High-Resolution Modeling of Extreme Heat in Urban Areas in Canada

According to the statistic analysis of data from CMIP5 (Coupled Model Intercomparison Project - Phase 5), the average number of heat-waves days in summer will increase in the future over urban areas following the climate projection scenarios (e.g. SSP2- 4.5 and SS P 5- 8.5).

In 2010 and 2018, heat-waves have caused several (106 and 90, respectively) deaths in Quebec, Canada, during the summers because the maximum temperatures exceeded 32°C on a period of three consecutive days. Environment and Climate Change Canada (ECCC) provides Numerical Weather Prediction (NWP) at the urban scale with the Town Energy Balance (TEB) model coupled with the Global Environmental Multiscale (GEM) atmospheric model. These systems are capable of providing forecasts of meteorological conditions and thermal stress indices (such as UTCI, WBGT, and Humidex) at the street level. As a control simulations, the warm conditions are simulated at high-resolutions (250 m and 100 m) over Montreal and Toronto metropolitan areas. Afterwards, different scenarios with modifications of the urban landscape are analyzed in order to provide decision-making guidance.

Results reveal that some management strategies in cities can decrease the impact of extreme heat conditions, such as modifications of radiative and materials properties, greening strategies, water management and anthropogenic heat fluxes.