Ozone Atmosphere-Snowpack Gas Exchange Processes in Polar and Midlatitude Snowpacks

Photochemical processes have been shown to drive the surface-atmosphere gas exchange of photochemically important tropospheric trace gases. This research investigates ozone-snowpack gas exchange processes and the chemical, physical and meteorological parameters that determine ozone fluxes. Research has been conducted over year-round snowpack at Summit, Greenland, and at South Pole, Antarctica. Furthermore, two seasonally snow-covered sites in the Rocky Mountains, Colorado have been investigated. Experiments include flux measurements by the tower gradient and by eddy correlation methods and measurements of ozone in interstitial air at several depths in the snowpack. These data illustrate that ozone deposition to snow depends on multiple parameters, the most important ones including snow chemical composition, snow depth and incoming solar radiation. These dependencies warrant consideration in atmospheric chemistry and transport models for accurate descriptions of the tropospheric ozone budget in the Polar Regions.