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

Journal Article


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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≡H+OH+peroxy radicals) and their reservoirs (HOy≡HOx+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 γ(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.

UOW Authors


  •   Mao, Jingqiu (external author)
  •   Jacob, Daniel J. (external author)
  •   Evans, M J. (external author)
  •   Olson, J R. (external author)
  •   Ren, X (external author)
  •   Brune, W H. (external author)
  •   St. Clair, T M. (external author)
  •   Crounse, John D. (external author)
  •   Spencer, K M. (external author)
  •   Beaver, M R. (external author)
  •   Wennberg, Paul O. (external author)
  •   Cubison, Michael J. (external author)
  •   Jimenez, Jose L. (external author)
  •   Fried, Alan (external author)
  •   Weibring, P (external author)
  •   Walega, J G. (external author)
  •   Hall, Samuel R. (external author)
  •   Weinheimer, A J. (external author)
  •   Cohen, Ronald C. (external author)
  •   Chen, Gao (external author)
  •   Crawford, J H. (external author)
  •   Mcnaughton, C (external author)
  •   Clarke, A D. (external author)
  •   Jaeglé, L (external author)
  •   Fisher, Jenny
  •   Yantosca, Robert M. (external author)
  •   Le Sager, P (external author)
  •   Carouge, Claire C. (external author)

Publication Date


  • 2010

Citation


  • Mao, J., Jacob, D. J., Evans, M. J., Olson, J. R., Ren, X., Brune, W. H., St. Clair, T. 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. C. (2010). Chemistry of hydrogen oxide radicals (HOx) in the Arctic troposphere in spring. Atmospheric Chemistry and Physics, 10 (13), 5823-5838.

Scopus Eid


  • 2-s2.0-77953645744

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=8035&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/4692

Number Of Pages


  • 15

Start Page


  • 5823

End Page


  • 5838

Volume


  • 10

Issue


  • 13

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≡H+OH+peroxy radicals) and their reservoirs (HOy≡HOx+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 γ(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.

UOW Authors


  •   Mao, Jingqiu (external author)
  •   Jacob, Daniel J. (external author)
  •   Evans, M J. (external author)
  •   Olson, J R. (external author)
  •   Ren, X (external author)
  •   Brune, W H. (external author)
  •   St. Clair, T M. (external author)
  •   Crounse, John D. (external author)
  •   Spencer, K M. (external author)
  •   Beaver, M R. (external author)
  •   Wennberg, Paul O. (external author)
  •   Cubison, Michael J. (external author)
  •   Jimenez, Jose L. (external author)
  •   Fried, Alan (external author)
  •   Weibring, P (external author)
  •   Walega, J G. (external author)
  •   Hall, Samuel R. (external author)
  •   Weinheimer, A J. (external author)
  •   Cohen, Ronald C. (external author)
  •   Chen, Gao (external author)
  •   Crawford, J H. (external author)
  •   Mcnaughton, C (external author)
  •   Clarke, A D. (external author)
  •   Jaeglé, L (external author)
  •   Fisher, Jenny
  •   Yantosca, Robert M. (external author)
  •   Le Sager, P (external author)
  •   Carouge, Claire C. (external author)

Publication Date


  • 2010

Citation


  • Mao, J., Jacob, D. J., Evans, M. J., Olson, J. R., Ren, X., Brune, W. H., St. Clair, T. 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. C. (2010). Chemistry of hydrogen oxide radicals (HOx) in the Arctic troposphere in spring. Atmospheric Chemistry and Physics, 10 (13), 5823-5838.

Scopus Eid


  • 2-s2.0-77953645744

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=8035&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/4692

Number Of Pages


  • 15

Start Page


  • 5823

End Page


  • 5838

Volume


  • 10

Issue


  • 13