In recent decades, the Arctic has witnessed startling environmental changes prompting concerns about the Arctic climate system, which in turn, could amplify climate change on a global scale. In recent years, studies have provided evidence that important chemical gas exchanges occur between the polar snowpack and the atmosphere, and that sunlit snow is one of the most photochemically- and oxidatively-active regions of the entire troposphere.

The overarching goal of this research is to study the interaction of atmospheric ozone with the permanent snowpack based on flux-tower measurements at Summit, Greenland. The ozone exchange [Ve(O3)] above the snow surface is not a simple constant value as some climate models assume, but is highly dependent on environmental conditions (e.g., solar radiation, wind speed, atmospheric stability) and on the snowpack chemistry (e.g., nitrogen oxides, formaldehyde).

Throughout the spring, positive and negative values for Ve(O3) were observed and vertical flux divergence was negligible. During the summer, Ve(O3) exhibited a noticeable diurnal variation, where statistically significant downward/positive Ve(O3) occurred in the afternoon hours (starting around solar noon). A distinctive vertical flux divergence with height also occurred during the same period, suggesting that chemical ozone production above the snow is possible.

Meanwhile, snowpack ozone concentration showed a distinct diurnal depletion/recovery cycle, much stronger during summer than spring. This cycle, primarily affected by solar radiation penetrating the upper snowpack layer, indicates that photochemical ozone loss mechanisms are likely active and their intensities are season-dependent. In addition, the seasonal change in temperature gradients showed that the snowpack is dramatically more affected than the atmosphere itself, leading to speculate on a) chemistry occurring in the quasi-liquid layer around snow grains and b) thermal gas adsorption/desportion.

While the dynamics of the snowpack ozone and the surface layer ozone should be correlated, the complex dynamical processes are not yet clearly identifiable. Nonetheless, these analyses showed that a) snowpack ozone is depleted by either chemical and/or physical processes and b) atmospheric ozone above the snow surface is possibly produced by the hydrocarbon-nitrogen cycle.

If ozone- and other gas-transport from the more polluted mid-latitude regions were to increase, it is suspected that this active air-snow gas exchange for ozone (among the many other chemical species also found in the polar atmosphere and snowpack) would be affected. This would in turn affect the chemistry of polar snow, which in turn feeds back onto atmospheric gas budgets, and thus on global climate change.