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@ARTICLE{Ungermann:889039,
      author       = {Ungermann, Jörn and Bartolome, Irene and Griessbach,
                      Sabine and Spang, Reinhold and Rolf, Christian and Krämer,
                      Martina and Höpfner, Michael and Riese, Martin},
      title        = {{C}irrus cloud shape detection by tomographic extinction
                      retrievals from infrared limb emission sounder measurements},
      journal      = {Atmospheric measurement techniques},
      volume       = {13},
      number       = {12},
      issn         = {1867-8548},
      address      = {Katlenburg-Lindau},
      publisher    = {Copernicus},
      reportid     = {FZJ-2020-05409},
      pages        = {7025 - 7045},
      year         = {2020},
      abstract     = {We investigate the impact of model trace gas transport
                      schemes on the representation of transport processes in the
                      upper troposphere and lower stratosphere. Towards this end,
                      the Chemical Lagrangian Model of the Stratosphere (CLaMS)
                      was coupled to the ECHAM/MESSy Atmospheric Chemistry (EMAC)
                      model and results from the two transport schemes (Lagrangian
                      critical Lyapunov scheme and flux-form semi-Lagrangian,
                      respectively) were compared. Advection in CLaMS was driven
                      by the EMAC simulation winds, and thereby the only
                      differences in transport between the two sets of results
                      were caused by differences in the transport schemes. To
                      analyze the timescales of large-scale transport, multiple
                      tropical-surface-emitted tracer pulses were performed to
                      calculate age of air spectra, while smaller-scale transport
                      was analyzed via idealized, radioactively decaying tracers
                      emitted in smaller regions (nine grid cells) within the
                      stratosphere. The results show that stratospheric transport
                      barriers are significantly stronger for Lagrangian
                      EMAC-CLaMS transport due to reduced numerical diffusion. In
                      particular, stronger tracer gradients emerge around the
                      polar vortex, at the subtropical jets, and at the edge of
                      the tropical pipe. Inside the polar vortex, the more
                      diffusive EMAC flux-form semi-Lagrangian transport scheme
                      results in a substantially higher amount of air with ages
                      from 0 to 2 years (up to a factor of 5 higher). In the
                      lowermost stratosphere, mean age of air is much smaller in
                      EMAC, owing to stronger diffusive cross-tropopause
                      transport. Conversely, EMAC-CLaMS shows a summertime
                      lowermost stratosphere age inversion – a layer of older
                      air residing below younger air (an “eave”). This pattern
                      is caused by strong poleward transport above the subtropical
                      jet and is entirely blurred by diffusive cross-tropopause
                      transport in EMAC. Potential consequences from the choice of
                      the transport scheme on chemistry–climate and
                      geoengineering simulations are discussed.},
      cin          = {IEK-7 / JSC / JARA-HPC},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IEK-7-20101013 / I:(DE-Juel1)JSC-20090406 /
                      $I:(DE-82)080012_20140620$},
      pnm          = {244 - Composition and dynamics of the upper troposphere and
                      middle atmosphere (POF3-244) / 511 - Computational Science
                      and Mathematical Methods (POF3-511) / Tomographic retrievals
                      of temperature and trace gasses from GLORIA measurements
                      $(jiek72_20200501)$},
      pid          = {G:(DE-HGF)POF3-244 / G:(DE-HGF)POF3-511 /
                      $G:(DE-Juel1)jiek72_20200501$},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000602537700005},
      doi          = {10.5194/amt-13-7025-2020},
      url          = {https://juser.fz-juelich.de/record/889039},
}