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The [http://www.drinetwork.ca/ Drought Research Initiative](DRI) has been established "to better understand the physical characteristics of and processes influencing Canadian Prairie droughts, and to contribute to their better prediction, through a focus on the recent severe drought that began in 1999 and largely ended in 2005" <ref>[http://www.drinetwork.ca/objective.php Drought Research Initiative Mission Statement]</ref>. It is an interdisciplinary effort that involves 15 funded investigators from 6 Canadian universities and more than 20 collaborators from other universities and federal laboratories as well as partners from three provincial governments ([[Alberta]], [[Manitoba]] and [[Saskatchewan]]). <br /> |
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== Drought in Canada == |
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DRI is achieving its objective by focusing on five complementary research themes, including quantification, understanding, prediction, comparisons with other droughts, and implications for society. Readers wishing more detail than is available in this entry should read Stewart et al (2008)<ref name="Stewart">Stewart, R., J. Pomeroy and R. Lawford, 2008: A Drought Research Initiative for the Canadian Prairies, CMOS Bulletin, Vol. 36, No. 3, 97-102.</ref> or explore the [http://www.drinetwork.ca/ DRI website] |
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[[Image:Canadian Precipitation Anomalies 2002.jpg|thumb|300px|Average precipitation departures from normal over Canada from autumn 2000 through summer 2002. Precipitation departures are relative to the 1961-90 reference period.]] |
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== Background == |
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[[Image:Canadian Annual PDSI Timeseries.jpg|thumb|300px|Annual Palmer Drought Severity (PDSI) values for a) Kamloops, BC, b) Saskatoon, SK, c) Sherbrooke, QC, and d) Yarmouth, NS. Solid lines represent 10-year running means. (Source: Climate Research Branch, Meteorological Service of Canada, Environment Canada, Downsview, ON.]] |
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[[Drought]] is an anomaly within the atmospheric, surface and sub-surface cycling of water and energy, usually initiated through large to regional scale atmospheric processes, and enhanced and maintained through regional to local {earth's atmosphere|atmospheric]], [[Surface-water hydrology|surface hydrology]], [[land surface]] and [[groundwater]] feedbacks that operate throughout the annual cycle. Droughts are a distinctive feature of the [[Drought in Canada|Canadian Prairies]] where the large scale [[atmospheric circulation|atmospheric circulations]] are influenced by [Block (meteorology)|blocking] from intense [[orography]] to the west and long distances from all warm ocean-derived atmospheric water sources. <br /> |
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Prolonged, large-area [[drought|droughts]] are among [[Canada|Canada’s]] costliest natural disasters having major impacts on a wide range of sectors including [[agriculture]], [[forestry]], [[industry]], [[municipalities]], [[recreation]], [[human health]] and [[society]],and [[ecosystems]]. They frequently stress water availability by depleting [[soil moisture]], reducing [[stream flow|stream flows]], lowering lake and reservoir levels, and diminishing [[groundwater]] supplies. This ultimately affects several economic activities including for example, decreased agricultural production, less hydro-electric power generation, and increased freshwater transportation costs. Droughts also create major environmental hazards such as reduced [[water quality]], [[wetland]] loss, [[soil erosion]] and [[soil degradation|degradation]], and ecological habitat destruction. |
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DRI addresses a mulit-year drought that began in 1999 with cessation of its atmospheric component in 2004/2005 and many of its hydrological components in 2005. It was the worst drought for at least a hundred years in parts of the [[Canadian Prairies]]. According to Phillips (2002)<ref name="phillips">Phillips, D.W., 2002: The top ten Canadian weather stories for 2001. CMOS Bulletin, 30, 19-23.</ref>, for the western and central Canadian Prairies during 2001 and 2002, “… it was the worst of times. Even in the dust bowl of the 1930s, no single year between Medicine Hat, Kindersley and Saskatoon was drier than in 2001”. The drought affected agriculture, recreation, tourism, health, hydro-electricity, and forestry in the Prairies. [[Gross Domestic Product]] fell some $5.8 billion and employment losses exceeded 41,000 jobs for 2001 and 2002. This drought also contributed to a negative or zero net farm income for several provinces for the first time in 25 years ([[Statistics Canada]], 2003<ref name="Statistics">Statistics Canada, 2003: Net Farm Income. Catalogue No. 21-010-XIE, Volume 2. Ottawa, Ontario.</ref>) with agricultural production over Canada dropping an estimated $3.6 billion in 2001/2002. Previously reliable water supplies such as streams, wetlands, dugouts, reservoirs, and groundwater were placed under stress and often failed. More details are available in Wheaton (2006).<br /> |
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Despite the enormous economic, environmental, and societal impacts of droughts, DRI is undertaking the first integrated drought research program of its kind in Canada with the hope being that the occurrence and nature of drought can be better anticipated on short and long term scales. From a longer-term perspective, this 5-year Network represents an essential step in better predicting droughts over Canada, their detailed structure and their impacts with increasing confidence and better assessing whether there will be a ‘drying of the continental interior’ in the future |
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==Research Themes== |
