The distribution of surface anticyclones across the Southern Hemisphere from the NCEP reanalysis

We present a new climatology of the system density of surface anticyclones over the Southern Hemisphere. The climatology is based on 40 years of data and will be presented for each season. The analyses upon which the anticyclones are extracted are the six-hourly NCEP reanalyses, covering the period 1958-97. The anticyclones are obtained from these analyses by the application of a sophisticated, automated vortex tracking scheme.

In all seasons the maximum anticyclonic density lies between 30 and 40oS. In each of the three ocean basin the maximum density is seen to occur on the eastern side. A significant exception to this occurs in the Indian Ocean, particularly in winter when the maximum density if found in the central and western part of the basin. Regional features of interest will be discussed. Included among these are the high density of anticyclones to be found in the Great Australian Bight and the Tasman Sea in all seasons except winter.