Climate change impacts on the hydrologic regime of a Canadian river: comparing uncertainties arising from climate natural variability and lumped hydrological model structures

Abstract

Abstract. Diagnosing the impacts of climate change on water resources is a difficult task pertaining to the uncertainties arising from the different modelling steps. Lumped hydrological model structures contribute to this uncertainty as well as the natural climate variability, illustrated by several members from the same Global Circulation Model. In this paper, the hydroclimatic modelling chain consists of twenty-four potential evapotranspiration formulations, twenty lumped conceptual hydrological models, and seven snowmelt modules. These structures are applied on a natural Canadian subcatchment to address related uncertainties and compare them to the natural internal variability of simulated climate system as depicted by five climatic members. Uncertainty in simulated streamflow under current and projected climates is assessed. They rely on interannual hydrographs and hydrological indicators analysis. Results show that natural climate variability is the major source of uncertainty, followed by potential evapotranspiration formulations and hydrological models. The selected snowmelt modules, however, do not contribute much to the uncertainty. The analysis also illustrates that the streamflow simulation over the current climate period is already conditioned by the tools' selection. This uncertainty is propagated to reference simulations and future projections, amplified by climatic members. These findings demonstrate the importance of opting for several climatic members to encompass the important uncertainty related to the climate natural variability, but also of selecting multiple modelling tools to provide a trustworthy diagnosis of the impacts of climate change on water resources.

An assessment of the possible impacts of climate change on snow and peak river flows across Britain

“…Ficklin et al (2014) indicate that uncertainty in snowmelt model parameters can lead to statistically significant differences in hydrological climate change projections. However, Seiller and Anctil (2014) show that, for a catchment in Canada, the snow module is a much smaller source of uncertainty than hydrological model structure, PE formulation and natural variability. Studies looking at PE estimation using climate model data have shown that it can be an important source of uncertainty ) but accounting for the influence of higher carbon dioxide concentrations on plant stomata, as here, can reduce the future PE increases that may otherwise be expected (Bell et al 2011;Rudd and Kay 2016).…”

Summer Season Water Temperature Modeling under the Climate Change: Case Study for Fourchue River, Quebec, Canada

“…It has shown good results in Canada [47][48], especially, it has produced relatively good flow and water temperature simulations for the Fourchue River [40], which is the study area. The CEQUEAU model is a semi-distributed hydrologic model which takes into account the hydro-physiographic characteristics of the basin [49].…”

Use of very high resolution climate model data for hydrological modelling: estimation of potential evaporation

“…Many formulae exist for estimating PE, ranging from the physically-based Penman-Monteith formula (Monteith 1965) to much simpler empirical formulae like that of Oudin et al (2005), and the choice can affect the results of subsequent hydrological modelling (e.g. Seiller andAnctil 2014, Kay andDavies 2008). There is much disagreement on the best approach when deriving PE from climate model data for future periods, with concerns about empirical formulae not explicitly including changes in all the influencing variables, but also concerns about data quality when using more complex formulae (see discussion of Kay et al 2013).…”