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@ARTICLE{Hooghiem:888070,
      author       = {Hooghiem, Joram J. D. and Popa, Maria Elena and Röckmann,
                      Thomas and Grooß, Jens-Uwe and Tritscher, Ines and Müller,
                      Rolf and Kivi, Rigel and Chen, Huilin},
      title        = {{W}ildfire smoke in the lower stratosphere identified by in
                      situ {CO} observations},
      journal      = {Atmospheric chemistry and physics},
      volume       = {20},
      number       = {22},
      issn         = {1680-7324},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2020-04648},
      pages        = {13985 - 14003},
      year         = {2020},
      abstract     = {Wildfires emit large quantities of aerosols and trace
                      gases, which occasionally reach the lower stratosphere. In
                      August 2017, several pyro-cumulonimbus events injected a
                      large amount of smoke into the stratosphere, observed by
                      lidar and satellites. Satellite observations are in general
                      the main method of detecting these events since in situ
                      aircraft- or balloon-based measurements of atmospheric
                      composition at higher altitudes are not made frequently
                      enough. This work presents accidental balloon-borne trace
                      gas observations of wildfire smoke in the lower
                      stratosphere, identified by enhanced CO mole fractions at
                      approximately 13.6 km. In addition to CO mole fractions,
                      CO2 mole fractions and isotopic composition of CO (δ13C and
                      δ18O) have been measured in air samples, from both the
                      wildfire plume and background, collected using an AirCore
                      and a lightweight stratospheric air sampler (LISA) flown on
                      a weather balloon from Sodankylä (4–7 September 2017;
                      67.37∘ N, 26.63∘ E; 179 m a.m.s.l.), Finland.
                      The greenhouse gas enhancement ratio (ΔCO:ΔCO2) and the
                      isotopic signature based on δ13C(CO) and δ18O(CO)
                      independently identify wildfire emissions as the source of
                      the stratospheric CO enhancement. Back-trajectory analysis
                      was performed with the Chemical Lagrangian Model of the
                      Stratosphere (CLaMS), tracing the smoke's origin to
                      wildfires in British Columbia with an injection date of 12
                      August 2017. The trajectories are corrected for vertical
                      displacement due to heating of the wildfire aerosols, by
                      observations made by the Cloud-Aerosol Lidar with Orthogonal
                      Polarization (CALIOP) instrument. Knowledge of the age of
                      the smoke allowed for a correction of the enhancement ratio,
                      ΔCO:ΔCO2, for the chemical removal of CO by OH. The stable
                      isotope observations were used to estimate the amount of
                      tropospheric air in the plume at the time of observation to
                      be about $45±21 \%.$ Finally, the plume extended over
                      1 km in altitude, as inferred from the observations.},
      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:000590431000003},
      doi          = {10.5194/acp-20-13985-2020},
      url          = {https://juser.fz-juelich.de/record/888070},
}