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@ARTICLE{Schumann:825094,
      author       = {Schumann, Ulrich and Kiemle, Christoph and Schlager, Hans
                      and Weigel, Ralf and Borrmann, Stephan and D'amato, F. and
                      Krämer, Martina and Matthey, Renaud and Protat, Alain and
                      Voigt, Christiane and Volk, Michael},
      title        = {{L}ong-lived contrails and convective cirrus above the
                      tropical tropopause},
      journal      = {Atmospheric chemistry and physics / Discussions},
      volume       = {},
      issn         = {1680-7375},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2016-07571},
      pages        = {},
      year         = {2016},
      abstract     = {Contrails of the Russian high-flying research aircraft M-55
                      "Geophysica" are investigated in measurements above the
                      tropical tropopause during the SCOUT-O3 field-experiment
                      near Darwin, Australia, in 2005. The aircraft reached
                      19 km altitude, far above the tropopause with −87 °C
                      temperature at 17 km. In-situ, lidar, and
                      microwave-temperature profiler measurements on board the
                      Geophysica are used. An upward-looking lidar on the German
                      research aircraft "Falcon", the CPOL radar near Darwin, and
                      NOAA-AVHRR satellites provide complementary data. Exhaust
                      emission indices are derived from a self-match experiment of
                      the Geophysica in the polar stratosphere in 2010. Plume
                      positions are estimated based on measured or analyzed wind
                      and parameterized wake vortex descent. One contrail is
                      detectable in a photo, and characterized in-situ during
                      contrail formation downwind of the overshooting convective
                      system "Hector" of 16 November 2005. The upper part of the
                      contrail formed in the tropical lower stratosphere at
                      $~ 60 \%$ relative humidity over ice at −82 °C. The
                      ~ 1-h lifetime is explained by engine water emissions,
                      slightly enhanced humidity from Hector, low temperature, low
                      turbulence, and possibly nitric-acid hydrate formation. The
                      long persistence suggests large contrail coverage from
                      future high-flying aircraft. Further Geophysica contrail
                      parts are found in the measurements inside the strongly
                      convective Hector clouds on 30 November 2005. Most of the
                      non-volatile aerosol measured over Hector is traceable to
                      aircraft emissions. Cirrus clouds observed by lidar above
                      the anvil occur in coincidence with computed contrail
                      positions. The upper part of the stratospheric anvil can be
                      explained as contrail cirrus in this case. The radar
                      indicates that the cirrus was measured in-situ mostly
                      besides and above overshooting convection, and the maximum
                      ice water content in the overshoots is far higher than
                      measured along the flight path. The evidence suggests that
                      parts of the ice clouds measured are contrails or mixtures
                      of convective and contrail cirrus. The number of ice
                      particles in the contrails is less than $1 \%$ of the
                      number of non-volatile aerosol particles, possibly because
                      of sublimation losses and undetected very small ice
                      particles. The findings are of relevance with respect to
                      hydration of the lower stratosphere, overshooting
                      convection, and future increases of air traffic in the lower
                      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-2016-940},
      url          = {https://juser.fz-juelich.de/record/825094},
}