Summary and synthesis of Changing Cold Regions Network (CCRN) research in the interior of western Canada – Part 1: Projected climate and meteorology

Abstract

Abstract. The interior of western Canada, up to and including the Arctic, has experienced rapid change in its climate, hydrology, cryosphere, and ecosystems, and this is expected to continue. Although there is general consensus that warming will occur in the future, many critical issues remain. In this first of two articles, attention is placed on atmospheric-related issues that range from large scales down to individual precipitation events. Each of these is considered in terms of expected change organized by season and utilizing mainly “business-as-usual” climate scenario information. Large-scale atmospheric circulations affecting this region are projected to shift differently in each season, with conditions that are conducive to the development of hydroclimate extremes in the domain becoming substantially more intense and frequent after the mid-century. When coupled with warming temperatures, changes in the large-scale atmospheric drivers lead to enhancements of numerous water-related and temperature-related extremes. These include winter snowstorms, freezing rain, drought, forest fires, as well as atmospheric forcing of spring floods, although not necessarily summer convection. Collective insights of these atmospheric findings are summarized in a consistent, connected physical framework.

Near-0 °C surface temperature and precipitation type patterns across Canada

“…For example, under saturated conditions aloft with rising air, cloud droplets can be produced that can then be subsequently captured by falling precipitation particles. The ensuing rimed, more dense particles require greater fall distances and/or higher temperatures to melt (Stewart et al, 2019).…”

“…Regionally, Stewart and Yiu (1993) examined near-0 • C conditions including their horizontal scales and associated precipitation over southern Ontario. In terms of associated precipitation, MacKay and Thompson (1969) published the first climatology of freezing precipitation for Canada, and this was later updated by Stuart and Isaac (1999) and Wang (2006). Many case study analyses of heavy precipitation and/or freezing rain events have been carried out to investigate storm structure and the associated precipitation production mechanisms (e.g., Henson et al, 2007Henson et al, , 2011.…”

Summary and synthesis of Changing Cold Regions Network (CCRN) research in the interior of western Canada – Part 2: Future change in cryosphere, vegetation, and hydrology

“…Thus, it is spatially highly variable over heterogeneous landscapes, and is sensitive to changing climate and to land cover change (Zha et al, 2010). Changes in P amount and character are controlled to a considerable degree by global and continental-scale conditions and their influence on regional circulation, air mass characteristics, and smaller scale variability (e.g., Stewart et al, 2019). Some further considerations of interactions at the surface and land-atmosphere feedbacks that affect local P processes are discussed here.…”

“…Human interventions and land and water management have also affected the environment and river systems, with infrastructure developments such as dams, diversions, and irrigation networks, along with industrialization, agricultural development, and urbanization, thereby altering natural ecosystems and water cycling. Future projections of warmer climate, altered P phase and patterns, and more extreme events (Bush and Lemmen, 2019;Stewart et al, 2019), together with increasing human pressures, indicate that the region will continue to undergo rapid change to conditions never before experienced, posing difficult management and decision-making challenges (e.g., Razavi et al, 2020). Improved understanding and prediction of the changes in coupled climate-land-hydrological systems are crucial for managing land and water systems, and informing governance and policy direction here and in other similar regions globally.…”

Hydrological Extremes in the Canadian Prairies in the Last Decade due to the ENSO Teleconnection—A Comparative Case Study Using WRF

“…The Canadian Prairie provinces of Alberta, Saskatchewan, and Manitoba are known for their extreme seasonal climate and large interannual variability of hydrometeorological parameters [1,2]. Precipitation exhibits the largest spatial and temporal variability [3,4]. The major drivers of the interannual variability are the teleconnections with various large-scale climate patterns, especially El Niño Southern Oscillation (ENSO) [5][6][7][8].…”