News & Events

Multi-year observations of O3 and NOx dynamics in Summit, Greenland snowpack

Thursday, February 28, 2013, 4:30PM - 5:30PM

Speaker

Brie Van Dam

Location:

RL-1 room 269

Photochemical and physical processes in the polar snowpack have been shown to exhibit significant influence on tropospheric trace gas budgets in polar regions. In this research we use a multi-year record of ozone (O3) and nitrogen oxides (NOx) in snowpack interstitial air down to a depth of 2.8 m at Summit, Greenland to investigate mechanisms controlling how the snow acts as a source or sink of these constituents. O3 depletion within the snowpack is observed throughout all seasons, and the magnitude of depletion closely tracks the seasonal cycle in incoming solar radiation. NO production within a shallow layer of the snowpack is recorded during the spring and summer months. NO2 production also occurred, and heightened levels are measured down to 2.5 m in the snowpack. The average daily maximum in NO was observed at solar noon, and the minimum was seen during night. The daily peak in NO2 occurred on average 7 hours after the incoming solar radiation and NO maximums.  The influence of meteorological effects such as wind pumping on snowpack interstitial air levels of O3 and NOx were investigated using several case study periods. Results detail the significance of these chemical and physical processes in determining levels of O3 and NOx within and above the Summit snowpack.