• Open Access

Are there weekly cycles in occurrence frequencies of large-scale circulation types?



The existence of weekly cycles in occurrence frequency distributions of circulation types is examined on the basis of a comprehensive data base of automated circulation-type classifications for the greater North Atlantic European region and sub-domains during the period 1957–2002. The main result is that the percentage of circulation types for which a statistical significant weekly cycle (95% level of confidence) could be detected by a chi-square goodness-of-fit test does not exceed the number that would be expected by chance. Thus it is concluded that no consistent weekly cycles in occurrence frequencies of circulation types exist. Copyright © 2012 Royal Meteorological Society