Regional Assessment of GCM-Simulated Current Climate over Northern Canada

Several international Global Climate Models (GCMs) are evaluated on their ability to simulate the mean values and spatial variability of current (1961–90) temperature and precipitation over four regions across Canada’s North. A number of observed climate data sets for Arctic Canada are also assessed. Results reveal a close correspondence, particularly for temperature, among the four observed climate data sets assessed. However, the various GCM simulations of this observed climate show considerable inter-regional and seasonal variability, with temperature more accurately simulated than precipitation. Temperature findings indicate that the British HadCM3, German ECHAM4, and Japanese CCSR-98 models best replicate annual and seasonal values over all sub-regions. The Canadian CGCM2 and U.S. NCAR-PCM models have intermediate accuracy, and the Australian CSIRO-Mk2b and U.S. GFDL-R30 models are least representative. Temperature simulations from the various GCMs collectively display a similar degree of accuracy over all sub-regions, with no clear evidence of superiority in any given area. Precipitation, conversely, is accurately simulated by the majority of models only over northern Quebec/Labrador. All GCMs substantially overestimate annual and seasonal precipitation amounts in the western and central Canadian Arctic.Plusieurs modèles de climats du globe (MCG) internationaux ont été évalués quant à leur aptitude à simuler les valeurs moyennes et la variabilité spatiale de températures et de précipitations récentes (1961-1990) dans quatre régions du Nord canadien. Certains ensembles de données sur le climat observé dans l’Arctique canadien sont également évalués. Les résultats révèlent une correspondance étroite, surtout pour ce qui est de la température, entre les quatre ensembles de données de climats observés qui font l’objet d’une évaluation. Cependant, les diverses simulations de MCG quant au climat observé affichent une grande variabilité entre les régions et les saisons, les températures faisant l’objet de simulations plus précises que les précipitations. Les constatations en matière de précipitations laissent supposer que les modèles HadCM3 britannique, ECHAM4 allemand et CCSR-98 japonais répliquent mieux les valeurs annuelles et saisonnières dans toutes les sous-régions. Pour leur part, les modèles CGCM2 canadien et NCAR-PCM américain présentent une exactitude intermédiaire, tandis que les modèles CSIRO-Mk2b australien et GFDL-R30 américain sont les modèles les moins représentatifs. Ensemble, les simulations de températures des divers modèles MCG affichent un degré semblable d’exactitude dans toutes les sous-régions, sans qu’il n’y ait de modèle nettement supérieur dans une région donnée. Réciproquement, les précipitations sont simulées avec exactitude par la majorité des modèles dans le nord du Québec et le Labrador seulement. Tous les MCG surestiment, de manière substantielle, les quantités de précipitations annuelles et saisonnières dans l’ouest et dans le centre de l’Arctique canadien

Limitations of Water Resources Infrastructure for Reducing Community Vulnerabilities to Extremes and Uncertainty of Flood and Drought

Debate and deliberation surrounding climate change has shifted from mitigation toward adaptation, with much of the adaptation focus centered on adaptive practices, and infrastructure development. However, there is little research assessing expected impacts, potential benefits, and design challenges that exist for reducing vulnerability to expected climate impacts. The uncertainty of design requirements and associated government policies, and social structures that reflect observed and projected changes in the intensity, duration, and frequency of water-related climate events leaves communities vulnerable to the negative impacts of potential flood and drought. The results of international research into how agricultural infrastructure features in current and planned adaptive capacity of rural communities in Argentina, Canada, and Colombia indicate that extreme hydroclimatic events, as well as climate variability and unpredictability are important for understanding and responding to community vulnerability. The research outcomes clearly identify the need to deliberately plan, coordinate, and implement infrastructures that support community resiliency.Fil: McMartin, Dena W.. University of Regina; CanadáFil: Hernani Merino, Bruno H.. University of Regina; CanadáFil: Bonsal, Barrie. Environment Canada; CanadáFil: Hurlbert, Margot. University of Regina; CanadáFil: Villalba, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientifícas y Tecnológicas; ArgentinaFil: Ocampo, Olga L.. Universidad Autónoma de Manizales; ColombiaFil: Upegui, Jorge Julián Vélez. Universidad Nacional de Colombia; ColombiaFil: Poveda, Germán. Universidad Nacional de Colombia; ColombiaFil: Sauchyn, David J.. University of Regina; Canad

Special Issue: Past and Future Trends and Variability in Hydro-Climatic Processes

The earth has vast amounts of surface and sub-surface freshwater in the form of lakes, reservoirs, rivers, wetlands, soil water, groundwater, as well as water stored in snowpacks, glaciers, and permafrost [...

