ABSTRACT
Averaged over the whole year, the temperatures of the layer 300–900 mb (ca 3–9 km) in interior Antarctica are 11–12°C colder than those in the Arctic. As a consequence, the circumpolar vortex in the upper troposphere and lower stratosphere above the Antarctic is much deeper than above the Arctic, the intensity of the mid-latitude westerlies is higher and the tropical Hadley circulation of the southern hemisphere extends, during the greater part of the year, beyond the equator, thus suppressing the northern Hadley cell. The physical causes of this marked asymmetry of the global atmospheric circulation will be discussed.
Arctic and Antarctic climatic evolution could be essentially independent, as indicated by recent development. The coincidence of major Milankovich episodes can be interpreted as resulting from the seasonal parallels between the development of drifting ice of the Subantarctic and summer anomalies of the essentially continental climate of the Subarctic.
The role of possible Antarctic surges for the climatic evolution in the last 40 × 106 years will be discussed, as well as the role of the slow drift of Antarctica onto its isolated polar position.
