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@ARTICLE{vonHobe:890964,
      author       = {von Hobe, Marc and Ploeger, Felix and Konopka, Paul and
                      Kloss, Corinna and Ulanowski, Alexey and Yushkov, Vladimir
                      and Ravegnani, Fabrizio and Volk, C. Michael and Pan, Laura
                      L. and Honomichl, Shawn B. and Tilmes, Simone and Kinnison,
                      Douglas E. and Garcia, Rolando R. and Wright, Jonathon S.},
      title        = {{U}pward transport into and within the {A}sian monsoon
                      anticyclone as inferred from {S}trato{C}lim trace gas
                      observations},
      journal      = {Atmospheric chemistry and physics},
      volume       = {21},
      number       = {2},
      issn         = {1680-7324},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2021-01280},
      pages        = {1267 - 1285},
      year         = {2021},
      abstract     = {Every year during the Asian summer monsoon season from
                      about mid-June to early September, a stable anticyclonic
                      circulation system forms over the Himalayas. This Asian
                      summer monsoon (ASM) anticyclone has been shown to promote
                      transport of air into the stratosphere from the Asian
                      troposphere, which contains large amounts of anthropogenic
                      pollutants. Essential details of Asian monsoon transport,
                      such as the exact timescales of vertical transport, the role
                      of convection in cross-tropopause exchange, and the main
                      location and level of export from the confined anticyclone
                      to the stratosphere are still not fully resolved. Recent
                      airborne observations from campaigns near the ASM
                      anticyclone edge and centre in 2016 and 2017, respectively,
                      show a steady decrease in carbon monoxide (CO) and increase
                      in ozone (O3) with height starting from tropospheric values
                      of around 100 ppb CO and 30–50 ppb O3 at about 365 K
                      potential temperature. CO mixing ratios reach stratospheric
                      background values below ∼25 ppb at about 420 K and do
                      not show a significant vertical gradient at higher levels,
                      while ozone continues to increase throughout the altitude
                      range of the aircraft measurements. Nitrous oxide (N2O)
                      remains at or only marginally below its 2017 tropospheric
                      mixing ratio of 333 ppb up to about 400 K, which is
                      above the local tropopause. A decline in N2O mixing ratios
                      that indicates a significant contribution of stratospheric
                      air is only visible above this level. Based on our
                      observations, we draw the following picture of vertical
                      transport and confinement in the ASM anticyclone: rapid
                      convective uplift transports air to near 16 km in
                      altitude, corresponding to potential temperatures up to
                      about 370 K. Although this main convective outflow layer
                      extends above the level of zero radiative heating (LZRH),
                      our observations of CO concentration show little to no
                      evidence of convection actually penetrating the tropopause.
                      Rather, further ascent occurs more slowly, consistent with
                      isentropic vertical velocities of 0.7–1.5 K d−1. For
                      the key tracers (CO, O3, and N2O) in our study, none of
                      which are subject to microphysical processes, neither the
                      lapse rate tropopause (LRT) around 380 K nor the cold
                      point tropopause (CPT) around 390 K marks a strong
                      discontinuity in their profiles. Up to about 20 to 35 K
                      above the LRT, isolation of air inside the ASM anticyclone
                      prevents significant in-mixing of stratospheric air
                      (throughout this text, the term in-mixing refers
                      specifically to mixing processes that introduce
                      stratospheric air into the predominantly tropospheric inner
                      anticyclone). The observed changes in CO and O3 likely
                      result from in situ chemical processing. Above about
                      420 K, mixing processes become more significant and the
                      air inside the anticyclone is exported vertically and
                      horizontally into the surrounding stratosphere.},
      cin          = {IEK-7},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IEK-7-20101013},
      pnm          = {211 - Die Atmosphäre im globalen Wandel (POF4-211) /
                      STRATOCLIM - Stratospheric and upper tropospheric processes
                      for better climate predictions (603557) / DFG project
                      392169209 - Klimavariabilität in der oberen Troposphäre
                      und Stratosphäre über Asien und ihre Darstellung in
                      modernen Re-Analysen},
      pid          = {G:(DE-HGF)POF4-211 / G:(EU-Grant)603557 /
                      G:(GEPRIS)392169209},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000614287500003},
      doi          = {10.5194/acp-21-1267-2021},
      url          = {https://juser.fz-juelich.de/record/890964},
}