Southern Hemisphere winter extratropical cyclone characteristics and vertical organization observed with the ERA-40 data in 1979-2001

Abstract

The mean characteristics and trends of Southern Hemisphere (SH) winter extratropical cyclones occurring at six levels of the troposphere over the period 1979-2001 have been investigated using the 40-yr ECMWF Re-Analysis (ERA-40) data. Cyclonic systems were identified with the Melbourne University cyclone finding and tracking scheme. This study sh ows that mean sea level pressure (MSLP) cyclones are more numerous, more intense, smaller, deeper, and slower moving than higher-level cyclones. The novel vertical tracing scheme devised for this research revealed that about 52% of SH winter MSLP cyclones have a vertically well organized structure, extending through to the 500-hPa level. About 80% o..