Convection over the Pacific Warm Pool in relation to the Atmospheric Kelvin-Rossby Wave*

Abstract

Deep convection over the western tropical Pacific warm pool is analyzed in terms of its relation to the atmospheric Kelvin-Rossby wave, which dominates the large-scale flow during the austral summer. The study uses Doppler radar data collected by aircraft and ship radars during different time periods in the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment to characterize the mesoscale circulations of organized convective cloud systems occurring throughout the season. The study focuses on convection in two contrasting phases of the wave: the ''westerly onset region'' just west of the point within the wave where low-level easterlies change to westerlies, and the ''strong westerly region'' (or ''westerly wind burst'') lying between the large-scale counterrotating gyres of the Kelvin-Rossby wave.