The Effects of Gravity waves and Convection on the Tropical Tropopause Region in a Microphysical Model

Clouds and water vapor in the tropical tropopause region (TTR) are important for both stratospheric water vapor and the tropical radiative balance. The interaction of clouds and water vapor in this region are complex because the time scales for different processes are similar. For example, up to the tropopause, the slow upward transfer due to radiative heating is comparable in importance to convective mixing. What this means is that water vapor removal processes associated with cirrus clouds formed in situ by horizontal motion through large scale cold regions are comparable to hydration due to convection. In addition, gravity waves of multiple time scales have a significant impact on the formation of cirrus clouds and subsequent water vapor removal. Finally, because the region is near saturation, microphysical processes must be treated in detail to obtain a complete picture. Previous work has examined the TTR with a trajectory-based microphysical model that includes either gravity waves or convection, but not both. This paper will examine the effects of both convection and gravity waves on the the water vapor and cloud distributions in the TTR.