An Examination of ACCLIP (2022) Airborne Observations in the Context of their Trajectory-derived Convective Influence

<p>The Asian summer monsoon (ASM) has long been known as a weather system, but only recently has its role in atmospheric composition come to be explored in detail.&#160; During boreal summer, an anticyclone forms in the upper troposphere and lower stratosphere (UTLS) over Asia which is associated with a pronounced enhancement of chemical and aerosol species lofted from the boundary layer (BL) by ASM deep convection.&#160; In this work, we explore the transport pathways and time scales associated with ASM anticyclone shedding events, which effectively redistribute air from the anticyclone into the global atmosphere.&#160; In particular, we launch a series of kinematic backward trajectories using ERA5 reanalysis from the western Pacific UTLS, emphasizing a novel set of airborne in situ observations taken during the summer 2022 Asian summer monsoon Chemical and Climate Impact Project (ACCLIP).&#160; Trajectories are integrated backward in time to their most recent encounters with a satellite-derived database of convective cloud top altitudes, as well as the top of the BL.&#160; We find that there is a consistent story between observed pollution concentrations and their associated trajectory-derived transport histories, with enhanced concentrations of BL pollutants preferentially found in air masses with shorter transport times from their convective or BL sources.&#160; We also find that air mass contributions from eastern Asia preferentially contain higher pollutant concentrations compared to those from southern Asia.&#160; The results provide valuable context for the measurements taken during ACCLIP and provide new insight into the role of ASM transport in global atmospheric composition.&#160;&#160;&#160;</p>