Assessment of Canadian prairie drought : past, present, and future

Within Canada, the Canadian Prairies are particularly drought-prone mainly due to their location in the lee of the western cordillera and distance from large moisture sources. Although previous studies examined the occurrence of Canadian Prairie droughts during instrumental, pre-instrumental and to a lesser extent, future periods, none have specifically focused on all time three scales. Using two different drought indicators, namely the Palmer Drought Severity Index (PDSI) and Standardized Precipitation Index (SPI), this investigation assesses the variability of summer drought duration and intensity over a core region of the Prairies during (a) the pre-instrumental record extending back several centuries (inferred from tree rings), (b) the instrumental record (1901–2005), and (c) the twenty-first century using statistically downscaled climate variables from several Atmosphere–Ocean Global climate models with multiple emission scenarios. Results reveal that observed twentieth century droughts were relatively mild when compared to pre-settlement on the Prairies, but these periods are likely to return (and even worsen) in the future due to the anticipated warming during the course of the twenty-first century. However, future drought projections are distinctly different between the two indices. All PDSI-related model runs show greater drought frequency and severity mainly due to increasing temperatures. Conversely, the precipitation-based SPI indicates no significant changes to future summer drought frequency although there tends to be a higher persistence of multi-year droughts in central and southern portions of Canadian Prairies. These findings therefore stress the importance of considering anticipated warming trends when assessing future regional-scale drought, especially given the uncertainties and lack of consistency in future precipitation signals among climate models. This study can be considered an initial step toward quantifying and understanding Canadian Prairie drought occurrence and severity over several centuries as determined from paleo, instrumental, and climate model data sources

Characterizing the Water Balance of the Sooke Reservoir, British Columbia over the Last Century

Infrastructure such as dams and reservoirs are critical water-supply features in several regions of the world. However, ongoing population growth, increased demand and climate variability/change necessitate the better understanding of these systems, particularly in terms of their long-term trends. The Sooke Reservoir (SR) of British Columbia, Canada is one such reservoir that currently supplies water to ~300,000 people, and is subject to considerable inter and intra-annual climatic variations. The main objectives of this study are to better understand the characteristics of the SR through an in-depth assessment of the contemporary water balance when the basin was intensively monitored (1996–2005), to use standardized runoff to select the best timescale to compute the Standard Precipitation (SPI) and Standard Precipitation Evaporation Indices (SPEI) to estimate trends in water availability over 1919 to 2005. Estimates of runoff and evaporation were validated by comparing simulated change in storage, computed by adding inputs and subtracting outputs from the known water levels by month, to observed change in storage. Water balance closure was within ±11% of the monthly change in storage on average when excluding months with spill pre-2002. The highest evaporation, dry season (1998) and lowest precipitation, wet season (2000/2001) from the intensively monitored period were used to construct a worst-case scenario to determine the resilience of the SR to drought. Under such conditions, the SR could support Greater Victoria until the start of the third wet season. The SPEI and SPI computed on a three-month timescale had the highest correlation with the standardized runoff, R2 equaled 0.93 and 0.90, respectively. A trend toward drier conditions was shown by SPEI over 1919 to 2005, while moistening over the same period was shown by SPI, although trends were small in magnitude. This study contributes a validated application of SPI and SPEI, giving more credit to their trends and estimated changes in drought

