Dehydration and low ozone in the tropopause layer over the Asian monsoon caused by tropical cyclones: Lagrangian transport calculations using ERA-Interim and ERA5 reanalysis data

Low ozone and high water vapour mixing ratios are common features in the Asian summer monsoon (ASM) anticyclone; however, low ozone and low water vapour values were observed near the tropopause over Kunming, China, within the ASM using balloon-borne measurements performed during the SWOP (sounding water vapour, ozone, and particle) campaign in August 2009 and 2015. Here, we investigate low ozone and water vapour signatures in the upper troposphere and lower stratosphere (UTLS) using FengYun-2D, FengYun-2G, and Aura Microwave Limb Sounder (MLS) satellite measurements and backward trajectory calculations.

Trajectories with kinematic and diabatic vertical velocities were calculated using the Chemical Lagrangian Model of the Stratosphere (CLaMS) trajectory module driven by both ERA-Interim and ERAS reanalysis data.