Transient response of the Southern Hemisphere subtropical jet to tropical forcing

Abstract

This jet is a main feature of the winter time circulation extending over Australia and the western Pacific Ocean. An intensification of this jet was observed for 8 August, with peak values of 93m s-1. Satellite pictures and daily precipitation amounts revealed that the 6-8 August period was characterized by extensive rainfall in the tropics. The case study and GCM simulations suggest the following time scale of response of subtropical latitudes to tropical latent heat release: divergent circulations which project mostly into inertia-gravity waves react to changes in latent heat release in 1-2 days, its impact in subtropical latitudes is felt in 2-4 days; and becomes fully established after about 6 days. -from Authors