j@1040: UV increase due to ozone loss
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j@1040: The chemical depletion of ozone in the stratosphere causes an increase
j@1040: of ultraviolet radiation on the ground. The UV index is a measure of
j@1040: the danger of the UV radiation.  It corresponds to the
j@1040: sunburn-effective solar irradiance.
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j@1040: This is a sample calculation [#FN1]_, how the UV index typically
j@1040: changes at a certain latitude in winter and spring.  Shown are
j@1040: noontime values of the UV index at clear sky for the range of the
j@1040: observed ozone columns of the years 2000 and 2012 (black) and
j@1040: corresponding values for a given decrease the ozone column (blue). The
j@1040: selection of the two values for geographical latitude and ozone loss
j@1040: can be altered.  The anthropogenically induced polar ozone depletion
j@1040: takes place within the polar vortex, which in winter and spring is
j@1040: well separated from the mid-latitudes.  After the breakdown of the
j@1040: polar vortex (in the Northern hemisphere typically at the latest in
j@1040: early April), ozone-rich air from mid-latitudes will be transported
j@1040: back into the polar regions.
j@1040: 
j@1040: In contrast to the Southern hemisphere, there are typically no
j@1045: significant increases to very high UV indices in polar high latitudes
j@1040: in the Northern hemisphere in the relevant period until April.
j@1040: 
j@1040: These graphs show how the maximum UV index (at noontime at clear sky)
j@1040: would change due to ozone depletion in the Arctic polar vortex.
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j@1040: .. [#FN1] The mean values and standard deviations of the ozone columns were calculated from the database of Bodeker-Scientific (http://www.bodekerscientific.com).  Calculation of the UV index for cloudless sky according to the method of Allaart et al. (Meteorological Applications, 11, 59-65, 2004)