This study aims to better understand the mechanism of transport of water vapour through the mid-latitude tropopause. The results affirm the strong influence of overshooting convection on lower-stratospheric water vapour and highlight the importance of both dynamics and cloud microphysics in simulating water vapour distribution in the region of the upper troposphere–lower stratosphere.

This study focuses on the hydration patch that was measured during the StratoClim field campaign and the corresponding convective overshoots over the Sichuan Basin. Through analysis using airborne and spaceborne measurements and the numerical simulation using a non-hydrostatic model, we show the key hydration process and pathway of the hydration patch in tropical tropopause layer.

We present Lagrangian simulations of polar stratospheric clouds (PSCs) for the Arctic winter 2009/2010 and the Antarctic winter 2011 using the Chemical Lagrangian Model of the Stratosphere (CLaMS). The paper comprises a detailed model description with ice PSCs and related dehydration being the focus of this study. Comparisons between our simulations and observations from different satellites on season-long and vortex-wide scales as well as for single PSC events show an overall good agreement.

The deep convection in tropics can inject cloud ice into tropical tropopause layer (TTL), which moistens and increases water vapor there. We primarily study the spatial distribution of impacts from several physical processes on TTL water vapor from observations and trajectory model simulations. The analysis shows the potential moistening impact from evaporation of cloud ice on TTL water vapor. A chemistry–climate model is used to confirm the impact from evaporation of convective ice.