Chemistry of hydrogen oxide radicals (HOx) in the Arctic troposphere in spring

• DOI: 10.5194/acp-10-5823-2010
• Publication Date: 2010-07-01T09:04:11Z
• Authors: J. Mao; D. J. Jacob; M. J. Evans; J. R. Olson; X. Ren; W. H. Brune; J. M. St. Clair; J. D. Crounse; K. M. Spencer; M. R. Beaver; P. O. Wennberg; M. J. Cubison; J. L. Jimenez; A. Fried; P. Weibring; J. G. Walega; S. R. Hall; A. J. Weinheimer; R. C. Cohen; G. Chen; J. H. Crawford; C. McNaughton; A. D. Clarke; L. Jaeglé; J. A. Fisher; R. M. Yantosca; P. Le Sager; C. Carouge
• Keywords: Scavenging; Sink (geography)

Abstract. We use observations from the April 2008 NASA ARCTAS aircraft campaign to North American Arctic, interpreted with a global 3-D chemical transport model (GEOS-Chem), better understand sources and cycling of hydrogen oxide radicals (HOx≡H+OH+peroxy radicals) their reservoirs (HOy≡HOx+peroxides) in springtime Arctic atmosphere. find that standard gas-phase mechanism overestimates observed HO2 H2O2 concentrations. Computation HOx HOy budgets on basis also indicates large missing sink for both. hypothesize this could reflect uptake by aerosols, favored low temperatures relatively high aerosol loadings, through does not produce H2O2. implemented such an using reactive coefficient parameterization γ(HO2) values ranging 0.02 at 275 K 0.5 220 K. This successfully reproduces concentrations vertical distributions different species reservoirs. is then major sink, decreasing mean OH troposphere 32% 31% respectively. Better rate product data are needed role aerosols limiting oxidizing power