Model Simulation of the Convectively Lofted Ice Contribution to Stratospheric Water Vapor

Stratospheric water vapor is an important greenhouse gas, which also plays an essential role in stratospheric chemistry. The evaporation of convectively lofted ice is an important process that can contribute to stratospheric water vapor. Here we conduct several experiments using a trajectory model driven by two chemistry-climate models (CCMs) to study the contribution of lofted ice to tropical lower-stratospheric water vapor. In our experiment, we divide the tropical tropopause layer into several isentropic layers, and find out that the horizontal distribution of lofted ice evaporation and its net contribution are similar on each layer. We also find out that lofted ice from the layer right above the tropopause makes greatest contribution. In addition, a final dehydration location perspective explanation is provided to explain this.