Investigating Arctic Boundary Layer Ozone Depletions: Sodar, Lidar and Microwave Profiler Measurements on the Frozen Arctic Ocean
Abstract
Even though it has been more than 20 years since the discovery of the episodic depletion of tropospheric ozone in the Arctic during springtime, our understanding of the chemical and physical processes involved is still incomplete. Next to the difficulty of measuring the minute concentrations of the relevant halogen compounds, the main reason for this deficiency is the inaccessibility of the Arctic Ocean, which has meant that with minor exceptions the only data available thus far have been from coastal stations. The Circumpolar Flaw Lead (CFL) study in 2008 provided a unique platform for sophisticated measurements directly on the frozen ocean. For the first time, a combination of ground-level ozone sensors, a DIAL ozone lidar, a microwave temperature and humidity profiler, a sodar, and a MAX-DOAS was employed to characterize the Arctic boundary layer over the ocean. It is shown that depletions always grew from the ground up, and were eroded from aloft. The onset of depletions was generally associated with a drop in wind speeds, allowing the formation of a stable surface inversion with colder and drier air near the surface. Depletions were terminated by higher wind speeds eroding this stable surface layer. The depth of the depleted air mass was typically 300 - 600 m. BrO shows a strong diurnal pattern with daytime levels up to 30 ppt in ozone depleted air. In cases where local depletion mechanisms dominated over advection, the depletion rate was typically -3 ppb/hr.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.A51C0108S
- Keywords:
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- 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0368 Troposphere: constituent transport and chemistry;
- 0394 Instruments and techniques;
- 3307 Boundary layer processes;
- 3339 Ocean/atmosphere interactions (0312;
- 4504)