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@ARTICLE{Kunz:9731,
      author       = {Kunz, A. and Konopka, P. and Müller, R. and Pan, L.L.},
      title        = {{D}ynamical tropopause based on isentropic {PV} gradients},
      journal      = {Journal of Geophysical Research},
      volume       = {116},
      issn         = {0148-0227},
      address      = {Washington, DC},
      publisher    = {Union},
      reportid     = {PreJuSER-9731},
      year         = {2011},
      note         = {This work is supported in part by EOS, a program of the
                      Helmholtz Association of German Research Centres, and by the
                      German Academy of Sciences Leopoldina (support code LPDS
                      2009-25). Thanks go to Heini Wernli and two anonymous
                      reviewers for their constructive criticisms. We further
                      thank Thomas Birner, Leigh Munchak, Jeffrey Taylor, and Juan
                      Antonio Anel for their helpful comments on an earlier
                      version of the manuscript.},
      abstract     = {Since its inception, the dynamical tropopause based on
                      potential vorticity (PV) is identified by the PV gradient on
                      isentropes. Conceptually, significant isentropic gradients
                      shown on the middle world PV maps reflect the underlying
                      transport barrier associated with the tropopause, formed by
                      jet streams that separate tropospheric air masses at low
                      latitudes and stratospheric air masses at high latitudes.
                      Largely owing to the lack of a general method, the dynamical
                      tropopause has often been represented by a PV value chosen
                      ad hoc without any temporal or spatial differentiation. In
                      this work, we present a method for determining the PV
                      isoline of the dynamical tropopause based on the isentropic
                      PV gradients. Using 1 year of data from the European Centre
                      for Medium-Range Weather Forecasts, the spatial and temporal
                      variability of this PV gradient-based dynamical tropopause
                      is examined. The results show that in general there is a
                      broad distribution of PV values at the dynamical tropopause,
                      ranging from 1.5 to 5 potential vorticity units. Therefore,
                      a fixed PV surface for all isentropes and seasons does not
                      accurately represent the location of the "tropopause
                      barrier." The PV at the dynamical tropopause increases with
                      increasing potential temperature. This increase is more
                      pronounced in the Southern Hemisphere than in the Northern
                      Hemisphere. The seasonal cycle shows higher PV values at the
                      dynamical tropopause during summer than during winter. This
                      seasonal cycle is larger on higher isentropes. The
                      dispersion of the PV at the dynamical tropopause about its
                      mean is twofold larger during summer and autumn than during
                      winter and spring in both hemispheres.},
      keywords     = {J (WoSType)},
      cin          = {IEK-7},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IEK-7-20101013},
      pnm          = {Atmosphäre und Klima},
      pid          = {G:(DE-Juel1)FUEK491},
      shelfmark    = {Meteorology $\&$ Atmospheric Sciences},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000286325000001},
      doi          = {10.1029/2010JD014343},
      url          = {https://juser.fz-juelich.de/record/9731},
}