A simple model of the tropical atmosphere with circulation dependent heating and specific humidity.

Abstract

For equatorial sea temperature perturbations imposed on an idealized Pacific Ocean, the model shows two distinct modes of response. In one mode local evaporation is slightly more important than moisture convergence. This results in a relatively weak, equatorially trapped perturbation circulation. In the other mode moisture convergence is dominant and the associated circulation is stronger and less equatorially trapped. The necessary condition for the second 'enhanced' mode is that the positive sea temperature perturbations overlap sufficiently with the climatologically warm waters of the western ocean. Subtropical sea temperature perturbations generally result in a steady state heating with a relatively broad meridional scale and moderate magnitude. The final stages are relatively insensitive to the position of the sea temperature perturbations relative to the mean sea temperture field. -from Author