Étude d'un réseau socio-technique menant à la création d'un objet nouveau : le cas de la radio numérique à la Société Radio-Canada

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Hydrological Modeling of the Tampaon River in the Context of Climate Change

This work compares the hydrological modeling of the Tampaon River Basin (in east-central Mexico) with two hydrological models (SWAT and GR4J) and then evaluates the impact of climate change on the water balance of the basin. The calibration and validation of the models (over 14-year periods) show that both performed satisfactorily when simulating daily flows. The results indicate that SWAT more precisely reproduces observed mean monthly streamflow while GR4J overestimates it during the dry season and underestimates it during the rainy season. The analysis of the impact of climate change was performed by using climate ensemble simulations derived from the Canadian Global Climate Model (CGCM3) downscaled by the Canadian Regional Climate Model (CRCM). The climate simulations (after bias correction) were used as input data for both hydrological models for two periods: a reference period (1971 – 2000) and a future period (2041-2070). The results indicate a significant decrease in mean monthly streamflow in the Tampaon River Basin for the future period (-36 to -55%), as well as a decrease in maximum monthly streamflow (-34 to -60%) and minimum monthly streamflow (-36 to -49%). The results from this study provide an overall perspective of the potential impact of climate change on the hydrological response of the Tampaon River Basin

Reply to “Comments on ‘The North American Regional Climate Change Assessment Program: Overview of Phase I Results\u27”

The authors of Mearns et al. (2012) are aware of the role of driving RCMs with reanalyses and have written extensively on the roles of different types of regional climate models (RCMs) simulations (e.g., Giorgi and Mearns 1999; Leung et al. 2003). Thus, we agree that the skill of dynamical downscaling in which global reanalysis is used to provide boundary conditions in general indicates an upper bound of skill compared to dynamical downscaling in which the boundary conditions come from global climate model simulations. This finding has long been established, as global climate model simulations cannot outperform global reanalysis in providing boundary conditions since the latter is constrained by observations through data assimilation (that is, unless the reanalyses themselves have been shown to have serious deficiences; e.g., Cerezo-Mota et al 2011). The classification of different types of dynamical downscaling introduced by Castro et al. (2005) further adds clarity to this point

Construction de projections hydro-climatiques et leurs incertitudes associées à partir de simulations issues de modèles régionaux de climat : Application à la gestion des eaux des réservoirs hydroélectriques du Québec

Construction of hydro-climatic projections and first-order estimation of their associated uncertainties from Regional Climate Model simulations : Application to water management of hydropower reservoirs in Quebec. This paper outlines the steps followed to construct hydro-climatic projections of basin-scale runoff and their associated uncertainties over the Québec/ Labrador peninsula. First, we show that the physically-based Canadian RCM (Regional Climate Model) is able to reproduce basin-scale annual runoff within observational errors. The robustness of the CRCM at simulating annual runoff at the basin scale is studied through an analysis of the model’s intrinsic internal noise (e. g., internal variability related to the non-deterministic nature of the climate system), which we find to be small (with respect to observational errors and interannual variability of observed runoff). The CRCM’s main advantage is that it is constructed with balanced land and atmosphere water and energy budgets, and includes feedbacks between the surface and the atmosphere ; providing variables that are all internally consistent. However, due to weaknesses in the representation of snow and land-surface processes in CLASS 2.7, the simulated intra-annual runoff is not adequately reproduced. Sensitivity experiments show that domain size has an important effect on simulated annual runoff, and that surface scheme and driving reanalyses have less influence but still remain significant. These findings imply that not only should the experimental configuration of a simulation be carefully defined according to the area of interest, but also that one must consider results from more than just a single RCM simulation (to account for the model’s internal variability). Following these basic steps, more trustworthy climate change data can be provided to water resource managers. Through the provision of an ensemble of regional climate projections, it is then possible to evaluate the climate change signal and the associated level of confidence.Cet article donne un aperçu des étapes suivies pour construire des projections hydro-climatiques d’écoulement à l’échelle des bassins versants sur la péninsule Québec/ Labrador, avec les incertitudes qui y sont associées. Dans un premier temps, nous montrons que le Modèle régional canadien du climat (MRCC) est capable de reproduire l’écoulement annuel aux bassins à l’intérieur des erreurs d’observation. L’habileté du MRCC à simuler l’écoulement annuel à l’échelle des bassins est étudiée à travers l’analyse du bruit interne intrinsèque au modèle (i. e., variabilité interne reliée à la nature non déterministe du système climatique), que nous trouvons petit (par rapport aux erreurs d’observation et à la variabilité inter-annuelle de l’écoulement observé). L’avantage principal du MRCC réside dans sa base physique car il respecte des bilans équilibrés d’eau et d’énergie, il inclut les rétroactions entre la surface et l’atmosphère, générant des variables qui sont physiquement cohérentes entre elles. Toutefois, quelques faiblesses dans la représentation des processus de neige et du sol de CLASS 2.7 font en sorte que l’écoulement intra-annuel simulé n’est pas adéquat. Nos expériences de sensibilité montrent que la dimension du domaine a un effet important sur l’écoulement annuel simulé. Le schéma de surface et les réanalyses qui pilotent le MRCC ont moins d’influence mais demeurent significatifs. Ces résultats impliquent qu’il faudrait non seulement définir soigneusement la configuration expérimentale d’une simulation selon la région d’intérêt mais également considérer plus d’une simulation MRC (pour tenir compte de la variabilité interne du modèle). En suivant ces étapes, les gestionnaires des réservoirs hydro-électriques peuvent obtenir des valeurs de changement climatique plus fiables. En fournissant un ensemble de projections climatiques régionales, il est alors possible d’évaluer le signal du changement climatique ainsi que le niveau de confiance qui y est associé.Frigon Anne, Slivitzky Michel, Caya Daniel, Roy René. Construction de projections hydro-climatiques et leurs incertitudes associées à partir de simulations issues de modèles régionaux de climat : Application à la gestion des eaux des réservoirs hydroélectriques du Québec. In: Variations climatiques et hydrologie. Le climat, ses variations séculaires et ses changements pronostiqués : quel impact sur l'hydrologie (ressources en eau et évènements rares, étiages - crues). 29èmes Journées de l'Hydraulique. Congrès de la Société Hydrotechnique de France. Lyon, 27-28 mars 2007. 2007

