The link between eddy-driven jet variability and weather regimes in the North Atlantic-European sector

• Main Authors: Madonna, Erica, Li, Camille, Grams, Christian M., Woollings, Tim
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-Blackwell 2017
• Subjects: eddy-driven jet; weather regimes; North Atlantic atmospheric variability; blocking; NAO; Greenland; North Atlantic
• Online Access: https://hdl.handle.net/20.500.11850/217030; https://doi.org/10.3929/ethz-b-000217030

This study reconciles two perspectives on wintertime atmospheric variability in the North Atlantic–European sector: the zonal-mean framework comprising three preferred locations of the eddy-driven jet (southern, central, northern), and the weather regime framework comprising four classical North Atlantic-European regimes (Atlantic ridge AR, zonal ZO, European/Scandinavian blocking BL, Greenland anticyclone GA). A k-means clustering algorithm is used to characterize the two-dimensional variability of the eddy-driven jet stream, defined by the lower tropospheric zonal wind in the ERA-Interim reanalysis. The first three clusters capture the central jet and northern jet, along with a new mixed-jet configuration; a fourth cluster is needed to recover the southern jet. The mixed cluster represents a split or strongly tilted jet, neither of which is well described in the zonal-mean framework, and has a persistence of about one week, similar to the other clusters. Connections between the preferred jet locations and weather regimes are corroborated – southern to GA, central to ZO, and northern to AR. In addition, the new mixed cluster is found to be linked to European/Scandinavian blocking, whose relation to the eddy-driven jet was previously unclear. ISSN:0035-9009 ISSN:1477-870X