V I. Periodicities in European weather

Abstract

1. The present investigation was undertaken with a view to determining to what extent the variations of meteorological factors might be ascribed to periodicities, and to what extent it might be possible to forecast the general nature of the weather for long distances ahead. It was considered also that any evidence of the existence of periodicities of the same length and phase, in observations made at stations situated at wide distances apart, would afford some clue to the nature of the large scale movements of the atmosphere. 2. The Observations Used. A search was made for all the series of observations which extended over a minimum of 100 years. It was found that a number of records of temperature, rainfall and pressure were started about 1764, and eventually 12 sets of observations were selected. Monthly means or totals for 100 years were used in the investigation of periods up to 10 years, and for periods greater than 10 years all the annual values which were readily available were used. The data employed are given in the Tables in the Appendix. These tables give all the data used, and only those data. The sources from which the data were taken are shown below.