Recent polar ozone depletion and the concomitant increase in surface ultraviolet (UV) radiation may be expected to adversely influence the polar biosphere. To investigate the effect of long-term changes in total column ozone on the spatial and temporal variability of biologically harmful radiation, daily global ozone maps have been obtained from two satellite experiments and used as input to a simple radiative transfer model. Four different data products of erythemally weighted irradiance, at monthly resolution, and in 1 degrees latitude zones, were produced for the period 1979 to 1994; the time period spanned by the satellite experiments. The results show that significant increases in erythemal UV can be expected over Antarctica and the surrounding oceans over this period. In contrast, increases over the high latitudes of the Northern Hemisphere are significantly smaller. The magnitude of the hemispheric differences in the long-term change in surface UV irradiance will be sensitive to the action spectrum (biological weighting function) applied. For biological processes responding to UV in a similar way to the erythemal action spectrum, this study suggests that the marginal ice zone of the Antarctic continent provides the best site for investigations of the effects of enhanced UV-B as a result of ozone depletion.
