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| Titel |
High levels of ultraviolet radiation observed by ground-based instruments below the 2011 Arctic ozone hole |
| VerfasserIn |
G. Bernhard, A. Dahlback, V. Fioletov, A. Heikkilä, B. Johnsen, T. Koskela, K. Lakkala, T. Svendby |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 21 ; Nr. 13, no. 21 (2013-11-01), S.10573-10590 |
| Datensatznummer |
250085780
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| Publikation (Nr.) |
 copernicus.org/acp-13-10573-2013.pdf |
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| Zusammenfassung |
| Greatly increased levels of ultraviolet (UV) radiation were observed at
thirteen Arctic and sub-Arctic ground stations in the spring of 2011, when the
ozone abundance in the Arctic stratosphere dropped to the lowest amounts on
record. Measurements of the noontime UV Index (UVI) during the low-ozone
episode exceeded the climatological mean by up to 77% at locations in
the western Arctic (Alaska, Canada, Greenland) and by up to 161% in
Scandinavia. The UVI measured at the end of March at the Scandinavian sites
was comparable to that typically observed 15–60 days later in the year when
solar elevations are much higher. The cumulative UV dose measured during the
period of the ozone anomaly exceeded the climatological mean by more than two
standard deviations at 11 sites. Enhancements beyond three standard
deviations were observed at seven sites and increases beyond four standard
deviations at two sites. At the western sites, the episode occurred in March,
when the Sun was still low in the sky, limiting absolute UVI anomalies to
less than 0.5 UVI units. At the Scandinavian sites, absolute UVI anomalies
ranged between 1.0 and 2.2 UVI units. For example, at Finse, Norway, the
noontime UVI on 30 March was 4.7, while the climatological UVI is 2.5.
Although a UVI of 4.7 is still considered moderate, UV levels of this amount
can lead to sunburn and photokeratitis during outdoor activity when radiation
is reflected upward by snow towards the face of a person or animal. At the
western sites, UV anomalies can be well explained with ozone anomalies of up
to 41% below the climatological mean. At the Scandinavian sites, low
ozone can only explain a UVI increase of 50–60%. The remaining
enhancement was mainly caused by the absence of clouds during the low-ozone
period. |
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