Speakers
Dr
Didier Voisin
(CNRS, Glaciology Laboratory)Dr
Florent Domine
(CNRS, Glaciology Laboratory)
Description
Aldehydes are key reactive species produced by photochemical processes in the snow. They have the potential to be released to the atmosphere, affecting its oxidative capacity. We have performed measurements of formaldehyde, acetaldehyde, glyoxal and methylglyoxal in polar snow, and in particular at Barrow, Alaska, where atmospheric mixing ratios of formaldehyde were also measured. The predominant aldehyde is formaldehyde, HCHO. Based on recent laboratory studies of HCHO diffusion and solubility in ice, we demonstrate that HCHO forms a solid solution with ice and that the variations of its concentrations in snow can be explained by solid state diffusion in and out of snow grains. Events are observed where HCHO concentrations in snow increase, while HCHO is also emitted by snow, demonstrating a photochemical source of HCHO in the snow. Acetaldehyde, glyoxal and methylglyoxal concentrations are correlated to those of formaldehyde. However, the lack of basic data on the interactions of those species with ice, and the absence of measurement of their atmospheric mixing ratios prevents a detailed quantitative interpretation of their concentrations. Together, these three species can be as abundant as formaldehyde, so that their role can be important and warrant further studies.
Please list some keywords
aldehydes, formaldehyde, air-snow exchange, solid solution, diffusion in ice, snow photochemistry
Author
Dr
Florent Domine
(CNRS, Glaciology Laboratory)
Co-authors
Dr
Alan Fried
(National Center for Atmospheric Research)
Dr
Didier Voisin
(CNRS, Glaciology Laboratory)
Dr
Dirk Richter
(National Center for Atmospheric Research)
Dr
James Walega
(National Center for Atmospheric Research)
Dr
Jean-Charles Gallet
(CNRS, Glaciology Laboratory)
Mr
Manuel Barret
(CNRS, Glaciology Laboratory)
Dr
Petter Weibring
(National Center for Atmospheric Research)
Stephan Houdier
(CNRS, Glaciology Laboratory)
