Surface ozone depletion episodes in the Arctic and Antarctic from historical ozonesonde records D. W. Tarasick and J. W. Bottenheim Environment Canada, 4905 Dufferin Street, Downsview, ON, M3H 5T4 Canada
Abstract. Episodes of ozone depletion in the lowermost Arctic atmosphere
(0--2 km) at polar sunrise have been intensively studied at Alert, Canada, and are thought to result from catalytic reactions
involving bromine. Recent observations of high concentrations of tropospheric BrO over large areas
of the Arctic and Antarctic suggest that such depletion events should also be seen by ozonesondes at
other polar stations. An examination of historical ozonesonde records shows that such events occur
frequently at Alert, Eureka and Resolute, but much less frequently at Churchill and at other stations.
The differences appear to be related to differences in average springtime surface temperatures. The
long record at Resolute shows depletions since 1966, but with an increase in their frequency over the
period 1966--2000 of 0.66 ± 0.59% per year (95% confidence limits), explaining the apparent increase
of Hg in Arctic biota in recent times.
Citation: Tarasick, D. W. and Bottenheim, J. W.: Surface ozone depletion episodes in the Arctic and Antarctic from historical ozonesonde records, Atmos. Chem. Phys., 2, 197-205, doi:10.5194/acp-2-197-2002, 2002.