes of this maximum have been investigated. In particular we study the effect of the non-axisymmetric nature of the local surface forcing (sea surface temperatures, sea ice and orography) by imposing axi-symmetric forcing fields at high southern latitudes. The results of these experiments show that the non-axisymmetric nature of the Antarctic orography is sufficient to explain the variability maximum in the ABS.