Toward a Better Understanding of Hydrological Impacts of Climate Change: Lessons Learned from Ouranos Hydroclimatic Studies Based on Regional Climate Model Simulations

English Abstract:

Global warming is expected to alter the water cycle across the planet in multiple ways. Many studies indicate that hydrological regimes and extremes across different regions of the world will be affected differently bringing about various unfamiliar environmental risks. Understanding regional hydrological cycles and their variability and potential changes under an evolving climate requires the development and implementation of sophisticated modeling and data analysis tools. Numerical climate change experiments based on Regional Climate Model (RCMs) have proven to be powerful tools in assessing hydrological impacts of climate change over a region of interest. Constantly refining spatial resolution of RCMs promises better representation of small-scale processes and more reliable description of the interactions between the land-surface and the atmosphere, which have significant effects on the hydrological cycle. In the past years, the Ouranos Climate Simulation and Analysis team has produced a large number of regional climate simulations using the Canadian RCM (CRCM) at a spatial resolution of 45 km. Data from this vast databank has been very useful for hydrological impact and adaptation studies. Moreover, RCM simulations generated in the framework of several international collaborative RCM projects, such as NARCCAP, in which Ouranos made significant contributions, allowed construction of multi-model ensembles that are essential for analysis and quantification of various sources of uncertainties. Quantifying uncertainty associated with RCM simulations is an important part of hydrological projections and will be discussed in the first part of the presentation. Thereupon, several results where RCM hydrological outputs are used to assess impact of climate change on the probability of extreme events of the hydrological regime will be presented. Special focus will be given to projects aiming to assess Great Lakes Net Basin Supplies under a changing climate.