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Medientyp: E-Artikel Titel: Non‐negative Matrix Factorization for the identification of patterns of atmospheric pressure and geopotential for the Northern Hemisphere Beteiligte: Schlink, Uwe; Thiem, Alexander Erschienen: Wiley, 2010 Erschienen in: International Journal of Climatology Sprache: Englisch DOI: 10.1002/joc.1942 ISSN: 0899-8418; 1097-0088 Schlagwörter: Atmospheric Science Entstehung: Anmerkungen: Beschreibung: <jats:title>Abstract</jats:title><jats:p>As the atmospheric system is characterized by highly complex interactions between a large number of physical variables, it is a challenging task for researchers to break up the complicated structures into a few significant modes of variability.</jats:p><jats:p>An innovative technique, called Non‐negative Matrix Factorization (NMF), developed to provide a reduced‐dimensional representation of large‐scale non‐negative data and to extract underlying features, is introduced as a tool for meteorological applications. The method is used to decompose space‐time meteorological fields into spatial patterns and associated time indices in order to advance our knowledge of dominant atmospheric processes. For the Northern Hemisphere the 500 hPa geopotential field together with sea level pressure (SLP) are analysed using an up‐to‐date NMF algorithm as well as a helpful method of NMF initialization based on Singular Value Decomposition (SVD). Several NMF patterns correspond to the variations identified by traditional EOF analysis, such as the East Atlantic and the Pacific/North American Pattern. For the North Atlantic Oscillation the NMF identifies sub‐patterns: The positive phase is associated with systems of pressure variation over the Pacific Ocean and the Arctic, respectively, the negative phase resembles the EOF pattern.</jats:p><jats:p>As the NMF patterns not only represent variability, like EOF patterns, but also are fractions of the total observed values, we demonstrate for a location near Nikolski, Alaska, the temporal development of the geopotential as a superposition of NMF‐factors. Copyright © 2009 Royal Meteorological Society</jats:p> Zugangsstatus: Freier Zugang