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@ARTICLE{Weigel:185591,
      author       = {Weigel, R. and Volk, C. M. and Kandler, K. and Hösen, E.
                      and Günther, G. and Vogel, B. and Grooß, J.-U. and
                      Khaykin, S. and Belyaev, G. V. and Borrmann, S.},
      title        = {{E}nhancements of the refractory submicron aerosol fraction
                      in the {A}rctic polar vortex: feature or exception?},
      journal      = {Atmospheric chemistry and physics},
      volume       = {14},
      number       = {22},
      issn         = {1680-7324},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2014-07017},
      pages        = {12319 - 12342},
      year         = {2014},
      abstract     = {In situ measurements with a four-channel stratospheric
                      condensation particle counter (CPC) were conducted at up to
                      20 km altitude on board the aircraft M-55 Geophysica from
                      Kiruna, Sweden, in January through March (EUPLEX 2003,
                      RECONCILE 2010) and in December (ESSenCe 2011). During all
                      campaigns air masses from the upper stratosphere and
                      mesosphere were subsiding inside the Arctic winter vortex,
                      thus initializing a transport of refractory aerosol into the
                      lower stratosphere (Θ < 500 K). The strength and extent of
                      this downward transport varied between the years depending
                      on the dynamical evolution of the vortex. Inside the vortex
                      and at potential temperatures Θ ≥ 450 K around 11
                      submicron particles per cm3 were generally detected. Up to 8
                      of these 11 particles per cm3 were found to contain
                      thermo-stable (at 250 °C) residuals with diameters of 10 nm
                      to about 1 μm. Particle mixing ratios (150 mg−1) and
                      fractions of non-volatile particles $(75\%$ of totally
                      detected particles) exhibited highest values in air masses
                      having the lowest content of nitrous oxide (70 nmol mol−1
                      of N2O). This indicates that refractory aerosol originates
                      from the upper stratosphere or the mesosphere. Derived from
                      the mixing ratio of the simultaneously measured long-lived
                      tracer N2O, an empirical index serves to differentiate
                      probed air masses according to their origin: inside the
                      vortex, the vortex edge region, or outside the vortex.
                      Previously observed high fractions of refractory submicron
                      aerosol in the 2003 Arctic vortex were ascribed to unusually
                      strong subsidence during that winter. However, measurements
                      under perturbed vortex conditions in 2010 and during early
                      winter in December 2011 revealed similarly high values.
                      Thus, the abundance of refractory aerosol in the lower
                      stratosphere within the Arctic vortices appears to be a
                      regular feature rather than the exception. During December,
                      the import from aloft into the lower stratosphere appears to
                      be developing; thereafter the abundance of refractory
                      aerosol inside the vortex reaches its highest levels in
                      March. The correlations of refractory aerosol with N2O
                      suggest that, apart from mean subsidence, diabatic
                      dispersion inside the vortex significantly contributes to
                      the transport of particles to the Arctic lower stratosphere.
                      A measurement-based estimate of the total mass of refractory
                      aerosol inside the vortex is provided for each campaign.
                      Based on the derived increase of particle mass in the lower
                      stratospheric vortex (100–67 hPa pressure altitude) by a
                      factor of 4.5 between early and late winter, we estimate the
                      total mass of mesospheric particles deposited over the
                      winter 2009/2010 in the entire Arctic vortex to range
                      between 77 × 103 and 375 × 106 kg. This estimate is
                      compared with the expected atmospheric influx of meteoritic
                      material (110 ± 55 × 103 kg per day). Such estimates at
                      present still hold considerable uncertainties, which are
                      discussed in this article. Nevertheless, the results enable
                      placing constraints on the shape of the so far unknown size
                      distribution of refractory aerosol within the vortex.},
      cin          = {IEK-7},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IEK-7-20101013},
      pnm          = {234 - Composition and Dynamics of the Upper Troposphere and
                      Stratosphere (POF2-234)},
      pid          = {G:(DE-HGF)POF2-234},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000345290700021},
      doi          = {10.5194/acp-14-12319-2014},
      url          = {https://juser.fz-juelich.de/record/185591},
}