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@PHDTHESIS{Hanumanthu:903809,
      author       = {Hanumanthu, Sreeharsha},
      title        = {{T}rajectory {A}nalysis on the {A}sian {T}ropopause
                      {A}erosol {L}ayer ({ATAL}) based on {B}alloon {M}easurements
                      at the {F}oothills of the {H}imalayas},
      volume       = {552},
      school       = {Universität Wuppertal},
      type         = {Dissertation},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2021-05442},
      isbn         = {978-3-95806-578-9},
      series       = {Schriften des Forschungszentrums Jülich. Reihe Energie
                      $\&$ Umwelt / Energy $\&$ Environment},
      pages        = {xiv, 147 S.},
      year         = {2021},
      note         = {Universität Wuppertal, Diss., 2021},
      abstract     = {The South Asian summer monsoon is associated with a
                      large-scale anticyclonic circulation in the Upper
                      Troposphere and Lower Stratosphere, which confines the air
                      mass inside. During boreal summer, the confinement of this
                      air mass leads to an accumulation of aerosol between about
                      13 km and 18 km (360 K and 440 K potential temperature),
                      this accumulation of aerosol constitutes the Asian
                      Tropopause Aerosol Layer (ATAL). In this thesis
                      balloon-borne aerosol back-scatter measurements of the ATAL
                      are presented by the Compact Optical Backscatter Aerosol
                      Detector (COBALD) instrument in Nainital in Northern India
                      in August 2016, and in the post-monsoon time in November
                      2016. The presence of an ATAL is then detected by the
                      enhancement of the August measurements compared to the
                      November measurements. The measurements demonstrate a strong
                      variability of the ATAL’s altitude, vertical extent,
                      aerosol backscatter intensity and cirrus cloud occurrence
                      frequency. Such a variability cannot be deduced from
                      climatological means of the ATAL as they are derived from
                      satellite measurements. To explain this observed variability
                      a Lagrangian back-trajectory analysis was performed using
                      the Chemical Lagrangian Model of the Stratosphere(CLaMS). We
                      identify the transport pathways of air parcels contributing
                      to the ATAL over Nainital in August 2016, as well as the
                      source regions of the air masses contributingto the
                      composition of the ATAL. The analysis reveals a variety of
                      factors contributing to the observed day-to-day variability
                      of the ATAL: continental convection, tropical cyclones
                      (maritime convection), dynamics of the anticyclone and
                      stratospheric intrusions. Thus, the ATAL is a mixture of air
                      masses coming from different atmospheric height layers. In
                      addition, contributions from the model boundary layer
                      originate in different geographic source regions. The
                      location of strongest updraft along the backward
                      trajectories reveal a cluster of strong upward transport at
                      the southern edge of the Himalayan foothills. From the top
                      of the convective outflow level (about 13 km; 360 K) the air
                      parcels ascend slowly to ATAL altitudes within a large-scale
                      upward spiral driven by the diabatic heating in the
                      anticyclonic flow ofthe South Asian summer monsoon at UTLS
                      altitudes. [...]},
      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},
      url          = {https://juser.fz-juelich.de/record/903809},
}