Climate of Our Future

ScienceDaily (Nov. 22, 2008) — In the Arctic in spring, the snow cover gives off nitrogen oxides. This phenomenon, the extent of which had not been previously realized, is the source of one third of the nitrates present in the Arctic atmosphere, according to researchers from CNRS, the Université Joseph Fourier and the Université Pierre et Marie Curie[1]

They made a quantitative study of the origin and evolution of nitrogen compounds in the Arctic atmosphere, in order to understand their environmental impact on this region. These findings are published in the 31 October 2008 issue of the journal Science.

In the Arctic, the snow that covers the land mass and the pack ice is a constant source of new surprises for researchers. One of the major players in climate change, it is also closely monitored by atmospheric chemists, who suspect it of being behind fundamental alterations in atmospheric composition in spring, when sunshine returns.

The researchers had already studied episodes of total destruction of ozone at the surface of the Arctic snow cover [2] as well as the role played by this cover in the dangerous mercury ‘rain’ that pollutes ecosystems [3]. This time they were interested in the ability of the arctic snow cover to interact with nitrogen compounds such as nitrogen oxides and atmospheric nitrate. At temperate latitudes nitrogen oxides are produced not only by natural phenomena such as lightning and forest fires, but also by human activity, such as combustion in engines and industrial activity. They are the cause of the peaks in ozone concentration observed on the outskirts of cities during episodes of high pollution. Nitrogen oxides are rapidly oxidized to nitrate, which, incorporated into atmospheric particulate matter, is transported by air currents, bringing surplus nitrogen to distant ecosystems. Keep Reading