A general circulation model study of the impact of a stratospheric sudden warming event on tropical convection

Abstract

The impact of a Northern Hemisphere stratospheric sudden warming (SSW) event on tropical convection is investigated as an initial value problem using a general circulation model. The amplification of planetary waves that produced the simulated SSW was forced by introducing an anomalous field in the model initial conditions. The impact of this SSW event on the tropics was examined by comparing runs with and without the SSW. An increased stratospheric mean meridional circulation cools the tropical lower stratosphere when planetary waves propagate upward into the stratosphere, leading to enhanced convective activity in the equatorial Southern Hemisphere. This result is consistent with previous observational studies, and indicates that convective activity in the equatorial region is influenced by SSW events.