气候变化领域集成服务门户

All trajectory calculations show that air parcels with low ozone and low water vapour values in the UTLS over Kunming measured by balloon-borne instruments originate from the western Pacific boundary layer. Deep convection associated with tropical cyclones over the western Pacific transports ozone-poor air from the marine boundary layer to the cold tropopause region. Subsequently, these air parcels are mixed into the strong easterlies on the southern side of the Asian summer monsoon anticyclone. Air parcels are dehydrated when passing the lowest temperature region (< 190 K) at the convective outflow of tropical cyclones. However, trajectory calculations show different vertical transport via deep convection depending on the employed reanalysis data (ERA-Interim, ERA5) and vertical velocities (diabatic, kinematic). Both the kinematic and the diabatic trajectory calculations using ERA5 data show much faster and stronger vertical transport than ERA-Interim primarily because of ERA5's better spatial and temporal resolution, which likely resolves convective events more accurately. Our findings show that the interplay between the ASM anticyclone and tropical cyclones has a significant impact on the chemical composition of the UTLS during summer. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License.