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UP: Umweltphysik

UP 9: Atmosphäre, Aerosole, Klima - Poster

UP 9.3: Poster

Montag, 18. März 2002, 16:30–18:00, Galerie 1

Bromine Oxide Measurements at the Hudson Bay by Multi-Axis-DOAS and Active Longpath-DOAS — •Gerd Hönninger, Hans Leser, Oliver Sebastian, and Ulrich Platt — Institut für Umweltphysik, Universität Heidelberg, INF 229, 69120 Heidelberg

During sudden ozone depletion events in the polar boundary layer (BL) after sunrise, bromine oxide radicals (BrO) play a key role in catalytic ozone destruction cycles. BrO in the atmosphere can be measured using Differential Optical Absorption Spectroscopy (DOAS). It has first been detected in the BL at high Arctic sites using active Longpath-(LP)-DOAS with an artificial light source. Multi-Axis-(MAX)-DOAS is a novel technique, which combines zenith sky and off-axis DOAS measurements of scattered sunlight. In spring 2001 the first simultaneous measurements of BrO using both LP-DOAS and MAX-DOAS were carried out in the Canadian low Arctic. The interest in the Hudson Bay region based on GOME satellite maps which show enhanced BrO vertical columns in this area during spring. Here the results of the first ground-based measurements at Kuujjuarapik, Quebec, Canada (55^∘N, 75^∘W) are presented and discussed. Several episodes of enhanced BrO (up to 30 ppt) in the boundary layer correlated to ozone losses from background levels of about 40 ppb to less than 10 ppb were monitored. The data measured by MAX-DOAS and LP-DOAS independently are shown and the advantages and drawbacks of both methods are compared.