NORTH ATLANTIC OSCILLATION – CONCEPTS AND STUDIES

• Main Authors: Heinz Wanner, Stefan Brönnimann, Jürg Luterbacher, Christoph Schmutz, Eleni Xoplaki
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2001
• Subjects: to Northern Hemisphere annular mode; NAM; AOGCM – Atmosphere-Ocean General Circulation; Arctic; Iceland; North Atlantic; North Atlantic oscillation
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.134.5009; http://secamlocal.ex.ac.uk/people/staff/dbs202/publications/2001/climdyn_2002_wanner_broenn.pdf

Abstract. This paper aims to provide a comprehensive review of previous studies and concepts concerning the North Atlantic Oscillation. The North Atlantic Oscillation (NAO) and its recent homologue, the Arctic Oscillation/Northern Hemisphere annular mode (AO/NAM), are the most prominent modes of variability in the Northern Hemisphere winter climate. The NAO teleconnection is characterised by a meridional displacement of atmospheric mass over the North Atlantic area. Its state is usually expressed by the standardised air pressure difference between the Azores High and the Iceland Low. This NAO index is a measure of the strength of the westerly flow (positive with strong westerlies, and vice versa). Together with the El Niño/Southern Oscillation (ENSO) phenomenon, the NAO is a major source of seasonal to interdecadal variability in the global atmosphere. On interannual and shorter time scales, the NAO dynamics can be explained as a purely internal mode of variability of the atmospheric circulation. Interdecadal variability may be influenced, however, by