Characteristics of Icing Events in Quebec

摘要

More than 20 years of recorded observations of atmospheric icing are now available from 180 Passive Ice Meter stations throughout the province of Quebec, Canada. The objective of this study is to analyze the data and to develop regional design criteria for telecommunication and electric transmission towers. The first phase of the project is to find the best site-specific statistical model for the intensity of glaze ice accumulation. In order to increase the sample size, an event-based model, in which every icing event is counted as an independent event, is adopted. Different definitions of what constitutes an icing event are examined and compared with results based on annual maximum values. The comparison, based on the goodness-of-fit of different probability distribution functions and the sampling characteristics of the extrapolated right tail of the distributions, shows that the event-based model provides better results from a statistical point of view. The next phase of the project is to develop procedures for spatial interpolation to locations where there are presently no measuring stations. The latter requires the estimation of the recurrence rate of icing storms, their spatial extent, and the identification of site specific features that increase the ice storm hazards. The spatial interpolation of the quantiles of the distributions shows the need for more sophisticated scheme that incorporates other meteorological and topographic parameters.