Possible Impacts of Climate Change on Freezing Rain Using Downscaled Future Climate Scenarios: Updated for Eastern Canada

Abstract

The methods used in an earlier study focusing on the province of Ontario, Canada, were adapted for this current study to expand the study area over eastern Canada where the infrastructure is at risk of being impacted by freezing rain. To estimate possible impacts of climate change on future freezing rain events, a three-step process was used in the study: (1) statistical downscaling, (2) synoptic weather typing, and (3) future projections. A regression-based downscaling approach, constructed using different regression methods for different meteorological variables, was used to downscale the outputs of eight general circulation models to each of 42 hourly observing stations over eastern Canada. Using synoptic weather typing (principal components analysis, a clustering procedure, discriminant function analysis), the freezing rain-related weather types under historical climate and future downscaled climate conditions (2016-2035, 2046-2065, 2081-2100) were identified for all selected stations. The potential changes in the frequency of future daily freezing rain events can be projected quantitatively by comparing future and historical frequencies of freezing rain-related weather types.The modelled results show that eastern Canada could experience more freezing rain events late this century during the coldest months (i.e., December to February) than the averaged historical conditions. Conversely, during the warmest months of the study season (i.e., November and April in the southern regions, October in the northern regions), eastern Canada could experience less freezing rain events late this century. The increase in the number of daily freezing rain events in the future for the coldest months is projected to be progressively greater from south to north or from southwest to northeast across eastern Canada. The relative decrease in magnitude of future daily freezing rain events in the warmest months is projected to be much less than the relative increase in magnitude in the coldest months.RÉSUMÉ [Traduit par la rédaction] Nous avons adapté pour la présente étude les méthodes utilisées dans une étude précédente concernant l'Ontario, au Canada, afin d'étendre la zone étudiée à l'est du Canada où l'infrastructure risque d'être touchée par la pluie verglaçante. Pour estimer les répercussions possibles du changement climatique sur les événements de pluie verglaçante futurs, nous avons adopté un processus en trois étapes dans cette étude : (1) la réduction statistique, (2) le typage des conditions synoptiques et (3) les projections dans le futur. Nous avons employé une méthode de réduction basée sur la régression, construite à l'aide de différentes techniques de régression pour différentes variables météorologiques, pour réduire les sorties de huit modèles de circulation générale à chacune de 42 stations d'observations horaires dans l'est du Canada. Au moyen du typage des conditions synoptiques (analyse des composantes principales, une procédure d'agrégation, analyse discriminante), nous avons identifié les types m...

Simulated Changes in the Freezing Rain Climatology of North America under Global Warming Using a Coupled Climate Model

“…The results of the present study are broadly consistent with those of Cheng et al (2007) and partially supported by Cheng et al (2011). It is encouraging that these studies yield similar results even though they use different diagnostic methods.…”

“…In a subsequent paper, Cheng et al (2011) extended the analysis to include the eastern half of southern Canada. These results are similar to those reported in Cheng et al (2007) in that, under global warming, freezing rain events are projected to increase more in northern areas than in southern areas, with all regions exhibiting an increase in freezing rain events.…”

A method to estimate freezing rain climatology from ERA-Interim reanalysis over Europe

“…Bernstein and Le Bot, 2009;Le Bot and Lassegues, 2004). More comprehensive studies have been undertaken on ice storm and FZRA climatologies over North America, including studies for various regions (Cortinas, 2000;Changnon, 2003;Cortinas et al, 2004), impacts of ice storms on different sectors (Proulx and Greene, 2001), and changes in FZRA climatology (Cheng et al, 2007(Cheng et al, , 2011Lambert and Hansen, 2011;Klima and Morgan, 2015) as well as on various wintertime precipitation types (Stewart et al, 2015) and impacts and details of FZRA storms and related synoptics (Hosek et al, 2011;Call, 2010;Roberts et al, 2008).…”

On the Characteristics of and Processes Producing Winter Precipitation Types near 0°C

“…Hanesiak and Wang (2005) inferred an increase in freezing rain occurrence in some areas of the Canadian Arctic. Furthermore, Cheng et al (2011) and Lambert and Hansen (2011) inferred future freezing rain occurrence using climate scenario information over North America. Both studies predicted a substantial northward shift of the belt of freezing rain.…”