% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{vonHobe:878776,
      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 / Discussions},
      volume       = {891},
      issn         = {1680-7367},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2020-03038},
      pages        = {},
      year         = {2020},
      abstract     = {Abstract. Every year during the Asian summer monsoon season
                      from about mid-June to early September, a stable
                      anticyclonic circulation system forms over the Himalayans.
                      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 time scales 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 80–100 ppb CO and 30–50 ppb O3 at
                      about 365 K potential temperature. CO mixing ratios reach
                      stratospheric background values of ~ 20 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 326 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 0.3–0.8 K day−1. For gases not subject to
                      microphysical processes, neither the lapse rate tropopause
                      (LRT) around 380 K nor the cold point tropopause (CPT)
                      around 390 K marks the strong discontinuity of the key
                      tracers (CO, O3, and N2O). Up to about 10 to 20 K above the
                      CPT, isolation of air inside the ASM anticyclone prevents
                      significant in-mixing of stratospheric air. 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          = {244 - Composition and dynamics of the upper troposphere and
                      middle atmosphere (POF3-244)},
      pid          = {G:(DE-HGF)POF3-244},
      typ          = {PUB:(DE-HGF)16},
      doi          = {10.5194/acp-2020-891},
      url          = {https://juser.fz-juelich.de/record/878776},
}