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@ARTICLE{Khaykin:823843,
      author       = {Khaykin, Sergey M. and Pommereau, Jean-Pierre and Riviere,
                      Emmanuel D. and Held, Gerhard and Ploeger, Felix and
                      Ghysels, Melanie and Amarouche, Nadir and Vernier, Jean-Paul
                      and Wienhold, Frank G. and Ionov, Dmitry},
      title        = {{E}vidence of horizontal and vertical transport of water in
                      the {S}outhern {H}emisphere tropical tropopause layer
                      ({TTL}) from high-resolution balloon observations},
      journal      = {Atmospheric chemistry and physics},
      volume       = {16},
      number       = {18},
      issn         = {1680-7324},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2016-06483},
      pages        = {12273 - 12286},
      year         = {2016},
      abstract     = {High-resolution in situ balloon measurements of water
                      vapour, aerosol, methane and temperature in the upper
                      tropical tropopause layer (TTL) and lower stratosphere are
                      used to evaluate the processes affecting the stratospheric
                      water budget: horizontal transport (in-mixing) and hydration
                      by cross-tropopause overshooting updrafts. The obtained in
                      situ evidence of these phenomena are analysed using
                      satellite observations by Aura MLS (Microwave Limb Sounder)
                      and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder
                      Satellite Observation) together with trajectory and
                      transport modelling performed using CLaMS (Chemical
                      Lagrangian Model of the Stratosphere) and HYSPLIT (Hybrid
                      Single-Particle Lagrangian Integrated Trajectory)
                      model.Balloon soundings were conducted during March 2012 in
                      Bauru, Brazil (22.3° S) in the frame of the TRO-Pico
                      campaign for studying the impact of convective overshooting
                      on the stratospheric water budget. The balloon payloads
                      included two stratospheric hygrometers: FLASH-B
                      (Fluorescence Lyman-Alpha Stratospheric Hygrometer for
                      Balloon) and Pico-SDLA instrument as well as COBALD (Compact
                      Optical Backscatter Aerosol Detector) sondes, complemented
                      by Vaisala RS92 radiosondes. Water vapour vertical profiles
                      obtained independently by the two stratospheric hygrometers
                      are in excellent agreement, ensuring credibility of the
                      vertical structures observed.A signature of in-mixing is
                      inferred from a series of vertical profiles, showing
                      coincident enhancements in water vapour (of up to
                      0.5 ppmv) and aerosol at the 425 K (18.5 km) level.
                      Trajectory analysis unambiguously links these features to
                      intrusions from the Southern Hemisphere extratropical
                      stratosphere, containing more water and aerosol, as
                      demonstrated by MLS and CALIPSO global observations. The
                      in-mixing is successfully reproduced by CLaMS simulations,
                      showing a relatively moist filament extending to 20° S. A
                      signature of local cross-tropopause transport of water is
                      observed in a particular sounding, performed on a convective
                      day and revealing water vapour enhancements of up to
                      0.6 ppmv as high as the 404 K (17.8 km) level. These
                      are shown to originate from convective overshoots upwind
                      detected by an S-band weather radar operating locally in
                      Bauru.The accurate in situ observations uncover two
                      independent moisture pathways into the tropical lower
                      stratosphere, which are hardly detectable by space-borne
                      sounders. We argue that the moistening by horizontal
                      transport is limited by the weak meridional gradients of
                      water, whereas the fast convective cross-tropopause
                      transport, largely missed by global models, can have a
                      substantial effect, at least at a regional scale.},
      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},
      UT           = {WOS:000385396900004},
      doi          = {10.5194/acp-16-12273-2016},
      url          = {https://juser.fz-juelich.de/record/823843},
}