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

• Published in: Quarterly Journal of the Royal Meteorological Society
• Main Authors: Madonna, M, Li, C, Grams, C, Woollings, T
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Royal Meteorological Society 2017
• Subjects: Greenland; North Atlantic
• Online Access: https://doi.org/10.1002/qj.3155; https://ora.ox.ac.uk/objects/uuid:d76036b3-5f54-4b77-bb3f-85fe54562183

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.