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Although most regions of Canada have experienced drought, southern regions of the [[Canadian Prairies]] and [[British Columbia Interior|interior British Columbia]] are most susceptible. During the past two centuries, at least 40 droughts have occurred in western Canada with multi-year episodes being observed in the 1890s, 1910s, 1930s, 1960s, 1980s, and the early 2000s. Droughts in southern Ontario/Quebec are usually shorter, smaller in area, less frequent, and less intense. Nonetheless, there have been some major drought occurrences during the 20th century. Droughts in the [[Atlantic Provinces]] occur even less frequently. Droughts are less of a concern for [[northern Canada]] mainly due to their lower population densities. However, increased frequencies of forest fires during drought years can have serious economic impacts. |
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DRI is achieving its objective by focusing on five complementary research themes, including quantification, understanding, and better prediction of a particular drought with funding primarily from the [[Canadian Foundation for Climate and Atmospheric Sciences|Canadian Foundation for Climate and Atmospheric Sciences (CFCAS)]]. Comparisons with other droughts, and implications for society have been funded with additional direct and in-kind support coming from [[Environment Canada]], [[Agriculture and Agri-Food Canada]], [[Natural Resources Canada]], [[Prairie Farm Rehabilitation Administration|Prairie Farm Rehabilitation Administration (PFRA)]], [[Saskatchewan Watershed Authority]], [[Saskatchewan Research Council]], [[Manitoba Water Stewardship]] and [[Manitoba Hydro]]. |
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Rarely has drought been as serious or extensive as the recent 1999-2004 episode <ref>[http://www.drinetwork.ca/impacts.php Drought Research Initiative: Drought Impacts]</ref>. This event produced the worst drought for at least a hundred years in parts of the Canadian Prairies. Well below normal precipitation was reported in areas of [[Alberta]] and [[Saskatchewan]] for more than four consecutive years extending from autumn 1999 to spring 2004. No single year on record between [[Medicine Hat]], [[Kindersley]], and [[Saskatoon]] was drier than in 2001. The years 2001 and 2002 may have also brought the first coast-to-coast droughts on record, and were rare as they struck areas less accustomed to dealing with droughts including parts of [[Atlantic Canada]] and the northern agricultural prairies (see Figure 1). Canada’s [[Gross Domestic Product]] fell $5.8 billion for 2001 and 2002. In addition, previously reliable water supplies such as streams, wetlands, reservoirs, and groundwater were placed under stress and often failed. For example, the number of natural Prairie ponds in May 2002 was the lowest on record while in 2001, Great Lakes-St. Lawrence water levels plunged to their lowest point in more than 30 years thereby significantly increasing marine transportation costs. In [[British Columbia]] and [[Manitoba]], [[Hydroelectricity|hydro-electric]] generation was curtailed, necessitating additional purchases of power from neighboring jurisdictions. In 2002, the incidence of forest fires in Alberta increased to five times the ten-year average while in summer 2003, populated regions of interior British Columbia were stricken by drought-enhanced fires. Long-lasting impacts included soil degradation by wind erosion and deterioration of grasslands that could take decades and longer to recover. |
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===1: Characterizing Drought=== |
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High surface temperatures can intensify droughts by enhancing [[evapotranspiration]] in summer, and increasing [[sublimation]] and melting of the [[snowpack]] during winter. During the 20th century, mean annual [[air temperature]] has increased by around 1.0°C over southern Canada with the greatest warming in the west and the largest rates during winter and spring. Over the same period, annual [[precipitation]] has significantly increased over most of southern Canada with the exception of southern Alberta and Saskatchewan. Coincident with the large increases in spring temperature, the 1980s to the present have been associated with rapid reductions in [[snow cover]] during the second half of the snow season. Over the last 30 to 50 years, average [[stream flow]] has decreased in many parts of Canada with significant reductions in the south. Great Lakes’ water levels have shown substantial variability during the 20th century with no evidence of a long-term trend. Lower levels coincided with the droughts of the 1930s, early 1960s, and the recent 1999-2001 dry period. Over the Prairies, the numbers and water levels of wetlands have shown no clear trend over the last 40 to 50 years. |
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To characterize the drought of 1999-2005 DRI has been quantifying its atmospheric, hydrologic, and land-surface physical features at a variety of spatial and temporal scales. This analysis will be realized by addressing three focused questions: |
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[[drought indices|Indices]] used to measure drought show considerable decadal-scale variability with no long-term trends discernible in any portion of the country. Most southern regions of Canada, however, were associated with drought conditions during the late 1990s to early 2000s. The worst and most prolonged Canadian Prairie-wide droughts during the [[Instrumental temperature record|instrumental period]] occurred in the early part of the 20th century (1920s and 1930s). [[Paleoclimatology|Paleo]] studies over the southwestern Canadian Prairies using [[Dendrochronology|tree ring chronologies]] dating back to 1597 indicate that the 20th century lacked the prolonged droughts of the 18th and 19th centuries when droughts were evident for decades at a time. |
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*What variables are required to quantify the characteristics of this recent drought? |
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*What data sources and model outputs are available for quantification of these parameters? |
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*How do we characterize and “close the budgets” of water and energy over the Prairies? . |
