Summary
Records of precipitation events are examined for five stations in southern Ontario for evidence of trends or oscillations in the variability. It is concluded that there is little evidence for this since 1940, although there were oscillations before this period from runs of events above the median to events below the median for the one station with a record from 1879. There are distinct trends in the 5 year running means, however, since 1940. Episodes of event maxima are found in the late 1940’s and early 1950’s as well as within the last decade, and a minimum is in the early 1960’s. A comparison of the variance in the precipitation events with that of hydroelectric power generation illustrates several periods of coincident deviations of both the same and opposite sign, although not more than expected by chance.
Zusammenfassung
Aufzeichnungen von Niederschlagsepisoden wurden für fünf Stationen im südlichen Ontario im Hinblick auf Tendenzen und Oszillationen in ihrer Variabilität untersucht. Seit 1940 bestehen nur geringe Anzeichen für derartige Vorgänge, obwohl vor diesem Termin eine Station mit Daten seit 1879 Oszillationen in Folgen oberhalb und unterhalb des Medianwertes aufwies. In den fünfjährig übergreifenden Mitteln zeigen sich jedoch seit 1940 deutliche Tendenzen. Maxima in den Episoden traten zum Ende der vierziger Jahre und zu Beginn der fünfziger Jahre auf, Minima dagegen zu Beginn der sechziger Jahre. Ein Vergleich zwischen der Veränderlichkeit des Niederschlages und der hydroelektrischen Kraftstromerzeugung weist Perioden paralleler und antiparalleler Abweichungen auf, die mehr oder weniger dem Zufallsgesetz entsprechen.
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LeDrew, E.F., Amsden, S.L. An examination of precipitation variability in Southern Ontario using event records. Arch. Met. Geoph. Biocl., Ser. B 34, 83–95 (1984). https://doi.org/10.1007/BF02275677
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DOI: https://doi.org/10.1007/BF02275677