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

Historical and Projected Changes to the Stages and Other Characteristics of Severe Canadian Prairie Droughts

Large-area, long-duration droughts are among Canada’s costliest natural disasters. A particularly vulnerable region includes the Canadian Prairies where droughts have, and are projected to continue to have, major impacts. However, individual droughts often differ in their stages such as onset, growth, persistence, retreat, and duration. Using the Standardized Precipitation Evapotranspiration Index, this study assesses historical and projected future changes to the stages and other characteristics of severe drought occurrence across the agricultural region of the Canadian Prairies. Ten severe droughts occurred during the 1900–2014 period with each having unique temporal and spatial characteristics. Projected changes from 29 global climate models (GCMs) with three representative concentration pathways reveal an increase in severe drought occurrence, particularly toward the end of this century with a high emissions scenario. For the most part, the overall duration and intensity of future severe drought conditions is projected to increase mainly due to longer persistence stages, while growth and retreat stages are generally shorter. Considerable variability exists among individual GCM projections, including their ability to simulate observed severe drought characteristics. This study has increased understanding in potential future changes to a little studied aspect of droughts, namely, their stages and associated characteristics. This knowledge can aid in developing future adaptation strategies

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 [...

Possible teleconnections between North Pacific sea surface temperatures and extended dry spells and droughts on the Canadian Praries

This thesis examines the possible teleconnections between North Pacific sea surface temperatures and synoptic extended dry spells and droughts on the Canadian Prairies. Dry spells are a natural occurrence on the Canadian Prairies. It is also a well known fact that extended dry spells often lead to droughts. The major synoptic cause of extended dry spells and droughts on the Canadian Prairies includes the presence of a quasi-stationary mid-tropospheric ridge over the area. What causes this ridge to become quasi-stationary is not certain. Some previous studies have shown that sea surface temperature anomalies over the North Pacific Ocean may be a significant factor in affecting upper atmospheric long wave patterns and abnormal weather conditions over North America. The main objective of this study is to determine if there is a significant statistical relationship between anomalous North Pacific sea surface temperatures and the occurrence of extended dry spells and droughts on the Canadian Prairies during the agricultural growing season (May - August) for the period 1948-1988. Individual extended dry spells are identified and then ranked in terms of their severity. Results show a significant correlation between these extended dry spells and a positive sea surface temperature anomaly gradient located in the east central North Pacific. This gradient consists of a region of anomalously cold water located in the east-central North Pacific in the area bounded by 30°N to 40°N latitude and 165°W to 135°W longitude and a region of anomalously warm water found along the west coast of North America bounded by the coordinates 45°N to 55°N latitude and 130°W to 125°W longitude. A probability model shows that the longer this gradient persists, the greater the probability of a major extended dry spell. A conceptual model is also constructed and shows a distinctive pattern in sea surface temperature anomalies and 50 kPa anomalies associated with the major extended dry spells

Teleconnections between ENSO events and growing season precipitation on the Canadian Prairies

Teleconnections between ENSO events and growing-season precipitation variations on the Canadian Prairies are examined. Correlation and composite analyses indicate that between 1948 and 1991, El Nino events were associated with more frequent extended dry spells. Conversely, La Nina events coincided with fewer extended dry spells. Both relationships occurred during the third growing season following the onset of the ENSO events (i.e. approximately a 10-season or 30-month lag). A series of atmosphere - ocean teleconnections over the Pacific Ocean including Pacific North America (PNA) circulation patterns, North Pacific sea-surface temperature anomalies and upper-atmospheric circulation anomalies were found to result in growing-season precipitation variations over the Canadian Prairies. Results of this analysis are incorporated into a conceptual model which may form the basis of a long-range forecasting technique of growing-season precipitation variations on the Canadian Prairies

Compound Extremes of Droughts and Pluvials: A Review and Exploration of Spatio-Temporal Characteristics and Associated Risks in the Canadian Prairies

The Canadian Prairies are associated with high natural hydroclimatic variability including the frequent periodic occurrence of droughts and pluvials. These extremes carry various risks including significant damage to the economy, environment and society. The well-documented level of damage necessitates further risk assessment and planned reductions to vulnerability, particularly in light of a warming climate. A logical starting point involves awareness and information about the changing characteristics of such climate extremes. We focus on the compound occurrence of droughts and pluvials as the risks from this type of event are magnified compared to the hydroclimatic extremes in isolation. Compound droughts and pluvials (CDP) are drought and pluvial events that occur in close succession in time or in close proximity in area. Also, research on CDP is limited even for the worldwide literature. Therefore, the purposes of this paper are to synthesize recent literature concerning the risks of CDP, and to provide examples of past occurrences, with a focus on the Canadian Prairies. Since literature from the Prairies is limited, global work is also reviewed. That literature indicates increasing concern and interest in CDP. Relationships between drought and pluvials are also characterized using the SPEI Global Monitor for the Prairies, emphasizing the recent past. Research mostly considers drought and pluvials as separate events in the Prairies, but is integrated here to characterize the relationships of these extremes. The spatiotemporal patterns showed that several of the extreme to record pluvials were found to be closely associated with extreme droughts in the Prairies. The intensities of the extremes and their dry to wet boundaries were described. This is the first research to explore the concept of and to provide examples of CDP for the Prairies and for Canada. Examples of CDP provide insights into the regional hydroclimatic variability. Furthermore, most literature on future projections strongly suggests that this variability is likely to increase, mainly driven by anthropogenic climate change. Therefore, improved methods to characterize and to quantify CDP are required. These findings suggest means of decreasing vulnerability and associated damages. Although the study area is the Canadian Prairies, the work is relevant to other regions that are becoming more vulnerable to increasing risks of and vulnerabilities to such compound extremes