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The analysis has involved the development of a four-dimensional assessment of the atmosphere during the drought over various temporal scales using a knowledge of [[temperature]], [[humidity]], [[geopotential height]], [[wind]], [[clouds]], [[precipitation]] amount, and current [[weather]]. At the surface, the spatial and temporal characteristics of vegetative state (in terms of [[water stress]]) for major vegetation types ([[crop|crops]] and [[boreal shield|boreal zones]]), [[soil moisture]], [[drainage basin|stream network]], [[river flows]], lake levels, [[wetlands]], [[depression storage capacity|depression storage]], [[groundwater]] and [[subsurface flow|sub-surface flows]] be assessed to determine when and where drought is occurring. Although this is a difficult task due to data gaps, and the complexity of the shallow undulations in the prairies [[topography]], an analysis of [[in-situ]] data, [[earth observation satellite|satellite]]data and model output now provides a comprehensive overview of the evolution of the drought. |
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== Causes == |
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===2: Drought Processes=== |
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DRI is also focusing on the understanding of the processes and feedbacks governing the formation, evolution, cessation and structure of the drought. This theme addresses the following questions: |
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Although considerable research has been carried out on [[drought|droughts]], there is still no complete theory that explains their formation, persistence, and termination. The major factor in the onset and continuation of drought involves distinctive [[atmospheric circulation|circulation patterns]] in the [[upper atmosphere]]. Over the Canadian Prairies for example, [[growing season]] extended dry periods are associated with a persistent atmospheric circulation pattern that includes a large-amplitude[[Ridge (meteorology)|ridge]] centred over the area. This ridge creates [[Block (meteorology)|‘blocking conditions’]] that displace [[Storm track|storm tracks]] away from the area. Drought can also be initiated and/or accentuated during winter when a lack of snowfall results in lower than normal spring [[Surface runoff|runoff]] and thus, reduced stream flow and reservoir and soil moisture replenishment. Reduced winter precipitation is also caused by persistent atmospheric circulation patterns that involve [[Ridge (meteorology)|ridging]] over the affected area. |
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*What processes were responsible for the onset of the recent drought? |
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*What processes and feedbacks contributed to the drought’s evolution, persistence, and spatial structure? |
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*What processes and feedbacks controlled the termination of this drought? |
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There are many ways in which drought, basically a sustained precipitation deficit, can be initiated and prolonged. Some processes that reduce precipitation include, large scale circulation anomalies, lack of moisture advected into a region, reduction of local moisture supplies, production of [[virga]] as opposed to precipitation, and possibly even the role of [[aerosols]] in the dusty environment acting to reduce precipitation. Over the five years of this drought, these processes and numerous other factors were operating at various times and locations to preclude substantial precipitation from being produced over large regions of the Prairies. <br /> |
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While prairie drought processes have characteristic spatial and temporal scales, land surface hydrological/biophysical processes generally operate at small spatial scales (and with larger inherent spatial variability) while atmospheric process have a hierarchy of scales ranging from planetary to local turbulence. DRI is addressing the cascade of energy and movement of moisture through atmospheric processes and the horizontal scale link between land surface and groundwater processes during drought events. |
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===3: Drought Prediction === |
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Reasons for the persistence of circulation patterns that lead to drought are not entirely understood but are likely related to surface boundary conditions such as [[snow cover|snow]] and [[ice cover]], vegetation, soil moisture, and [[sea-surface temperatures]] (SSTs) that force the [[climate system]] through variations in their optical and thermal properties. These forcing factors directly influence local to regional atmospheric flow which in turn, can affect [[Atmospheric circulation|large-scale circulation]] over other areas of the globe (known as [[Teleconnection|teleconnections]]). For Canada, significant relationships between [[El Niño]]<ref>[http://www.smc-msc.ec.gc.ca/education/elnino/index_e.cfm El Niño fact sheet], from the [[Meteorological Service of Canada]]</ref> and La Niña<ref>[http://www.smc-msc.ec.gc.ca/education/lanina/index_e.cfm La Niña fact sheet ],from the [[Meteorological Service of Canada]]</ref> events and winter/spring temperature and precipitation have been determined. In general, [[El Niño]] is associated with warmer/drier winters while [[La Niña]] has an opposite effect. Linkages between Canadian climate and teleconnections such as the [[Pacific Decadal Oscillation]] and the [[North Atlantic Oscillation]] are also evident, but mainly during the winter season. [[Teleconnection|Teleconnections]] during summer are not as strong. However, recent research has shown that some [[El Niño]] events are associated with a summer moisture deficit in the western two-thirds of Canada while La Niñas produce an abundance of summer moisture in extreme western Canada. The considerable lag between summer moisture and large-scale SSTs provides a basis for developing [[Long range weather forecasts|long-range forecasting]] of drought conditions in Canada. |
