edu.ucar.opensky::articles:12288 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T03:57:08.163108 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d78k79v2 Coupling between Greenland blocking and the North Atlantic Oscillation pattern 2012-07-21T00:00:00Z publication https://n2t.org/ark:/85065/d78k79v2 https://doi.org/10.1029/2012GL052315 Davini, P. author Cagnazzo, C. author Neale, Richard author Tribbia, Joseph author UCAR/NCAR - Library publisher Through the adoption of a bidimensional blocking index based on geopotential height, it is shown that the blocking frequency over Greenland is not only a key element in describing the North Atlantic Oscillation (NAO) index, but it also operates as an essential element in modulating its pattern. When Greenland blocking is lower than average, the first Empirical Orthogonal Function (EOF) of the 500 hPa geopotential height over the Euro-Atlantic region no longer resembles the NAO. Moreover, the typical trimodal variability observed in the Atlantic eddy-driven jet stream is reduced to a bimodal variability. Consistent with this result, we link the eastward displacement of the NAO pattern observed in recent years to the decreasing frequency of Greenland Blocking. Considering the large bias seen in the simulated blocking frequency in climate models, such strong coupling might have important consequences in the analysis of the NAO in climate simulations. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2012 American Geophysical Union. None eng geoscientificInformation