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@ARTICLE{Berresheim:29243,
      author       = {Berresheim, H. and Plass-Dülmer, C. and Elste, T. and
                      Mihalopoulos, N. and Rohrer, F.},
      title        = {{OH} in the coastal boundary layer of {C}rete during
                      {MINOS} : measurements and relationship with ozone
                      photolysis},
      journal      = {Atmospheric chemistry and physics},
      volume       = {3},
      issn         = {1680-7316},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {PreJuSER-29243},
      pages        = {639 - 649},
      year         = {2003},
      note         = {Record converted from VDB: 12.11.2012},
      abstract     = {Hydroxyl radical (OH) concentrations were measured in
                      August 2001 at Finokalia Station on the northeastern coast
                      of Crete during the Mediterranean Intensive Oxidant Study
                      (MINOS). OH was measured based on selected ion chemical
                      ionization mass spectrometry (SI/CIMS) with a time
                      resolution of 30 sec and signal integration of 5 min. The
                      corresponding accuracy, precision, and detection limit were
                      $20\%$ (1sigma), $11\%$ (1sigma), and 2.4 x 10(5) molecules
                      cm(-3) (2sigma), respectively. OH levels showed a strong
                      diurnal variability with high maxima (approximately 2 x
                      10(7) molecules cm(-3)) occurring around 13:30 LT (10:30
                      UTC) and nighttime values below the detection limit. Daily
                      24-hour average concentrations varied between 3.6-6.7 x
                      10(6) cm(-3). For the total measurement period (6-21 August)
                      the mean and standard deviation were 4.5 +/- 1.1 x 10(6)
                      cm(-3). The OH data set is analyzed based on a
                      classification into three periods: I: Aug 6-8, II: Aug 9-11,
                      III: Aug 13-18. For each of the three periods the measured
                      OH concentrations are described by the empirical function
                      [OH] = a J((OD)-D-1)(b), with J((OD)-D-1) being the ozone
                      photolysis frequency and a = 1.4 x 10(10) s cm(-3), 1.7 x
                      10(10) s cm(-3), 2.2 x 10(10) s cm(-3), and b = 0.68,
                      respectively. Taking into account the estimated precision of
                      the OH measurements this empirical function using three
                      values for a and one value for b explains $99\%$ of the
                      observed variance of OH. A detailed sensitivity analysis
                      using a CH4-CO box model was performed to interpret this
                      relationship, in particular the meanings of the
                      pre-exponential factor a and the exponent b. It was found
                      that the value of b which represents the total logarithmic
                      dependence of [OH] on J((OD)-D-1) includes the individual
                      contributions from the photolysis of O-3, NO2, HCHO, HONO,
                      and H2O2 which could be determined using the box model. For
                      the conditions prevailing during the MINOS campaign the
                      exponent b was found to be dominated by the contributions
                      from O-3- and NO2-photolysis. For the in-dividual functional
                      dependences between [OH] and J((OD)-D-1), [OH] and J(NO2),
                      and J(NO2) and J((OD)-D-1) the partial logarithmic
                      derivatives were determined to be 0.5, 0.6, and 0.3,
                      respectively. Overall, the box model yields a value of 0.70
                      for the exponent b in very good agreement with the
                      corresponding value derived from the empirical analysis of
                      the measurements. This empirical approach in which the
                      chemical air mass characteristics influencing the OH radical
                      balance and thereby, the self-cleansing efficiency of the
                      atmosphere, are represented by only two parameters which are
                      constant over quite substantial time periods may be used in
                      future experiments to test and compare OH measurements made
                      in different atmospheric environments.},
      keywords     = {J (WoSType)},
      cin          = {ICG-II},
      ddc          = {550},
      cid          = {I:(DE-Juel1)VDB48},
      pnm          = {Chemie und Dynamik der Geo-Biosphäre},
      pid          = {G:(DE-Juel1)FUEK257},
      shelfmark    = {Meteorology $\&$ Atmospheric Sciences},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000183456700004},
      doi          = {10.5194/acp-3-639-2003},
      url          = {https://juser.fz-juelich.de/record/29243},
}