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Drought prediction research in DRI is directed at assessing and reducing uncertainties in the prediction of drought and its structure. In particular, prediction research has focused on the evaluation and improvement of prediction models. The modelling tools used are [[global climate model|global]] and regional climate models (GCMs and RCMs), and [[hydrological model|hydrological models]]. The hydrological models are driven by output from the [[atmospheric models]], data from ongoing research sites and reanalysis products. DRI modeling studies address the following questions: |
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Droughts tend to persist in that warm, dry springs are followed by hot, dry summers. There also appears to be a tendency for warm summers to follow other warm summers, and so on. Reasons for this are likely related to feedback processes that enhance or prolong drought situations (such as soil moisture anomalies) however, more research is required. |
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*How well was the current drought predicted based on current techniques? |
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*To what extent could this prediction be improved through better initialization? |
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*To what extent could this prediction be improved through dynamical [[downscaling]] and better [[physics]]? |
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*What are the appropriate scales and processes for prediction of Prairie droughts? |
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Use is being made of archived historical model outputs and new simulations to address many of these issues. DRI focuses on many facets of a particular extreme and consequently many more variables beyond the traditional temperature and precipitation need to be examined. For example, experiments carried out within DRI are helping to assess the role of [[soil moisture]] and [[snow cover]] on seasonal prediction. |
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===4: Drought Comparisons === |
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== Future Droughts == |
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Theme 4 provides comparisons of the recent drought and previous droughts over this region and those in other regions, in the context of [[climate variability]] and [[climate change|change]]. For many users there is a need to understand a current or recent drought event in the context of historical droughts. These comparisons are guided by the following research questions: |
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*How do the physical features, processes, and feedbacks of the recent Canadian Prairie drought compare with a) previous droughts over the [Drought in Canada|Canadian Prairies], b) [Drought in Canada|Canada-wide droughts]], c) [[Drought in the United States|US Great Plains droughts]], and d) [[drought|droughts across the world]]? |
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*How does the prediction of the recent drought compare with predictions of other droughts? |
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*How does the recent drought compare with past [[climate variability]] and projected [[climate change]]? |
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Comparisons between the 1999-2004/05 drought have focused on the internal structure of drought, as well as its presence over a particular region. Many droughts, including the 1999-2005 event have a complex internal structure for their precipitation patterns which often changed dramatically during the drought. More details on these comparisons are available in Bonsal (2008)<ref>Bonsal, B., 2008: Droughts in Canada: an overview. CMOS Bulletin, Vol. 36, No. 3, 79-86.</ref>. |
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===5: Drought Impacts === |
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In response to the economic and environmental significance of {drought|droughts]], scientific concern has been expressed regarding [[climate change]] impacts on future drought frequency, duration, and severity over various regions of the globe including Canada. [[Climate models]] are projecting considerable increases to temperature and in general, small increases to precipitation over southern Canada. This translates into future increases of summer continental interior drying and associated risk of droughts. The increased drought risk is attributed to a combination of increased temperature and [[potential evapotranspiration]] not being balanced by precipitation. Note that considerable uncertainty exists with respect to future precipitation, particularly on a regional basis. Furthermore, there is little consensus regarding future changes to [[teleconnection|teleconnections]] and since these patterns have a significant impact on temperature and precipitation over Canada, the occurrence of future drought remains a huge knowledge gap. |
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Theme 5 applies our progress in drought characterization and prediction to critical issues of importance to society during times of drought. These efforts are linked to the following questions: |
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== Monitoring and Prediction == |
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*What organizations are affected by drought? |
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*What exactly is the nature of their impact and how can this be alleviated? |
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*Given the progress being made by the Network, how can it address drought impacts on affected organizations? |
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In order to advance this theme, DRI has carried out an extensive consultative process with the users; has launched a set of simulation exercises to test how users may adapt new DRI products to make better decisions through an exercise known as DEWS (Drought Early Warning System test), and formed a Partners Advisory Committee composed of experts from user agencies and groups to give advice on their needs for DRI research and information. More details are available in Lawford et al. (2008)<ref>Lawford, R., H. Hill, E. Wheaton, I. Hanuta, A. Warkentin, B. Girling and R. Stewart, 2008: A review of some requirements for drought information on the Canadian Prairies. CMOS Bulletin, Vol. 36, No. 3, 97-102.</ref>. |
