Canadian Regional Climate Model as a Tool for Assessing Hydrological Impacts of Climate Change at the Watershed Scale
Recent impact studies indicate that water resources in many regions of the world can be strongly affected by climate change. Different approaches and techniques have been developed to assess the hydrological impacts at different scales. The first part of
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Abstract
Recent impact studies indicate that water resources in many regions of the world can be strongly affected by climate change. Different approaches and techniques have been developed to assess the hydrological impacts at different scales. The first part of this chapter is an overview of the techniques designed to evaluate global warming effects on runoff, which can be considered as a measure of water availability. The advantages and shortcomings of these techniques are briefly discussed. The second part focuses on direct use of climate-model runoff for hydrological impact studies. Uncertainties associated with this approach are discussed, and some of them are assessed by comparing hydrological balance components for several watersheds in western North America simulated by the Canadian GCM and the Canadian RCM.
Introduction Numerical modeling is a commonly accepted approach for assessing climate change impacts on hydrological regimes at various scales. The following modeling tools/techniques are normally used: Global Climate Models (GCMs), Regional Climate Models (RCMs), statistical downscaling techniques, and hydrological models (HM). Global Climate Models simulate future climate under assumed greenhouse gas emission scenarios. As these models have a coarse spatial resolution, application of downscaling techniques is
B. Music (*) Ouranos, Consortium sur la climatologie re´gionale et l’adaptation aux changements climatiques, Montre´al, QC, Canada Centre ESCER, Universite´ du Que´bec a` Montre´al, Montre´al, QC, Canada e-mail: [email protected]
required to provide information at regional/local scale. Downscaling of GCM large-scale variables involves application of RCMs and/or statistical downscaling techniques. An overview of various methods used to assess hydrological impacts of climate change at the watershed scale is given in section “Methods for Evaluation of a Watershed Hydrological Response to Global Climate Change.” Some advantages and shortcomings of these approaches are also discussed. The second part of this study explores the opportunity of directly using climate-model runoff for hydrological impact studies. Water budget components simulated by the Canadian Global Climate Model (CGCM, Flato and Boer 2001; Scinocca et al. 2008) and the Canadian Regional Climate Model (CRCM, Caya and Laprise 1999; Plummer et al. 2006; Music and Caya 2007) for several watersheds in western North America (Columbia, Fraser, Upper Peace, and Campbell) are investigated. These watersheds covered by the CRCM and CGCM computational grids are
A. Berger et al. (eds.), Climate Change, DOI 10.1007/978-3-7091-0973-1_12, # Springer-Verlag Wien 2012
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Fig. 1 Western North America with the Columbia, Fraser, Upper Peace, and Campbell watersheds outlined
presented in Fig. 1. Columbia and Fraser outlines are taken from US Geological Survey, while Upper Peace and Campbell watersheds are defined by BC Hydro. Information about expected hydrological impacts of climate change at the watershed scale is of great interest a
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