INCREASED ULTRAVIOLET-RADIATION IN NEW-ZEALAND (45-DEGREES-S) RELATIVE TO GERMANY (48-DEGREES-N)

RECENT analyses of global ozone measurements have confirmed that ozone reductions are not confined to the Antarctic, but now extend to mid-latitudes in both hemispheres1,2. Ozone reductions lead to increases in biologically damaging ultraviolet radiation3, and such increases have been observed in Antarctica1,4 and Australia5. Little is known, however, about hemispheric differences in ultraviolet intensities. Here we use a combination of spectral measurements made in Germany and New Zealand with the same spectroradiometer, together with model calculations, to show that in the New Zealand summer of 1990-1991 biologically weighted ultraviolet irradiances were nearly a factor of two greater than those in the summer at similar northern latitudes in Germany. These differences are larger than expected3,6, and are due mainly to decreased stratospheric ozone over New Zealand and increased levels of tropospheric ozone over Germany.