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== Program Structure and Linkages== |
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DRI is led by two Principal Investigators, Drs. Ronald Stewart and John Pomeroy. A Board of Directors, chaired by Jim Bruce oversees the program strategy and a Science Committee takes the day to day decisions about the implementation of the project. In addition, the operational details are implemented by a Secretariat consisting of a Network Manager, a Financial Manager and two Data Managers. A Partners Advisory Committee, chaired by Harvey Hill, also meets and reports on the user needs to the Board of Directors. The program have also established strong linkages and collaborations with research initiatives and departments and on provincial, federal and international levels. The detailed program structure and linkages can be found in Stewart et al., (2008)<ref name="Stewart"/>. |
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== The Dri Legacy == |
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Numerous indices that measure drought severity are used to monitor drought. These range from those that only consider [[precipitation]], to complex indices that incorporate a water balance approach using precipitation, antecedent [[soil moisture]], potential [[evapotranspiration]], and [[runoff]]. For Canada, real-time information on pasture conditions, on-farm surface water supplies, and several [[drought indices]] are provided in [[Agriculture and Agri-Food Canada|Agriculture and Agri-Food Canada's]] [http://www.agr.gc.ca/pfra/drought/article_e.htm Drought Watch] <ref>[http://www.agr.gc.ca/pfra/drought/article_e.htm Agriculture and Agri-Food Canada Drought Watch]</ref>web site. The site monitors the risk and status of drought over major agricultural regions of the country and also promotes practices to reduce drought vulnerability. The [http://www.ncdc.noaa.gov/oa/climate/monitoring/drought/nadm/ North American Drought Monitor] <ref>[http://www.ncdc.noaa.gov/oa/climate/monitoring/drought/nadm/ North American Drought Monitor]</ref> has been established as a cooperative effort among drought experts in Canada, Mexico, and the U.S. to monitor drought on a weekly basis. The site provides North American maps based on a synthesis of multiple indices and local impacts that best represents current drought conditions. |
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DRI has brought together an unprecedented amount of information on [[Drought in Canada|Canadian drought]]. On its [http://www.drinetwork.ca web site], one can find many links to various datasets that describe elements of drought in the atmosphere, at the surface or below the surface. Compiling a Prairie-wide database of provincial groundwater and water levels is part of this effort. The data are being brought together in an integrated information system. Synthesis articles, special issue of [[Atmosphere-Ocean]] and a public information document about the 1999-2005 drought are in preparation. In addition, new techniques of archiving and making available datasets are being explored as one other legacy of DRI. Undoubtedly, the greatest legacy of DRI will be the young people who have been trained at the PhD, Masters and early scientist level who carried out much of this research and are now pursuing lifetime careers in disciplines related to DRI. |
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Drought prediction involves anticipating climatic anomalies that produce unusually dry conditions for an extended period. [[Environment Canada]] produces three-month [[deterministic forecasting|deterministic]] temperature and precipitation forecasts for the ensuing 1-3, 2-4, 4-6, 7-9, and 10-12 month periods. The 1-3 and 2-4 month forecasts are based upon an ensemble of 40 model runs. [[Probabilistic forecasting|Probabilistic forecasts]], which give estimates of the probability that the seasonal mean will be above, near, or below normal are also provided for the 1-3 and 2-4 month periods. Forecasts for 4-6, 7-9 and 10-12 months are produced with a statistical method. The forecasts are updated on a monthly basis and posted on the Environment Canada [http://www.weatheroffice.gc.ca/saisons/index_e.html Seasonal Forecasts] <ref>[http://www.weatheroffice.gc.ca/saisons/index_e.html Environment Canada Seasonal Forecasts]</ref> website. |
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== |
==References == |
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Bonsal, B., 2008: Droughts in Canada: an overview. CMOS Bulletin, Vol. 36, No. 3, 79-86. |
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Lawford, R., H. Hill, E. Wheaton, I. Hanuta, A. Warkentin, B. Girling and R. Stewart, 2008: A review of some requirements for drought information on the Canadian Prairies. CMOS Bulletin, Vol. 36, No. 3, 97-102. |
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Phillips, D.W., 2002: The top ten Canadian weather stories for 2001. CMOS Bulletin, 30, 19-23. |
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Statistics Canada, 2003: Net Farm Income. Catalogue No. 21-010-XIE, Volume 2. Ottawa, Ontario. |
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Stewart, R., J. Pomeroy and R. Lawford, 2008: A Drought Research Initiative for the Canadian Prairies, CMOS Bulletin, Vol. 36, No. 3, 97-102. |
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<references /> |
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==External Links == |
