% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Jesswein:911910,
      author       = {Jesswein, Markus and Fernandez, Rafael P. and Berná, Lucas
                      and Saiz-Lopez, Alfonso and Grooß, Jens-Uwe and Hossaini,
                      Ryan and Apel, Eric C. and Hornbrook, Rebecca S. and Atlas,
                      Elliot L. and Blake, Donald R. and Montzka, Stephen and
                      Keber, Timo and Schuck, Tanja and Wagenhäuser, Thomas and
                      Engel, Andreas},
      title        = {{G}lobal seasonal distribution of {CH}2{B}r2 and {CHB}r3 in
                      the upper troposphere and lower stratosphere},
      journal      = {Atmospheric chemistry and physics},
      volume       = {22},
      number       = {22},
      issn         = {1680-7316},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2022-05157},
      pages        = {15049 - 15070},
      year         = {2022},
      abstract     = {Bromine released from the decomposition of short-lived
                      brominated source gases contributes as a sink of ozone in
                      the lower stratosphere. The two major contributors are
                      CH2Br2 and CHBr3. In this study, we investigate the global
                      seasonal distribution of these two substances, based on four
                      High Altitude and Long Range Research Aircraft (HALO)
                      missions, the HIAPER Pole-to-Pole Observations (HIPPO)
                      mission, and the Atmospheric Tomography (ATom) mission.
                      Observations of CH2Br2 in the free and upper troposphere
                      indicate a pronounced seasonality in both hemispheres, with
                      slightly larger mixing ratios in the Northern Hemisphere
                      (NH). Compared to CH2Br2, CHBr3 in these regions shows
                      larger variability and less clear seasonality, presenting
                      larger mixing ratios in winter and autumn in NH midlatitudes
                      to high latitudes. The lowermost stratosphere of SH and NH
                      shows a very similar distribution of CH2Br2 in hemispheric
                      spring with differences well below 0.1 ppt, while the
                      differences in hemispheric autumn are much larger with
                      substantially smaller values in the SH than in the NH. This
                      suggests that transport processes may be different in both
                      hemispheric autumn seasons, which implies that the influx of
                      tropospheric air (“flushing”) into the NH lowermost
                      stratosphere is more efficient than in the SH. The
                      observations of CHBr3 support the suggestion, with a steeper
                      vertical gradient in the upper troposphere and lower
                      stratosphere in SH autumn than in NH autumn. However, the SH
                      database is insufficient to quantify this difference. We
                      further compare the observations to model estimates of
                      TOMCAT (Toulouse Off-line Model of Chemistry And Transport)
                      and CAM-Chem (Community Atmosphere Model with Chemistry,
                      version 4), both using the same emission inventory of
                      Ordóñez et al. (2012). The pronounced tropospheric
                      seasonality of CH2Br2 in the SH is not reproduced by the
                      models, presumably due to erroneous seasonal emissions or
                      atmospheric photochemical decomposition efficiencies. In
                      contrast, model simulations of CHBr3 show a pronounced
                      seasonality in both hemispheres, which is not confirmed by
                      observations. The distributions of both species in the
                      lowermost stratosphere of the Northern and Southern
                      hemispheres are overall well captured by the models with the
                      exception of southern hemispheric autumn, where both models
                      present a bias that maximizes in the lowest 40 K above the
                      tropopause, with considerably lower mixing ratios in the
                      observations. Thus, both models reproduce equivalent
                      flushing in both hemispheres, which is not confirmed by the
                      limited available observations. Our study emphasizes the
                      need for more extensive observations in the SH to fully
                      understand the impact of CH2Br2 and CHBr3 on
                      lowermost-stratospheric ozone loss and to help constrain
                      emissions.},
      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:000890899200001},
      doi          = {10.5194/acp-22-15049-2022},
      url          = {https://juser.fz-juelich.de/record/911910},
}