Distribution and temporal variability of 500 hPa cyclone characteristics in the Southern Hemisphere

Abstract

A 40 year period (1958-97) of US National Centers for Environmental Prediction reanalysis data has been used to diagnose the behaviour and variability of 500 hPa extratropical cyclones for the Southern Hemisphere using a Lagrangian perspective. The 'finding' and 'tracking', of these systems were performed using a fully automated scheme. Seasonal distributions of system density, cyclone formation (cyclogenesis), decay (cyclolysis), cyclone centre velocity and intensity/strength are presented. System density is shown to exhibit a maximum in the surface circumpolar trough region and over the Antarctic continent. A broad band of enhanced cyclone system density was evident across the South Pacifi..