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Adaptation involves adjusting to [[climate change]], [[Climate variability|variability]], and extremes to avoid or alleviate negative impacts and benefit from opportunities. Drought adaptations include short to long-term actions, programs, and polices implemented both during, and in advance of the drought to help reduce risks to human life, property, and productive capacity. Canadians have a great deal of experience in adapting to droughts, however, their strategies vary by sector and location. Areas with greater drought risks are often better prepared to deal with dry conditions. Drought adaptation decisions are made at a variety of levels ranging from individuals, to groups and institutions, to local and national governments. There are various adaptation processes or strategies including sharing and/or bearing the loss, modifying drought effects, research, education, behavioral changes, and avoidance. Adaptive measures include [[soil conservation|soil]] and [[water conservation]], improved [[irrigation]], the construction of infrastructure (wells, pipelines, reservoirs), and the exploration of [[groundwater]] supplies. The usefulness of these strategies varies with location, sector, and nature and timing of the drought. Better management responses may be made with improved drought monitoring and advanced prediction. Adjustments that occur after the drought are generally less effective compared to planned anticipatory adaptation. |
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*[http://www.drinetwork.ca The Drought Research Initiative] |
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== Key References == |
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*[http://www.cfcas.org Canadian Foundation for Climate and Atmospheric Sciences (CFCAS)] |
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Bonsal, B.R., Chakravarti, A.K. and Lawford, R.G. 1993. Teleconnections between north Pacific SST anomalies and growing season extended dry spells on the Canadian Prairies, International Journal of Climatology, 13, 865-878. |
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Bonsal, B.R., Shabbar, A. and Higuchi, K. 2001. Impacts of low frequency variability modes on Canadian winter temperature, International Journal of Climatology, 21, 95-108. |
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Bonsal, B.R. and Regier, M. 2007 Historical comparison of the 2001/2002 drought in the Canadian Prairies, Climate Research, 33, 229-242. |
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Brown, R.D. 2000. Northern Hemisphere snow cover variability and change, 1915-97, Journal of Climate, 13, 2339-2355. |
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Chipanshi, A.C., Findlater, K.M., Hadwen, T. and O’Brien, E.G. 2006. Analysis of consecutive droughts on the Canadian Prairies, Climate Research, 30, 175-187. |
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Maybank, J., Bonsal, B.R., Jones, K., Lawford, R.G., O’Brien, E.G., Ripley, E.A. and Wheaton, E. 1995. Drought as a natural disaster, Atmosphere-Ocean, 33, 195-222. |
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Meehl, G.A. and Stocker, T.F. 2007. Global Climate Projections, Chapter 10 in: Climate Change 2007: The Physical Science Basis, Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK, pp. 747-845. |
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Sauchyn, D.J. and Skinner, W.R. 2001. A proxy record of drought severity for the southwestern Canadian plains, Canadian Water Resources Journal, 26, 253-272. |
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Shabbar, A., Bonsal, B.R. and Khandekar, M. 1997. Canadian precipitation patterns associated with the Southern Oscillation, Journal of Climate, 10, 3016-3027. |
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Shabbar, A. and Khandekar, M. 1996. The impact of El Niño-Southern Oscillation on the temperature field over Canada, Atmosphere-Ocean, 34, 401-416. |
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Shabbar, A. and Skinner, W. 2004. Summer drought patterns in Canada and the relationships to global sea surface temperatures, Journal of Climate, 17, 2866-2880. |
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Wheaton, E., Wittrock, V., Kulshreshtha, S., Koshida, G., Grant, C., Chipanshi, A. and Bonsal, B.R. 2005. Lessons Learned from the Canadian Drought Years of 2001 and 2002: Synthesis Report, Agriculture and Agri-Food Canada, Saskatchewan Research Council Publication No. 11602-46E03, Saskatoon, SK. |
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Zhang, X., Harvey, K.D., Hogg, W.D. and Yuzyk, T.R. 2001. Trends in Canadian streamflow, Water Resources Research, 37, 987-998. |
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Zhang, X., Vincent, L.A., Hogg, W.D. and Niitsoo, A. 2000. Temperature and precipitation trends in Canada during the 20th century, Atmosphere-Ocean, 38, 395-429. |
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== External References == |
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<references/> |
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Revision as of 17:02, 3 July 2009
The Drought Research Initiative(DRI) has been established "to better understand the physical characteristics of and processes influencing Canadian Prairie droughts, and to contribute to their better prediction, through a focus on the recent severe drought that began in 1999 and largely ended in 2005" [1]. It is an interdisciplinary effort that involves 15 funded investigators from 6 Canadian universities and more than 20 collaborators from other universities and federal laboratories as well as partners from three provincial governments (Alberta, Manitoba and Saskatchewan).
DRI is achieving its objective by focusing on five complementary research themes, including quantification, understanding, prediction, comparisons with other droughts, and implications for society. Readers wishing more detail than is available in this entry should read Stewart et al (2008)[2] or explore the DRI website
Background
Drought is an anomaly within the atmospheric, surface and sub-surface cycling of water and energy, usually initiated through large to regional scale atmospheric processes, and enhanced and maintained through regional to local {earth's atmosphere|atmospheric]], surface hydrology, land surface and groundwater feedbacks that operate throughout the annual cycle. Droughts are a distinctive feature of the Canadian Prairies where the large scale atmospheric circulations are influenced by [Block (meteorology)|blocking] from intense orography to the west and long distances from all warm ocean-derived atmospheric water sources.
