2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference

Evolving trends of rain over precipitation in Canadian cold season during the late 20th century

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Mrs. Shadi Hatami, Concordia University (Presenter)
Dr. Ali Nazemi, Concordia University
Mr. Amirali Amir Jabbari, Concordia University

Cold season across the Canadian landmass is prolonged and includes regionally important hydrological processes, such as snowfall and snow accumulation, which provides a reliable freshwater resource during the warm season, in which the majority of environmental and socio-economic activities take place. Canada however is in the forefront of climate change effects and this implies less snow during the cold season. Understanding the historical evolution in characteristics of cold season precipitation during the recent past is therefore important for evaluating the extent of climate change and is insightful for provision of adaptive water management in the country. Here we study the evolution in ratio of rain over total precipitation (R/P) during the cold-season at 46 high-quality stations in Canada during the common period of 1961 to 2000. We examine the trend in consecutive 10-, 20- and 30-year episodes at each station to provide a notion of evolution in monotonic change in form of cold season precipitation across the country. A coefficient of variation for moving trend is defined to compare the evolution in trends between different Canadian regions. Our findings clearly illustrate consistent increments in significant trends in 30-year episodes in Atlantic and Central Canada as well as the West Coast, while more variability in evolutions of trends are observed for in 10 and 20 years. Further study shows that in majority of stations, the evolution in 30-year trends in R/P during the cold season coincides with the evolution of trend in mean temperature.