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@ARTICLE{Petetin:858149,
      author       = {Petetin, Hervé and Sauvage, Bastien and Smit, Herman G. J.
                      and Gheusi, François and Lohou, Fabienne and Blot, Romain
                      and Clark, Hannah and Athier, Gilles and Boulanger, Damien
                      and Cousin, Jean-Marc and Nedelec, Philippe and Neis,
                      Patrick and Rohs, Susanne and Thouret, Valérie},
      title        = {{A} climatological view of the vertical stratification of
                      {RH}, {O}3 and {CO} within the {PBL} and at the interface
                      with free troposphere as seen by {IAGOS} aircraft and
                      ozonesondes at northern mid-latitudes over 1994–2016},
      journal      = {Atmospheric chemistry and physics},
      volume       = {18},
      number       = {13},
      issn         = {1680-7324},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2018-07056},
      pages        = {9561 - 9581},
      year         = {2018},
      abstract     = {This paper investigates in an innovative way the
                      climatological vertical stratification of relative humidity
                      (RH), ozone (O3) and carbon monoxide (CO) mixing ratios
                      within the planetary boundary layer (PBL) and at the
                      interface with the free troposphere (FT). The climatology
                      includes all vertical profiles available at northern
                      mid-latitudes over the period 1994–2016 in both the IAGOS
                      (In-service Aircraft for a Global Observing System) and
                      WOUDC (World Ozone and Ultraviolet Radiation Data Centre)
                      databases, which represents more than 90000 vertical
                      profiles. For all individual profiles, apart from the
                      specific case of surface-based temperature inversions
                      (SBIs), the PBL height is estimated following the elevated
                      temperature inversion (EI) method. Several features of both
                      SBIs and EIs are analysed, including their diurnal and
                      seasonal variations. Based on these PBL height estimates
                      (denoted h), the novel approach introduced in this paper
                      consists of building a so-called PBL-referenced vertical
                      distribution of O3, CO and RH by averaging all individual
                      profiles beforehand expressed as a function of z∕h rather
                      than z (with z the altitude). Using this vertical coordinate
                      system allows us to highlight the features existing at the
                      PBL–FT interface that would have been smoothed
                      otherwise.Results demonstrate that the frequently assumed
                      well-mixed PBL remains an exception for both chemical
                      species. Within the PBL, CO profiles are characterized by a
                      mean vertical stratification (here defined as the standard
                      deviation of the CO profile between the surface and the PBL
                      top, normalized by the mean) of $11\%,$ with moderate
                      seasonal and diurnal variations. A higher vertical
                      stratification is observed for O3 mixing ratios $(18\%),$
                      with stronger seasonal and diurnal variability (from
                      $∼ 10\%$ in spring–summer midday–afternoon to
                      $∼ 25\%$ in winter–fall night). This vertical
                      stratification is distributed heterogeneously in the PBL
                      with stronger vertical gradients observed at both the
                      surface (due to dry deposition and titration by NO for O3
                      and due to surface emissions for CO) and the PBL–FT
                      interface. These gradients vary with the season from the
                      lowest values in summer to the highest ones in winter. In
                      contrast to CO, the O3 vertical stratification was found to
                      vary with the surface potential temperature following an
                      interesting bell shape with the weakest stratification for
                      both the lowest (typically negative) and highest
                      temperatures, which could be due to much lower O3 dry
                      deposition in the presence of snow.Therefore, results
                      demonstrate that EIs act as a geophysical interface
                      separating air masses of distinct chemical composition
                      and/or chemical regime. This is further supported by the
                      analysis of the correlation of O3 and CO mixing ratios
                      between the different altitude levels in the PBL and FT (the
                      so-called vertical autocorrelation). Results indeed
                      highlight lower correlations apart from the PBL–FT
                      interface and higher correlations within each of the two
                      atmospheric compartments (PBL and FT).},
      cin          = {IEK-8},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IEK-8-20101013},
      pnm          = {243 - Tropospheric trace substances and their
                      transformation processes (POF3-243)},
      pid          = {G:(DE-HGF)POF3-243},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000437733900007},
      doi          = {10.5194/acp-18-9561-2018},
      url          = {https://juser.fz-juelich.de/record/858149},
}