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@ARTICLE{Rotermund:901873,
      author       = {Rotermund, Meike K. and Bense, Vera and Chipperfield,
                      Martyn P. and Engel, Andreas and Grooß, Jens-Uwe and Hoor,
                      Peter and Hüneke, Tilman and Keber, Timo and Kluge, Flora
                      and Schreiner, Benjamin and Schuck, Tanja and Vogel, Bärbel
                      and Zahn, Andreas and Pfeilsticker, Klaus},
      title        = {{O}rganic and inorganic bromine measurements around the
                      extratropical tropopause and lowermost stratosphere:
                      insights into the transport pathways and total bromine},
      journal      = {Atmospheric chemistry and physics},
      volume       = {21},
      number       = {20},
      issn         = {1680-7324},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2021-03881},
      pages        = {15375 - 15407},
      year         = {2021},
      abstract     = {We report on measurements of total bromine (Brtot) in the
                      upper troposphere and lower stratosphere taken during 15
                      flights with the German High Altitude and LOng range
                      research aircraft (HALO). The research campaign WISE
                      (Wave-driven ISentropic Exchange) included regions over the
                      North Atlantic, Norwegian Sea, and northwestern Europe in
                      fall 2017. Brtot is calculated from measured total organic
                      bromine (Brorg) added to inorganic bromine (Brinorgy),
                      evaluated from measured BrO and photochemical modeling.
                      Combining these data, the weighted mean [Brtot] is
                      19.2±1.2 ppt in the northern hemispheric lower
                      stratosphere (LS), in agreement with expectations for Brtot
                      in the middle stratosphere (Engel and Rigby et al., 2018).
                      The data reflect the expected variability in Brtot in the LS
                      due to variable influx of shorter lived brominated source
                      and product gases from different regions of entry. A closer
                      look into Brorg and Brinorgy, as well as simultaneously
                      measured transport tracers (CO and N2O) and an air mass lag
                      time tracer (SF6), suggests that bromine-rich air masses
                      persistently protruded into the lowermost stratosphere (LMS)
                      in boreal summer, creating a high bromine region (HBrR). A
                      subsection, HBrR∗, has a weighted average of
                      [Brtot] = 20.9±0.8 ppt. The most probable source
                      region is air recently transported from the tropical upper
                      troposphere and tropopause layer (UT/TTL) with a weighted
                      mean of [Brtot] = 21.6±0.7 ppt. CLaMS Lagrangian
                      transport modeling shows that the HBrR air mass consists of
                      $51.2 \%$ from the tropical troposphere, $27.1 \%$ from
                      the stratospheric background, and $6.4 \%$ from the
                      midlatitude troposphere (as well as contributions from other
                      domains). The majority of the surface air reaching the HBrR
                      is from the Asian monsoon and its adjacent tropical regions,
                      which greatly influences trace gas transport into the LMS in
                      boreal summer and fall. Tropical cyclones from Central
                      America in addition to air associated with the Asian monsoon
                      region contribute to the elevated Brtot observed in the
                      UT/TTL. TOMCAT global 3-D model simulations of a concurrent
                      increase of Brtot show an associated O3 change of
                      $−2.6±0.7 \%$ in the LS and $−3.1±0.7 \%$ near the
                      tropopause. Our study of varying Brtot in the LS also
                      emphasizes the need for more extensive monitoring of
                      stratospheric Brtot globally and seasonally to fully
                      understand its impact on LMS O3 and its radiative forcing of
                      climate, as well as in aged air in the middle stratosphere
                      to elucidate the stratospheric trend in bromine.},
      cin          = {IEK-7},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IEK-7-20101013},
      pnm          = {2112 - Climate Feedbacks (POF4-211)},
      pid          = {G:(DE-HGF)POF4-2112},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000709139700001},
      doi          = {10.5194/acp-21-15375-2021},
      url          = {https://juser.fz-juelich.de/record/901873},
}