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@ARTICLE{Aghedo:9339,
      author       = {Aghedo, A.M. and Rast, S. and Schultz, M. G.},
      title        = {{S}ensitivity of tracer transport to model resolution,
                      prescribed meteorology and tracer lifetime in the general
                      circulation model {ECHAM}5},
      journal      = {Atmospheric chemistry and physics},
      volume       = {10},
      issn         = {1680-7316},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {PreJuSER-9339},
      pages        = {3385 - 3396},
      year         = {2010},
      note         = {This work was carried out during the doctoral work of AMA,
                      sponsored by the ZEIT foundation through the International
                      Max Planck Research School on Earth System Modelling
                      (IMPRS-ESM). SR and MGS acknowledge funding from the EU
                      project RETRO (EVK2-CT-2002-00170). We are grateful to the
                      ECMWF for providing the reanalysis data, and to Erich
                      Roeckner, Marco Giorgetta, and Kevin W Bowman for their
                      useful comments, and also to Luis Kornblueh for the
                      technical assistance. The model runs were performed on the
                      Sun Computing system (YANG) at the Max Planck Institute for
                      Meteorology, Hamburg and the NEC SX-6 computer at the German
                      Climate Computing Centre ("Deutsches Klimarechenzentrum").
                      We thank the editor, Peter Haynes, and appreciate the
                      comments of Kenneth Bowman, and three other anonymous
                      referees, which have significantly improve the manuscript.},
      abstract     = {Atmospheric transport of traces gases and aerosols plays an
                      important role in the distribution of air pollutants and
                      radiatively active compounds. For model simulations of
                      chemistry-climate interactions it is important to know how
                      the transport of tracers depends on the geographical
                      resolution of the general circulation model. However, this
                      aspect has been scarcely investigated until now. Here, we
                      analyse tracer transport in the ECHAM5 general circulation
                      model using 6 independent idealized tracers with constant
                      lifetimes, which are released in two different altitudes at
                      the surface and in the stratosphere, respectively. Model
                      resolutions from T21L19 to T106L31 were tested by performing
                      multi-annual simulations with prescribed sea surface
                      temperatures and sea ice fields of the 1990s. The impacts of
                      the tracer lifetime were investigated by varying the
                      globally uniform exponential decay time between 0.5 and 50
                      months. We also tested the influence of using prescribed
                      meteorological fields (ERA40) instead of climatological sea
                      surface temperature and sea ice fields. Meridional transport
                      of surface tracers decreases in the coarse resolution model
                      due to enhanced vertical mixing, with the exception of the
                      advection into the tropical region, which shows an
                      inconsistent trend between the resolutions. Whereas, the
                      meridional transport of tracers released in the stratosphere
                      was enhanced with higher model resolutions, except in the
                      transport from tropical stratosphere to the Southern
                      Hemisphere, which exhibits an increase trend with increasing
                      model resolution. The idealized tracers exhibit a seasonal
                      cycle, which is modulated by the tracer lifetime. In
                      comparison to the run with prescribed sea surface
                      temperature and sea ice fields, the simulation with
                      prescribed meteorological fields did not exhibit significant
                      change in the meridional transport, except in the exchange
                      of stratospheric tracers between both hemispheres, where it
                      causes about $100\%$ increase. The import of the surface
                      tracers into the stratosphere is increased by up to a factor
                      of 2.5, and the export from the stratosphere into the
                      troposphere was increased by up to $60\%$ when prescribed
                      meteorological fields is used. The ERA40 simulation also
                      showed larger interannual variability (up to $24\%$ compared
                      to $12\%$ in the standard simulations). Using our surface
                      tracers released in either the northern or Southern
                      Hemisphere, respectively, we calculate inter-hemispheric
                      transport times between 11 and 17 months, consistent with
                      values reported in the literature. While this study cannot
                      be used to relate differences in model results to specific
                      changes in transport processes, it nevertheless provides
                      some insight into the characteristics of tracer transport in
                      the widely used ECHAM5 general circulation model.},
      keywords     = {J (WoSType)},
      cin          = {ICG-2},
      ddc          = {550},
      cid          = {I:(DE-Juel1)VDB791},
      pnm          = {Atmosphäre und Klima},
      pid          = {G:(DE-Juel1)FUEK406},
      shelfmark    = {Meteorology $\&$ Atmospheric Sciences},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000276663600017},
      url          = {https://juser.fz-juelich.de/record/9339},
}