Results from a comparison of HCN measurements and Lagrangian backtrajectory analyses in the Asian Summer Monsoon Anticyclone

The StratoClim aircraft field campaign took place from Kathmandu, Nepal, in summer 2017 inorder to study the atmospheric composition, chemistry, and dynamics in the Asian SummerMonsoon Anticyclone (ASMA) which is known to transport surface emissions to the mid-latitudelower stratosphere and the stratosphere worldwide. Hydrogen cyanide (HCN) which is primarilyemitted from biomass burning and has a UTLS lifetime on the order of 1-2 years is a good tracer forbiomass burning import into the lower and free stratosphere.HCN in the ASM Upper Troposphere and Lower Stratosphere (UTLS) was measured in-situemploying the Chemical-Ionization Time-of-Flight Mass Spectrometer FUNMASS on board thehigh-altitude research aircraft M55-Geophysica. The observed HCN mixing ratios in and above theASMA exhibit interesting vertical and horizontal signatures around the tropopause as well as in theLS probably resulting from convective activity or air mass origin (AMO). We here comparemeasured HCN to Lagrangian simulations by the ClaMS and TRACZILLA models which employtwo different approaches to represent higher-reaching convective events. The simulations succeed totrack some of the observed HCN features back to convective activity or AMO. The quality of thereproduction and further outcomes on the atmospheric relevance will be discussed in thepresentation.