% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Reutter:891838,
      author       = {Reutter, Philipp and Neis, Patrick and Rohs, Susanne and
                      Sauvage, Bastien},
      title        = {{I}ce supersaturated regions: properties and validation of
                      {ERA}-{I}nterim reanalysis with {IAGOS} in situ water vapour
                      measurements},
      journal      = {Atmospheric chemistry and physics},
      volume       = {20},
      number       = {2},
      issn         = {1680-7324},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {FZJ-2021-01761},
      pages        = {787 - 804},
      year         = {2020},
      abstract     = {Cirrus clouds and their potential formation regions,
                      so-called ice supersaturated regions (ISSRs), with values of
                      relative humidity with respect to ice exceeding $100 \%,$
                      occur frequently in the tropopause region. It is assumed
                      that ISSRs and cirrus clouds can change the tropopause
                      structure by diabatic processes, driven by latent heating
                      due to phase transition and interaction with radiation. For
                      many research questions, a three-dimensional picture
                      including a sufficient temporal resolution of the water
                      vapour fields in the tropopause region is required. This
                      requirement is fulfilled nowadays by reanalysis products
                      such as the European Centre for Medium-Range Weather
                      Forecasts (ECMWF) ERA-Interim reanalysis. However, for a
                      meaningful investigation of water vapour in the tropopause
                      region, a comparison of the reanalysis data with measurement
                      is advisable, since it is difficult to measure water vapour
                      and to assimilate meaningful measurements into reanalysis
                      products. Here, we present an intercomparison of
                      high-resolution in situ measurements aboard passenger
                      aircraft within the European Research Infrastructure IAGOS
                      (In-service Aircraft for a Global Observing System;
                      http://www.iagos.org, last access: 15 January 2020) with
                      ERA-Interim. Temperature and humidity data over the North
                      Atlantic from 2000 to 2009 are compared relative to the
                      dynamical tropopause. The comparison of the temperature
                      shows good agreement between the measurement and
                      ERA-Interim. While ERA-Interim also shows the main features
                      of the water vapour measurements of IAGOS, the variability
                      of the data is clearly smaller in the reanalysis data set.
                      The combination of temperature and water vapour leads to the
                      relative humidity with respect to ice (RHi). Here,
                      ERA-Interim deviates from the measurements concerning values
                      larger than $RHi=100 \%,$ both in number and strength of
                      supersaturation. Also, pathlengths of ISSRs along flight
                      tracks are investigated, representing macrophysical
                      properties as linked to atmospheric flows. The comparison of
                      ISSR pathlengths shows distinct differences, which can be
                      traced back to the spatial resolution of both data sets.
                      Also, the seasonal cycle and height dependence of
                      pathlengths changes for the different data sets due to their
                      spatial resolution. IAGOS shows a significantly greater
                      amount of smaller ISSRs compared to ERA-Interim. Good
                      agreement begins only at pathlengths on the order of the
                      ERA-Interim spatial resolution and larger.},
      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:000509386500001},
      doi          = {10.5194/acp-20-787-2020},
      url          = {https://juser.fz-juelich.de/record/891838},
}