Impact of temperature-driven cycling of hydrogen peroxide between the air and snow on the planetary boundary layer


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hwjacobi [ at ] awi-bremerhaven.de

Abstract

H2O2 is an important component of the atmospheric oxidizingcapacity, determining the lifetime of atmospheric tracespecies. Bi-directional summertime H2O2 fluxes from thesnowpack at Summit, Greenland, reveal a daytime release fromthe surface snow reservoir during the warm part of the dayand a partial re-deposition at night. The data also providethe first direct evidence of a strong net summertime H2O2release from the snowpack, increasing average boundary layerH2O2 concentrations ~ 7-fold and the OH and HO2concentrations by 70% and 50%, respectively. Changes in H2O2concentration in the snow combined with photochemical andair-snow interaction modeling show that the net snowpackrelease is driven by temperature induced desorption of H2O2as deposited snow, which is supersaturated with respect toice-air partitioning, approaches equilibrium. The resultsshow that the physical cycling of H2O2, and possibly othervolatile species is a key to understanding snowpacks ascomplex physical-photochemical reactors and has far reachingimplications for the interpretation of ice core records aswell as for the photochemistry in polar regions and in thevicinity of snowpacks in general.



Item Type
Conference (Talk)
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Not peer-reviewed
Publication Status
Published
Event Details
AGU Fall Meeting, 15-19 Dec., San Francisco, USA.
Eprint ID
4473
Cite as
Hutterli, M. A. , Bales, R. C. , McConnell, J. R. , Stewart, R. W. and Jacobi, H. W. (2000): Impact of temperature-driven cycling of hydrogen peroxide between the air and snow on the planetary boundary layer , AGU Fall Meeting, 15-19 Dec., San Francisco, USA .


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