Dynamical Evolution of North Atlantic Ridges and Poleward Jet Stream Displacements

• Main Authors: Tim Woollings, João A. Santos
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2010
• Subjects: Pacific; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.654.817; http://centaur.reading.ac.uk/32766/1/2011jas3661.1.pdf

The development of a particular wintertime atmospheric circulation regime over the North Atlantic, comprising a northward shift of the North Atlantic eddy-driven jet stream and an associated strong and persistent ridge in the subtropics, is investigated. Several different methods of analysis are combined to de-scribe the temporal evolution of the events and relate it to shifts in the phase of the NorthAtlantic Oscillation andEastAtlantic pattern. First, the authors identify a close relationship between northward shifts of the eddy-driven jet, the establishment and maintenance of strong and persistent ridges in the subtropics, and the oc-currence of upper-tropospheric anticyclonicRossbywave breaking over Iberia. Clear tropospheric precursors are evident prior to the development of the regime, suggesting a preconditioning of theAtlantic jet streamand an upstream influence via a large-scale Rossby wave train from the North Pacific. Transient (2–6 days) eddy