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@PHDTHESIS{Clemens:1021219,
      author       = {Clemens, Jan Heinrich},
      title        = {{M}ulti-scenario, high-resolution {L}agrangian transport
                      modeling for the analysis of the {A}sian tropopause aerosol
                      layer},
      volume       = {648},
      school       = {Bergische Universität Wuppertal},
      type         = {Dissertation},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2024-00660},
      isbn         = {978-3-95806-792-9},
      series       = {Reihe Energie $\&$ Umwelt / Energy $\&$ Environment},
      pages        = {143},
      year         = {2024},
      note         = {Dissertation, Bergische Universität Wuppertal, 2023},
      abstract     = {The Asian tropopause aerosol layer (ATAL) is a layer of
                      polluted air above Asia duringthe summer monsoon season,
                      which has a global and regional impact on climate. Thesource
                      regions that contribute to the formation of the ATAL are
                      still under discussion. Thisthesis investigates the source
                      regions and transport pathways of the ATAL in 2016
                      overNainital (India) with the help of a multi-scenario
                      Lagrangian backward transport analysisof balloon-borne
                      measurements using two Lagrangian transport models, the
                      MPTRACand the CLaMS, and the high-resolution ERA5 reanalysis
                      Transport from the planetary boundary layer to the ATAL is
                      characterized by fast ver-tical transport (e.g. by
                      convection) in the troposphere and subsequent slow diabatic
                      up-ward transport and large-scale horizontal transport in
                      the upper troposphere and lowerstratosphere. Therefore, in
                      this thesis, the Lagrangian transport model MPTRAC
                      wasequipped with diabatic transport calculations, which are
                      known to improve calculations inthe stratosphere. Due to the
                      high computational performance of MPTRAC, it allows
                      theemployment of a large number of scenarios with the ERA5
                      reanalysis. Vertical transportprocesses can be better
                      resolved by the high resolution of ERA5, and the large
                      numberof scenarios provides a comprehensive picture of
                      robust results and remaining uncer-tainties. MPTRAC also
                      contains parameterizations of convection and unresolved
                      winds.The transport scheme built into MPTRAC was evaluated
                      in detail by comparing it withthe transport scheme of CLaMS.
                      In this thesis, it is shown that MPTRAC and CLaMSwith ERA5
                      have negligible deviations from each other compared to
                      uncertainties suchas reanalysis uncertainties. Furthermore,
                      it is shown that diabatic transport calculationswith the
                      fully resolved ERA5 reanalysis cannot be replaced by
                      kinematic calculations orcalculations with a larger grid
                      width without significant differences, which corroborates
                      thetransition to optimized models with diabatic, fully
                      resolved calculations.The optimized models were used to
                      determine the source regions and transport path-ways that
                      influenced the measurements over Nainital. It was shown that
                      despite the large uncertainties related to vertical velocity
                      approaches, resolved and parameterized convec-tion, and
                      reanalyses, the largest air mass contribution originates
                      from the Indo-GangeticPlain, the Tibetan Plateau, and the
                      foothills of the Himalayas. However, the analysis alsoshowed
                      that uncertainties remain about the role of local,
                      unresolved convection over theIndo-Gangetic Plain and the
                      foothills of the Himalayas, as well as in relation to
                      convectionover China. The correlation between the
                      backscattering strength of the ATAL during themeasurement
                      campaign in August and the contributions from different
                      regions providesan indication as to what influence different
                      regions have on the ATAL. Using all scenar-ios, it was
                      robustly shown that increasing contributions from the
                      Tropical Western Pacific,which was under the influence of
                      tropical storms, correlate with a decrease in the mea-sured
                      backscatter. Wide but not complete agreement was found for
                      the Indo-GangeticPlain; larger contributions from this
                      region are positively correlated with the backscatter-ing of
                      the ATAL. In contrast to previous studies, no robust
                      correlation could be foundbetween the backscatter and the
                      contributions from the Tibetan Plateau, which showsthe
                      strength of the presented multi-scenario analysis, i.e., the
                      exposure of existing uncer-tainties. Overall, the analysis
                      emphasizes the role of anthropogenic source regions onthe
                      Indian subcontinent in the formation of the ATAL over
                      Nainital.},
      cin          = {IEK-7},
      cid          = {I:(DE-Juel1)IEK-7-20101013},
      pnm          = {2112 - Climate Feedbacks (POF4-211)},
      pid          = {G:(DE-HGF)POF4-2112},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      doi          = {10.34734/FZJ-2024-00660},
      url          = {https://juser.fz-juelich.de/record/1021219},
}