Implementation of a large-scale variable velocity flow routing algorithm in the Canadian Regional Climate Model (CRCM

ABSTRACT Implementation and validation of a flow routing scheme for the North American domain of the Canadian Regional Climate Model (CRCM) is described. A variable velocity flow routing algorithm is used to transport runoff from the land surface to the continental edges and provide freshwater flux forcing for the oceans. The flow routing scheme uses Manning’s equation to estimate flow velocities for river channels whose cross-sections are assumed to be rectangular. Discretization of major North American river basins and their flow directions are obtained at the polar stereographic resolution of the CRCM using 5-minute global river flow direction data as a template. In the absence of observation-based gridded estimates of runoff, model runoff estimates from a global simulation of the Variable Infiltration Capacity (VIC) hydrological model (forced with observationbased meteorological data) are used to validate the flow routing scheme. Model results show that the inclusion of flow routing improves the comparison with observation-based streamflow estimates when compared to the unrouted runoff. Monthly comparison of simulated streamflow with observation-based estimates, and basin-wide averaged flow velocities, suggests that the flow routing scheme performs satisfactorily. RÉSUME [Traduit par la rédaction] L’article décrit la mise en œuvre et la validation d’un schéma de routage du ruissellement pour le domaine nord-américain du Modèle régional canadien du climat (MRCC). Un algorithme de routage du ruissellement à vitesse variable est utilisé pour simuler le transport du ruissellement à la surfac

Hydrological response to dynamical downscaling of climate model outputs: A case study for western and eastern snowmelt-dominated Canada catchments

Study region: An analysis of hydrological response to a dynamically downscaled multi-member multi-model global climate model (GCM) ensemble of simulations based on the Canadian Regional Climate Model (CRCM) is presented for three snowmelt-dominated basins in Canada. The basins are situated in the western mountainous (British Columbia) and eastern level (Quebec) regions in Canada, providing comprehensive experiments to validate the CRCM over various topographic features. Study focus: The evaluation of the CRCM as a tool to improve GCM simulations of catchment scale hydrology is investigated within the bounds of uncertainty associated with RCM simulations. Daily climate variables were extracted from a 30-year CRCM and GCM ensemble simulations. The hydrological response was assessed through the comparison of catchment water components simulated by SWAT. New hydrological insights for the region: Results show that the CRCM captures the primary features of observed climate, but there are significant biases. Most noteworthy are a positive bias in precipitation and a negative bias in temperature over the BC basin. When looking at the hydrological modeling results, the benefit of using the RCM versus GCMs emerged distinctly for the mountainous BC basin where the RCM is preferred over the GCMs. The sensitivity experiments show that uncertainty in the GCM/RCM’s internal variability must be assessed to provide suitable regional hydrological responses to climate change

Incorporating river routing in the Canadian Regional Climate Model

m et al. (1999) discretized 10 major river basins over North America and the discretization of these river basins at the CRCM resolution is shown in Fig. 1. The drainage areas of the major river basins at the CRCM resolution are compared with drainage areas based on 5' discretization of Graham et al. (1999) in Table 1. Table 1: Comparison of drainage areas of river basins discretized at the CRCM resolution with drainage areas based on 5' discretization of Graham et al. (1999). River Basin Drainage area (km ) Percentage Graham et al. CRCM Difference Mississippi 3,218,720 3,228,415 0.30 Mackenzie 1,735,635 1,748,230 0.73 Nelson 1,303,641 1,305,674 0.16 Columbia 1,106,969 1,106,439-0.05 St-Lawrence 1,090,564 1,087,952-0.24 Yukon 884,867 882,128-0.31 Rio Grande* 856,547 149,144-82.59 Colorado* 770,829 616,827-19.98 Churchill 296,190 300,800 1.56 Fraser 262,854 260,419-0.93 *The CRCM drainage areas for Colorado and Rio Grande do not compare well with Graham et al. (1999) va