An assessment of historical and projected future hydro‐climatic variability and extremes over southern watersheds in the Canadian Prairies

Abstract

Since human activities and ecosystem health require adequate, reliable water supplies, hydro-climatic variability and extremes pose serious threats to society and the environment. Previous studies have shown that the Canadian Prairies normally experience considerable hydro-climatic variability, including periodic droughts and excessive moisture conditions, which are mainly caused by mid-tropospheric circulations that disrupt expected precipitation and temperature patterns. However, no investigations have specifically focused on both past and future hydro-climatology over watersheds within the region. Evaluation of the Standardized Precipitation Evapotranspiration Index reveals considerable inter-annual and decadal-scale variability over the study regions of the Oldman and Swift Current Creek Watersheds, with no discernible trends during the last ∼100 years. There is also an indication of increased variability since the mid-1980s. Assessment of the 500 hPa circulation patterns associated with identified hydro-climatic extremes shows that major droughts are related with higher frequencies of distinctive ridging patterns over the Prairie region, and lower incidences of zonal/troughing patterns (the former significantly increasing over the last 60 years). Excessive moisture conditions have opposite patterns. Projections from two (a drier/warmer and wetter/cooler) Regional Climate Models indicate an uncertain future in the selected watersheds ranging from a substantial increase in drought with a higher degree of inter-annual variability, to relatively no change from current conditions. Furthermore, future changes to key atmospheric circulations suggest that those patterns associated with extreme dry conditions will continue in the future and in some cases, increase in frequency. Results from this analysis have improved the understanding of historical hydro-climatic extremes in western Canada and have provided insight into potential future occurrences of these extremes as driven by changes to key surface climate and synoptic-scale atmospheric circulation patterns.

Re-Evaluating the Climate Factor in Agricultural Land Assessment in a Changing Climate—Saskatchewan, Canada

“…Crop production data from 2005 to 2016 show an increase in the average yield, and this trend is consistent with projections of higher crop yields in a warming climate [6,7]. Research suggests that crop producers could benefit from a warming climate [5,8], provided that agricultural practices and policies can be adapted to withstand increased climatic variability [9,10]. Climate model projections show warming temperatures increased precipitation (i.e., in the amount and timing, as well as the form), but also increased evapotranspiration, which will result in decreased summer soil moisture [4,11,12].…”

Atmospheric drivers of winter above‐freezing temperatures and associated rainfall in western Canada

“…In addition, it provides new insight into winter hydroclimatic conditions, particularly as it relates to persistence of atmospheric regimes through the grouping of synoptic types into similar regimes. Previous studies evaluate trends in the frequency of synoptic types (e.g., Newton et al, ; ; Bonsal et al, ; Bonsal and Cuell, ); however, this study uses a new approach to identify statistical step‐changes in synoptic type frequency, which may be beneficial for the evaluation of thresholds related to system changes or the generation of extremes (e.g., McGregor, ). An important aspect not explored in this research is within‐type climatic trends and variability, driven by air mass thermodynamic characteristics (e.g., Kassomenos and McGregor, ; Cassano et al, ).…”

“…Numerous studies evaluate links between atmospheric circulation patterns and surface climate and hydrology. A mid‐tropospheric ridge of high pressure centred over western Canada is linked to above‐average temperatures and below‐average precipitation while a ridge of high pressure centred over the Pacific Ocean and adjacent trough over the continent is associated with below‐average temperatures and above‐average precipitation in western Canada (Romolo et al, ; ; Newton et al, ; Bonsal et al, ; Bonsal and Cuell, ). Romolo et al .…”

Assessing the Importance of Potholes in the Canadian Prairie Region under Future Climate Change Scenarios

“…Though climate warming is not uniformly projected across the globe, results for the CPPR indicate that warming (~6 • C rise by 2070 across the basin) may be more pronounced than the global average (~2-3 • C) for the same period. Previous studies [96][97][98] highlighted that rising temperatures would act as a catalyst in enhancing evapotranspiration, which has the potential to cause more water stress in summer. The combined effects of a water availability deficit, increasing temperatures, and increasing evapotranspiration suggest the potential for increasing frequency and severity of drought.…”