POSSIBLE CHANGES IN THE DOSE OF BIOLOGICALLY-ACTIVE ULTRAVIOLET-RADIATION RECEIVED BY THE BIOSPHERE IN THE SUMMERTIME ARCTIC DUE TO TOTAL OZONE INTERANNUAL VARIABILITY

Data for total ozone measurements since 1972 from the world ozone meas uring network have been analyzed to study ozone interannual variabilit y and estimate its possible effect on the UV-B dose received by the ar ctic biosphere. Possible interannual changes in the UV-B dose received by DNA associated with overall interannual ozone variability, as well as with the quasi-biennial oscillation (QBO) in total ozone were comp uted for different summer months. In general, the largest interannual variations in UV-B dose may occur in the Russian Arctic, whereas the p ossible variations in the Canadian Arctic are the smallest. Overall va riations in the UV-B dose received by DNA can exceed 25% (2 sigma crit erion) in the Taimyr and Severnaya Zemlya for June and July, and 30% i n the Laptev Sea for August. In the European sector of the Arctic, the possible variations are greater than 10%, and can exceed 15% in the n orth Norwegian Sea for July and 20% in Spitsbergen for August. Possibl e overall variations in the Canadian Arctic and Alaska are less than o r equal to 10%, reaching 15% in Alaska for August, however. The total ozone QBO can also cause essential and (statistically) predicted chang es in UV-B radiation. In general, the UV-B dose received by DNA is fou nd to be greater in the Arctic during the westerly phase of the QBO of the equatorial stratospheric wind at 50 mb level than during the east erly phase. The difference can reach or exceed 15% (relative to the me an value) in Taimyr for June and in Severnaya Zemlya for July and Augu st. In northern Europe and Iceland, the difference can reach 10% for A ugust. In the Canadian Arctic, the QBO-related effect is small. In Ala ska, the appropriate difference in UV-B dose has an opposite sign for August, exceeding 5% in magnitude.