In 1988 Barrie et al.  drew attention to the startling drop in O3 at polar sunrise at Alert and the concomitant increase in filterable Bromine (f-Br). As shown in the paper of Bottenheim in this workshop, the measurements indicated sharp periodic drops in the mixing ratio of O3 with a time scale of several hours or less. On occasions the O3 levels would be below the detection limit of the instruments used. Simultaneously, they confirmed dramatic increase in the levels of f-Br (more than 100 times the levels anticipated from sea salt aerosols) that had been measured earlier by Berg et al. . (Although one should point out that different filters had been used. In addition, one uses the term “simultaneously” loosely since the time of a single measurement is substantially longer for the f-Br measurements than for the O3 measurements.) Many measurements since that time have confirmed the negative-correlation between the O3 and the f-Br [e.g., Bottenheim et al., 1990; Oltman et al., 1989 etc.] and the effect has been observed at Barrow as well as Alert. Seasonal measurements of O3 at Barrow indicate values well below the yearly average during polar sunrise. The sharp depletion seems to be correlated with stable conditions in the boundary layer with the depletion of O3 occurring only within the first kilometer.
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- Ozone Depletion during Polar Sunrise
John C. McConnell
Grant S. Henderson
- Springer Berlin Heidelberg