Title Chemistry of hydrogen oxide radicals (HOx) in the Arctic troposphere in spring
Author Mao, J.; Jacob, D.J.; Evans, M.J.; Olson, J.R.; Ren, X.; Brune, W.H.; St.Clair, J.M.; Crounse, J.D.; Spencer, K.M.; Beaver, M.R.; Wennberg, P.O.; Cubison, M.J.; Jimenez, J.L.; Fried, A.; Weibring, P.; Walega, J.G.; Hall, S.R.; Weinheimer, A.J.; Cohen, R.C.; Chen, G.; Crawford, J.H.; McNaughton, C.; Clarke, A.D.; Jaeglé, L.; Fisher, J.A.; Yantosca, R.M.; Le Sager, P.; Carouge, C.
Author Affil Mao, J., Harvard University, School of Engineering and Applied Sciences, Cambridge, MA. Other: University of Leeds, United Kingdom; NASA, Langley Research Center; Rosenstiel School of Marine and Atmospheric Science; Pennsylvania State University; California Institute of Technology; University of Colorado at Boulder; National Center for Atmospheric Research; University of California Berkeley; University of Hawaii at Manoa; University of Washington
Source Atmospheric Chemistry and Physics, 10(13), p.5823-5838, . Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1680- 7316
Publication Date 2010
Notes In English. Part of special issue no. 182, POLARCAT (Polar study using aircraft, remote sensing, surface measurements and models, of climate, chemistry, aerosols, and transport), edited by Stohl, A., et al., http://www.atmos-chem- phys.net/special_issue182.html; Published in Atmospheric Chemistry and Physics Discussions: 11 March 2010, http://www.atmos- chem-phys-discuss.net/10/6955/2010/acpd-10- 6955-2010.html ; accessed in June, 2011. 114 refs. GeoRef Acc. No: 310040
Index Terms aerosols; aerial surveys; biomass; fires; geochemistry; global change; global warming; ozone; pollution; simulation; temperature; ultraviolet radiation; Arctic region; airborne methods; Arctic Research of the Composition of the Troposphere from Aircraft and Satellites; atmosphere; atmospheric transport; climate forcing; electromagnetic radiation; gaseous phase; GEOS-Chem; hydrogen oxide; hydrogen peroxide; hydroperoxyl; oxidation; pH; photochemistry; pollutants; seasonal variations; sinks; solar forcing; three-dimensional models; transport; troposphere
Abstract We use observations from the April 2008 NASA ARCTAS aircraft campaign to the North American Arctic, interpreted with a global 3-D chemical transport model (GEOS- Chem), to better understand the sources and cycling of hydrogen oxide radicals (HOx#IWH+OH+peroxy radicals) and their reservoirs (HOy#IWHOx+peroxides) in the springtime Arctic atmosphere. We find that a standard gas-phase chemical mechanism overestimates the observed HO2 and H2O2 concentrations. Computation of HOx and HOy gas-phase chemical budgets on the basis of the aircraft observations also indicates a large missing sink for both. We hypothesize that this could reflect HO2 uptake by aerosols, favored by low temperatures and relatively high aerosol loadings, through a mechanism that does not produce H2O2. We implemented such an uptake of HO2 by aerosol in the model using a standard reactive uptake coefficient parameterization with gamma (HO2) values ranging from 0.02 at 275 K to 0.5 at 220 K. This successfully reproduces the concentrations and vertical distributions of the different HOx species and HOy reservoirs. HO2 uptake by aerosol is then a major HOx and HOy sink, decreasing mean OH and HO2 concentrations in the Arctic troposphere by 32% and 31% respectively. Better rate and product data for HO2 uptake by aerosol are needed to understand this role of aerosols in limiting the oxidizing power of the Arctic atmosphere.
URL http://www.atmos-chem-phys.net/10/5823/2010/acp-10-5823-2010.pdf
Publication Type journal article
Record ID 65006812