DRI addresses a mulit-year drought that began in 1999 with cessation of its atmospheric component in 2004/2005 and many of its hydrological components in 2005. It was the worst drought for at least a hundred years in parts of the Canadian Prairies. According to Phillips (2002)[3], for the western and central Canadian Prairies during 2001 and 2002, “… it was the worst of times. Even in the dust bowl of the 1930s, no single year between Medicine Hat, Kindersley and Saskatoon was drier than in 2001”. The drought affected agriculture, recreation, tourism, health, hydro-electricity, and forestry in the Prairies. Gross Domestic Product fell some $5.8 billion and employment losses exceeded 41,000 jobs for 2001 and 2002. This drought also contributed to a negative or zero net farm income for several provinces for the first time in 25 years (Statistics Canada, 2003[4]) with agricultural production over Canada dropping an estimated $3.6 billion in 2001/2002. Previously reliable water supplies such as streams, wetlands, dugouts, reservoirs, and groundwater were placed under stress and often failed. More details are available in Wheaton (2006).
Despite the enormous economic, environmental, and societal impacts of droughts, DRI is undertaking the first integrated drought research program of its kind in Canada with the hope being that the occurrence and nature of drought can be better anticipated on short and long term scales. From a longer-term perspective, this 5-year Network represents an essential step in better predicting droughts over Canada, their detailed structure and their impacts with increasing confidence and better assessing whether there will be a ‘drying of the continental interior’ in the future
Research Themes
DRI is achieving its objective by focusing on five complementary research themes, including quantification, understanding, and better prediction of a particular drought with funding primarily from the Canadian Foundation for Climate and Atmospheric Sciences (CFCAS). Comparisons with other droughts, and implications for society have been funded with additional direct and in-kind support coming from Environment Canada, Agriculture and Agri-Food Canada, Natural Resources Canada, Prairie Farm Rehabilitation Administration (PFRA), Saskatchewan Watershed Authority, Saskatchewan Research Council, Manitoba Water Stewardship and Manitoba Hydro.
1: Characterizing Drought
To characterize the drought of 1999-2005 DRI has been quantifying its atmospheric, hydrologic, and land-surface physical features at a variety of spatial and temporal scales. This analysis will be realized by addressing three focused questions:
- What variables are required to quantify the characteristics of this recent drought?
- What data sources and model outputs are available for quantification of these parameters?
- How do we characterize and “close the budgets” of water and energy over the Prairies? .
The analysis has involved the development of a four-dimensional assessment of the atmosphere during the drought over various temporal scales using a knowledge of temperature, humidity, geopotential height, wind, clouds, precipitation amount, and current weather. At the surface, the spatial and temporal characteristics of vegetative state (in terms of water stress) for major vegetation types (crops and boreal zones), soil moisture, stream network, river flows, lake levels, wetlands, depression storage, groundwater and sub-surface flows be assessed to determine when and where drought is occurring. Although this is a difficult task due to data gaps, and the complexity of the shallow undulations in the prairies topography, an analysis of in-situ data, satellitedata and model output now provides a comprehensive overview of the evolution of the drought.
2: Drought Processes
DRI is also focusing on the understanding of the processes and feedbacks governing the formation, evolution, cessation and structure of the drought. This theme addresses the following questions:
- What processes were responsible for the onset of the recent drought?
- What processes and feedbacks contributed to the drought’s evolution, persistence, and spatial structure?
- What processes and feedbacks controlled the termination of this drought?
There are many ways in which drought, basically a sustained precipitation deficit, can be initiated and prolonged. Some processes that reduce precipitation include, large scale circulation anomalies, lack of moisture advected into a region, reduction of local moisture supplies, production of virga as opposed to precipitation, and possibly even the role of aerosols in the dusty environment acting to reduce precipitation. Over the five years of this drought, these processes and numerous other factors were operating at various times and locations to preclude substantial precipitation from being produced over large regions of the Prairies.
While prairie drought processes have characteristic spatial and temporal scales, land surface hydrological/biophysical processes generally operate at small spatial scales (and with larger inherent spatial variability) while atmospheric process have a hierarchy of scales ranging from planetary to local turbulence. DRI is addressing the cascade of energy and movement of moisture through atmospheric processes and the horizontal scale link between land surface and groundwater processes during drought events.
3: Drought Prediction
Drought prediction research in DRI is directed at assessing and reducing uncertainties in the prediction of drought and its structure. In particular, prediction research has focused on the evaluation and improvement of prediction models. The modelling tools used are global and regional climate models (GCMs and RCMs), and hydrological models. The hydrological models are driven by output from the atmospheric models, data from ongoing research sites and reanalysis products. DRI modeling studies address the following questions:
- How well was the current drought predicted based on current techniques?
- To what extent could this prediction be improved through better initialization?
- To what extent could this prediction be improved through dynamical downscaling and better physics?
- What are the appropriate scales and processes for prediction of Prairie droughts?
