Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 5.509 IF 5.509
  • IF 5-year value: 5.689 IF 5-year 5.689
  • CiteScore value: 5.44 CiteScore 5.44
  • SNIP value: 1.519 SNIP 1.519
  • SJR value: 3.032 SJR 3.032
  • IPP value: 5.37 IPP 5.37
  • h5-index value: 86 h5-index 86
  • Scimago H index value: 161 Scimago H index 161
Volume 14, issue 22
Atmos. Chem. Phys., 14, 12373-12392, 2014
https://doi.org/10.5194/acp-14-12373-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: Oxidant Production over Antarctic Land and its Export...

Atmos. Chem. Phys., 14, 12373-12392, 2014
https://doi.org/10.5194/acp-14-12373-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 26 Nov 2014

Research article | 26 Nov 2014

Measurements of OH and RO2 radicals at Dome C, East Antarctica

A. Kukui1,4, M. Legrand2, S. Preunkert2, M. M. Frey3, R. Loisil5, J. Gil Roca1, B. Jourdain2, M. D. King6, J. L. France6, and G. Ancellet1 A. Kukui et al.
  • 1Laboratoire Atmosphère, Milieux et Observations Spatiales (LATMOS), UMR8190, CNRS-Université de Versailles Saint Quentin, Université Pierre et Marie Curie, Paris, France
  • 2Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), UMR5183, CNRS-Université Grenoble Alpes, Grenoble, France
  • 3British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Cambridge, UK
  • 4Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), UMR6115, CNRS–Université d'Orléans, 45071 Orléans CEDEX 2, France
  • 5Division Technique (UPS855) de l'Institut National des Sciences de l'Univers (INSU), Meudon, France
  • 6Department of Earth Sciences, Royal Holloway University of London, Egham, Surrey, TW20 OEX, UK

Abstract. Concentrations of OH radicals and the sum of peroxy radicals, RO2, were measured in the boundary layer for the first time on the East Antarctic Plateau at the Concordia Station (Dome C, 75.10° S, 123.31° E) during the austral summer 2011/2012. The median concentrations of OH and RO2 radicals were 3.1 × 106 molecule cm−3 and 9.9 × 106 molecule cm−3, respectively. These values are comparable to those observed at the South Pole, confirming that the elevated oxidative capacity of the Antarctic atmospheric boundary layer found at the South Pole is not restricted to the South Pole but common over the high Antarctic plateau. At Concordia, the concentration of radicals showed distinct diurnal profiles with the median maximum of 5.2 × 106 molecule cm−3 at 11:00 and the median minimum of 1.1 × 106 molecule cm−3 at 01:00 for OH radicals and 1.7 × 108 molecule cm−3 and 2.5 × 107 molecule cm−3 for RO2 radicals at 13:00 and 23:00, respectively (all times are local times). Concurrent measurements of O3, HONO, NO, NO2, HCHO and H2O2 demonstrated that the major primary source of OH and RO2 radicals at Dome C was the photolysis of HONO, HCHO and H2O2, with the photolysis of HONO contributing ~75% of total primary radical production. However, photochemical modelling with accounting for all these radical sources overestimates the concentrations of OH and RO2 radicals by a factor of 2 compared to field observations. Neglecting the net OH production from HONO in the photochemical modelling results in an underestimation of the concentrations of OH and RO2 radicals by a factor of 2. To explain the observations of radicals in this case an additional source of OH equivalent to about (25–35)% of measured photolysis of HONO is required. Even with a factor of 5 reduction in the concentrations of HONO, the photolysis of HONO represents the major primary radical source at Dome C. To account for a possibility of an overestimation of NO2 observed at Dome C the calculations were also performed with NO2 concentrations estimated by assuming steady-state NO2 / NO ratios. In this case the net radical production from the photolysis of HONO should be reduced by a factor of 5 or completely removed based on the photochemical budget of OH or 0-D modelling, respectively. Another major factor leading to the large concentration of OH radicals measured at Dome C was large concentrations of NO molecules and fast recycling of peroxy radicals to OH radicals.

Publications Copernicus
Special issue
Download
Short summary
Concentrations of OH radicals and the sum of peroxy radicals, RO2, were measured in the boundary layer for the first time on the East Antarctic Plateau at the Concordia Station during the austral summer 2011/2012. The concentrations of radicals were comparable to those observed at the South Pole, confirming that the elevated oxidative capacity of the Antarctic atmospheric boundary layer found at the South Pole is not restricted to the South Pole but common over the high Antarctic plateau.
Concentrations of OH radicals and the sum of peroxy radicals, RO2, were measured in the boundary...
Citation
Share