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| Titel |
Possible impacts of climate change on freezing rain in south-central Canada using downscaled future climate scenarios |
| VerfasserIn |
C. S. Cheng, H. Auld, G. Li, J. Klaassen, Q. Li |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 7, no. 1 ; Nr. 7, no. 1 (2007-01-22), S.71-87 |
| Datensatznummer |
250004329
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| Publikation (Nr.) |
 copernicus.org/nhess-7-71-2007.pdf |
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| Zusammenfassung |
Freezing rain is a major atmospheric hazard in mid-latitude nations of the
globe. Among all Canadian hydrometeorological hazards, freezing rain is
associated with the highest damage costs per event. Using synoptic weather
typing to identify the occurrence of freezing rain events, this study
estimates changes in future freezing rain events under future climate
scenarios for south-central Canada. Synoptic weather typing consists of
principal components analysis, an average linkage clustering procedure
(i.e., a hierarchical agglomerative cluster method), and discriminant
function analysis (a nonhierarchical method). Meteorological data used in
the analysis included hourly surface observations from 15 selected weather
stations and six atmospheric levels of six-hourly National Centers for
Environmental Prediction (NCEP) upper-air reanalysis weather variables for
the winter months (November–April) of 1958/59–2000/01. A statistical
downscaling method was used to downscale four general circulation model
(GCM) scenarios to the selected weather stations. Using downscaled
scenarios, discriminant function analysis was used to project the occurrence
of future weather types. The within-type frequency of future freezing rain
events is assumed to be directly proportional to the change in frequency of
future freezing rain-related weather types
The results showed that with warming temperatures in a future climate,
percentage increases in the occurrence of freezing rain events in the north
of the study area are likely to be greater than those in the south. By the
2050s, freezing rain events for the three colder months (December–February)
could increase by about 85% (95% confidence interval – CI: ±13%),
60% (95% CI: ±9%), and 40% (95% CI: ±6%) in northern Ontario, eastern Ontario (including Montreal, Quebec),
and southern Ontario, respectively. The increase by the 2080s could be even
greater: about 135% (95% CI: ±20%), 95% (95% CI: ±13%), and 45% (95% CI: ±9%). For the three warmer months
(November, March, April), the percentage increases in future freezing rain
events are projected to be much smaller with some areas showing either a
decrease or little change in frequency of freezing rain. On average,
northern Ontario could experience about 10% (95% CI: ±2%) and
20% (95% CI: ±4%) more freezing rain events by the 2050s and
2080s, respectively. However, future freezing rain events in southern
Ontario could decrease about 10% (95% CI: ±3%) and 15%
(95% CI: ±5%) by the 2050s and 2080s, respectively. In eastern
Ontario (including Montreal, Quebec), the frequency of future freezing rain
events is projected to remain the same as it is currently. |
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