Datei:Winter-NAO-Index.png

Quelle: Wikimedia Commons; http://commons.wikimedia.org/wiki/Image:Winter-NAO-Index.png;
Source: graph drawn by Hanno using data published on the web by J.W. Hurrell (Climate Analysis Section, National Center for Atmospheric Research, Boulder, Colorado, USA) as "Climate indices" http://www.cgd.ucar.edu/cas/jhurrell/indices.html

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