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The impact of nitrogen chemistry in snow on atmospheric oxidising capacity in the polar boundary layer

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Wednesday, 18 October 2017, 12:00

 

Wednesday, October 18, 2017. 12:00PM. Snow surfaces do not only influence the albedo feedback on Earth but also have a significant impact on the chemistry of the overlying air. Light-induced chemical reactions take place in the snow leading to emissions of reactive chemical species such as ni. Veronica Chan, British Antarctic Survey. Sponsored by GFDL. More information here.

 

Snow surfaces do not only influence the albedo feedback on Earth but also have a significant impact on the chemistry of the overlying air. Light-induced chemical reactions take place in the snow leading to emissions of reactive chemical species such as nitrogen oxides, an ozone precursor, which can alter ozone concentration in the lower atmosphere. Tropospheric ozone is a pollutant and a greenhouse gas that can influence the regional energy balance and climate. This project aims at developing a model to quantify the emissions of nitrogen species from snow for the following reasons: 1) In the Arctic, there is strong interest in near-term mitigation of the current warming by controlling tropospheric ozone precursors as the level of nitrogen oxide has doubled since the mid-twentieth century due to fossil fuel burning from the shipping industries. To provide an accurate assessment of how effective the adopted mitigation measures are it is necessary to understand the natural background air chemistry and take into account the chemical snow source. 2) Climate models predict the largest temperature rise in the polar regions which would certainly change the chemical snow source. The consequences of the changing climate on nitrogen emission from snow and the feedback via tropospheric ozone level will be constrained. 3) Ice cores are powerful archives of past climate and environmental conditions, from seasonal to multi-millennial timescales. However, photoreactions and physical processes within the snowpack do influence nitrate concentrations and currently prevent a quantitative interpretation of the polar ice core record of nitrate.

 

 

Location  Smagorinksy Seminar Room, NOAA GFDL, Princeton, NJ.