Impact of temperature-driven cycling of hydrogen peroxide (H2O2) between air and snow on the planetary boundary layer

• Main Authors: Hutterli, M. A., McConnell, J. R., Stewart, R. W., Jacobi, Hans-Werner, Bales, R. C.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2001
• Subjects: Greenland; ice core
• Online Access: https://epic.awi.de/id/eprint/4468/; https://epic.awi.de/id/eprint/4468/1/Hut2001a.pdf; https://hdl.handle.net/10013/epic.15043; https://hdl.handle.net/10013/epic.15043.d001

Hydrogen peroxide (H2O2) contributes to the atmospheres oxidizing capacity, which determinesthe lifetime of atmospheric trace species. Measured bidirectional summertime H2O2 fluxes fromthe snowpack at Summit, Greenland, in June 1996 reveal a daytime H2O2 release from thesurface snow reservoir and a partial redeposition at night. The observations also provide the firstdirect evidence of a strong net summertime H2O2 release from the snowpack, enhancing averageboundary layer H2O2 concentrations approximately sevenfold and the OH and HO2concentrations by 70% and 50%, respectively, relative to that estimated from photochemicalmodeling in the absence of the snowpack source. The total H2O2 release over a 12-day periodwas of the order of 5 * 10(13) molecules m(-2) s(-1) and compares well with observed concentrationchanges in the top snow layer. Photochemical and air-snow interaction modeling indicate thatthe net snowpack release is driven by temperature-induced uptake and release of H2O2 asdeposited snow, which is supersaturated with respect to ice-air partitioning, approachesequilibrium. The results show that the physical cycling of H2O2 and possibly other volatilespecies is a key to understanding snowpacks as complex physical-photochemical reactors and hasfar reaching implications for the interpretation of ice core records as well as for thephotochemistry in polar regions and in the vicinity of snowpacks in general.