Europe’s darker atmosphere in the UV-B

Abstract

Irradiation in the ultraviolet wavelength range is found to be up to 50% lower in the European summer compared to sites with comparable latitudes in New Zealand. We have developed a method to quantitatively attribute the causes for such differences between sites by analysis of spectra. We conclude that these large differences are caused mainly by differences in total ozone, cloudiness, aerosol loading and Sun-Earth separation. The relative contribution of clouds varies from year to year and it is site dependent. Averaged over several years we find a strong latitudinal gradient of the cloud impact within Europe, with much less cloud attenuation in southern Europe. Due to the differences in total ozone and aerosol loading, the UV-B levels are generally lower in Europe compared to New Zealand. It is likely that inter-hemispheric differences will change in coming decades due to a combination of changes in ozone concentrations, air pollution and cloudiness as a result of climate change. However, since the future evolution of these major parameters is highly uncertain, the magnitude and even the sign of such changes are not known yet.

Cellular Changes Associated with the Acclimation of the Intertidal Sea AnemoneActinia tenebrosato Ultraviolet Radiation

“…Over the past 50 years, stratospheric ozone concentrations have declined significantly in polar and midlatitude regions , as a consequence of the use of chlorine and bromide containing substances. While modeling of these changes in the ozone layer have projected a partial recovery of the ozone layer over the next 2–3 decades, due to the transport of ozone‐poor air from Antarctica , large differences in the UV‐B (290–320 nm) radiation doses have been observed at midlatitudes when the Southern and Northern hemispheres are compared . For example, Lauder (46°S, New Zealand) receives 50% more UV‐B radiation than Garmisch (47°N, Germany) during the summer season .…”

“…While modeling of these changes in the ozone layer have projected a partial recovery of the ozone layer over the next 2–3 decades, due to the transport of ozone‐poor air from Antarctica , large differences in the UV‐B (290–320 nm) radiation doses have been observed at midlatitudes when the Southern and Northern hemispheres are compared . For example, Lauder (46°S, New Zealand) receives 50% more UV‐B radiation than Garmisch (47°N, Germany) during the summer season . Furthermore, small‐scale ozone depletion events known as mini ozone holes can reduce the total ozone column by 40%, increasing the penetration of UV‐B at midlatitudes .…”

The Network for the Detection of Atmospheric Composition Change (NDACC): History, status and perspectives

“…Differences between corresponding latitudes in the Northern and Southern Hemispheres can be attributed to differences in cloudiness, total ozone, aerosol loading, Sun-Earth separation, altitude, and albedo [Seckmeyer et al, 2008b;Bais et al, 10 24 Atmos. Chem.…”

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“…For the past three decades these increases in the levels of UV-B have been greater in the Southern Hemisphere than the Northern Hemisphere [5]. As a consequence, marine organisms inhabiting southern mid-latitude regions can receive up to 50% more UV-B radiation than those in the Northern Hemisphere [6].…”