Title: North Atlantic centers of action and seasonal to subseasonal temperature variability in Europe and eastern North America

Authors: Mahmoud Osman, Benjamin Zaitchik, Hamada Badr, Sultan Hameed

Journal: International Journal of Climatology

URL: https://doi.org/10.1002/joc.6806

 

Temperature variability in eastern North America and Europe is often associated with the North Atlantic Oscillation (NAO) phenomenon. The NAO is one of the most prominent patterns of atmospheric circulation variability in the Northern Hemisphere and represents the difference between the strength of two pressure systems: the low near Iceland and the high near the Azores/Bermuda. In this study, Osman et al. (2020) have examined each of the NAO composing centers separately, in terms of their influence on the air temperature in both winter and summer in eastern North America and Europe on sub-monthly (10 days) to seasonal timescales.

Results of the study show significant associations between the components of each pressure center and temperature variability at seasonal timescales. Specifically, the location of the pressure center shows associations with temperature variability that cannot be seen in NAO indices or the pressure systems’ strength. In the winter, the strength and location of the Icelandic Low are significant, while in summer the locations of both the Azores high and Icelandic low show associations with maximum temperature that are more clear and stronger than those found for the strength of the centers of action or NAO indices. The sub-monthly analyses with the centers of action and NAO indices suggest weak associations with temperature variability in eastern North America and Europe and should be considered carefully within forecast models. In conclusion, the “centers of action” approach is a powerful method to investigate the statistical relationships between teleconnections such as NAO and meteorological variability.