Assessment of Canadian prairie drought : past, present, and future

Within Canada, the Canadian Prairies are particularly drought-prone mainly due to their location in the lee of the western cordillera and distance from large moisture sources. Although previous studies examined the occurrence of Canadian Prairie droughts during instrumental, pre-instrumental and to a lesser extent, future periods, none have specifically focused on all time three scales. Using two different drought indicators, namely the Palmer Drought Severity Index (PDSI) and Standardized Precipitation Index (SPI), this investigation assesses the variability of summer drought duration and intensity over a core region of the Prairies during (a) the pre-instrumental record extending back several centuries (inferred from tree rings), (b) the instrumental record (1901–2005), and (c) the twenty-first century using statistically downscaled climate variables from several Atmosphere–Ocean Global climate models with multiple emission scenarios. Results reveal that observed twentieth century droughts were relatively mild when compared to pre-settlement on the Prairies, but these periods are likely to return (and even worsen) in the future due to the anticipated warming during the course of the twenty-first century. However, future drought projections are distinctly different between the two indices. All PDSI-related model runs show greater drought frequency and severity mainly due to increasing temperatures. Conversely, the precipitation-based SPI indicates no significant changes to future summer drought frequency although there tends to be a higher persistence of multi-year droughts in central and southern portions of Canadian Prairies. These findings therefore stress the importance of considering anticipated warming trends when assessing future regional-scale drought, especially given the uncertainties and lack of consistency in future precipitation signals among climate models. This study can be considered an initial step toward quantifying and understanding Canadian Prairie drought occurrence and severity over several centuries as determined from paleo, instrumental, and climate model data sources

Towards the incorporation of hydrogeochemistry into the modelling of permafrost environments: a review of recent recommendations, considerations, and literature

This study is a meta-analysis of recent global research articles on hydrogeochemical modelling of permafrost regions to determine trends and consensus on research gaps and future research directions. The hydrogeochemical response of permafrost to climate change remains challenging to estimate and forecast despite evidence of large-scale impacts on freshwater and ecological cycles. We investigate the feasibility, need, and potential for hydrogeochemical modelling of permafrost landscapes by reviewing recommendations from previous modelling, review, and primer papers, including discussing ways to advance this type of modelling science. Key permafrost hydrogeochemical processes are discussed, including heat transfer and associated freeze–thaw regimes, biogeochemical processes and rates, and surface and subsurface flow. Modelling considerations (i.e., model dimension, scale, heterogeneity, and permafrost zonation) and model parameters are subsequently examined. Finally, limitations and additional considerations for advancing permafrost hydrogeochemical modelling efforts are reviewed. The findings of this review are summarized in recommendations, tables, and two schematics incorporating key considerations for future hydrogeochemical modelling initiatives in permafrost environments

Western Canadian freshwater availability: current and future vulnerabilities

The western cordillera supplies freshwater across much of western Canada mainly through meltwater from snow and ice. This “alpine water tower” has been, and is projected to be, associated with changes in the seasonality and amount of freshwater availability, which are critical in supporting the societal and environmental flow needs of the region. This study incorporates existing information to synthesize and evaluate current and future freshwater supplies and demands across major north-, west-, and east-flowing sub-basins of the Canadian western cordillera. The assessment of supply indicators reveals several historical changes that are projected to continue, and be exacerbated, particularly by the end of this century and under a high emission scenario. The greatest and most widespread impact is the seasonality of streamflow characterized by earlier spring freshets, increased winter, and decreased summer flow. Future winter and spring warming over all basins will result in decreases in end of season snow and glacier mass balance with greatest declines in more southern regions. In many areas, there will be a greater likelihood of summer freshwater shortages. All sub-basins have environmental and economic freshwater demands and pressures, especially in more southern watersheds where population and infrastructure are more prevalent and industrial, agricultural, and water energy needs are higher. Concerns regarding the continued ability to maintain suitable aquatic habitats and adequate water quality are issues across all regions. These water supply changes along with continued and increasing demands will combine to create a variety of freshwater vulnerabilities across all regions of western Canada. Southern basins including the South Saskatchewan and Okanagan are likely to experience the greatest vulnerabilities due to future summer freshwater supply shortages and increasing economic demands. In more northern areas, vulnerabilities primarily relate to how the rapidly changing landscape (mainly associated with permafrost thaw) impacts freshwater quantity and quality. These vulnerabilities will require various adaptation measures in response to alterations in the timing and amount of future freshwater supplies and demands.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author