Use is being made of archived historical model outputs and new simulations to address many of these issues. DRI focuses on many facets of a particular extreme and consequently many more variables beyond the traditional temperature and precipitation need to be examined. For example, experiments carried out within DRI are helping to assess the role of soil moisture and snow cover on seasonal prediction.
4: Drought Comparisons
Theme 4 provides comparisons of the recent drought and previous droughts over this region and those in other regions, in the context of climate variability and change. For many users there is a need to understand a current or recent drought event in the context of historical droughts. These comparisons are guided by the following research questions:
- How do the physical features, processes, and feedbacks of the recent Canadian Prairie drought compare with a) previous droughts over the [Drought in Canada|Canadian Prairies], b) [Drought in Canada|Canada-wide droughts]], c) US Great Plains droughts, and d) droughts across the world?
- How does the prediction of the recent drought compare with predictions of other droughts?
- How does the recent drought compare with past climate variability and projected climate change?
Comparisons between the 1999-2004/05 drought have focused on the internal structure of drought, as well as its presence over a particular region. Many droughts, including the 1999-2005 event have a complex internal structure for their precipitation patterns which often changed dramatically during the drought. More details on these comparisons are available in Bonsal (2008)[5].
5: Drought Impacts
Theme 5 applies our progress in drought characterization and prediction to critical issues of importance to society during times of drought. These efforts are linked to the following questions:
- What organizations are affected by drought?
- What exactly is the nature of their impact and how can this be alleviated?
- Given the progress being made by the Network, how can it address drought impacts on affected organizations?
In order to advance this theme, DRI has carried out an extensive consultative process with the users; has launched a set of simulation exercises to test how users may adapt new DRI products to make better decisions through an exercise known as DEWS (Drought Early Warning System test), and formed a Partners Advisory Committee composed of experts from user agencies and groups to give advice on their needs for DRI research and information. More details are available in Lawford et al. (2008)[6].
Program Structure and Linkages
DRI is led by two Principal Investigators, Drs. Ronald Stewart and John Pomeroy. A Board of Directors, chaired by Jim Bruce oversees the program strategy and a Science Committee takes the day to day decisions about the implementation of the project. In addition, the operational details are implemented by a Secretariat consisting of a Network Manager, a Financial Manager and two Data Managers. A Partners Advisory Committee, chaired by Harvey Hill, also meets and reports on the user needs to the Board of Directors. The program have also established strong linkages and collaborations with research initiatives and departments and on provincial, federal and international levels. The detailed program structure and linkages can be found in Stewart et al., (2008)[2].
The Dri Legacy
DRI has brought together an unprecedented amount of information on Canadian drought. On its web site, one can find many links to various datasets that describe elements of drought in the atmosphere, at the surface or below the surface. Compiling a Prairie-wide database of provincial groundwater and water levels is part of this effort. The data are being brought together in an integrated information system. Synthesis articles, special issue of Atmosphere-Ocean and a public information document about the 1999-2005 drought are in preparation. In addition, new techniques of archiving and making available datasets are being explored as one other legacy of DRI. Undoubtedly, the greatest legacy of DRI will be the young people who have been trained at the PhD, Masters and early scientist level who carried out much of this research and are now pursuing lifetime careers in disciplines related to DRI.
References
Bonsal, B., 2008: Droughts in Canada: an overview. CMOS Bulletin, Vol. 36, No. 3, 79-86. Lawford, R., H. Hill, E. Wheaton, I. Hanuta, A. Warkentin, B. Girling and R. Stewart, 2008: A review of some requirements for drought information on the Canadian Prairies. CMOS Bulletin, Vol. 36, No. 3, 97-102. Phillips, D.W., 2002: The top ten Canadian weather stories for 2001. CMOS Bulletin, 30, 19-23. Statistics Canada, 2003: Net Farm Income. Catalogue No. 21-010-XIE, Volume 2. Ottawa, Ontario. Stewart, R., J. Pomeroy and R. Lawford, 2008: A Drought Research Initiative for the Canadian Prairies, CMOS Bulletin, Vol. 36, No. 3, 97-102.
- ^ Drought Research Initiative Mission Statement
- ^ a b Stewart, R., J. Pomeroy and R. Lawford, 2008: A Drought Research Initiative for the Canadian Prairies, CMOS Bulletin, Vol. 36, No. 3, 97-102.
- ^ Phillips, D.W., 2002: The top ten Canadian weather stories for 2001. CMOS Bulletin, 30, 19-23.
- ^ Statistics Canada, 2003: Net Farm Income. Catalogue No. 21-010-XIE, Volume 2. Ottawa, Ontario.
- ^ Bonsal, B., 2008: Droughts in Canada: an overview. CMOS Bulletin, Vol. 36, No. 3, 79-86.
- ^ Lawford, R., H. Hill, E. Wheaton, I. Hanuta, A. Warkentin, B. Girling and R. Stewart, 2008: A review of some requirements for drought information on the Canadian Prairies. CMOS Bulletin, Vol. 36, No. 3, 97-102.