Possible Influence of Solar Activity on Trajectories of Extratropical Cyclones in the North Atlantic: An Update

Abstract

In this article we continue studying the influence of solar activity on the main trajectories of extratropical cyclones (storm tracks) in different parts of the North Atlantic during the cold half of the year (period of intense cyclogenesis). Long-term oscillations in the latitude of storm tracks in the areas located west and east of the Greenwich meridian are compared. It is shown that secular oscillations in latitudes of storm tracks (with periods of ∼80–100 years) are most distinctly pronounced in the western North Atlantic (longitudes 60°–40° W), weaken in the area of the Icelandic Low (30°−10° W), and completely disappear in the eastern part (0°−20° E), where multidecadal oscillations with periods of ∼50–60 years dominate. Bidecadal oscillations in cyclone trajectories (northward shift of trajectories during the declining phase and at the minima of even-numbered solar cycles) have the greatest amplitude in the region of the Icelandic Low and noticeably weaken east of Greenwich. It is shown that the shift of cyclone trajectories to the north in even cycles occurs under increased galactic cosmic ray (GCR) intensity compared to odd cycles. The data providing evidence for the influence of the stratospheric polar vortex on the position of North Atlantic cyclone trajectories are presented. It is suggested that possible reasons for oscillations in the vortex intensity are changes in the chemical composition and temperature regime of the middle polar stratosphere caused by variations in GCR fluxes and geomagnetic activity.