Temporal variations of the “european grosswetterlagen” and possible causes

Abstract

An approximation of the annual frequencies of the “European Grosswetterlagen” (GWL) by fourth degree polynomials shows that the GWL HM and S(GT) are characterized by an inverse trend during the period 1881–1973. The periodic frequency variations of the GWL are determined by a “Maximum Entropy Spectrum Analysis”. Apart from 20–30 year periods, it is found that 13–17, 12–10 and approximately 5 year periods (in addition to a 2–3 year period) are significant. Connections between the meridional circulation and the 4.3–4.6 year fluctuations in North Atlantic ocean temperature are proved significant by analyses of coherence. Bandpass filtering of some solar indices, as well as of the monthly GWL frequencies with respect to a 2 year period, indicate new possible relationships between these two parameters.