Constructing Intensity-Duration-Frequency Curves Under Changing Climate in Canada Using CMIP5 and CMIP6 Climate Simulations

Global warming is a worldwide growing threat induced by human activities since late 19th century. One of the consequences of increasing air temperature is the augmentation of the atmosphere's water holding capacity and acceleration of evaporation, which affect formation of extreme rainfalls and their spatial and temporal distributions. Specifically, extreme rainfalls are becoming more intense and frequent in many regions of the world. Canada is not an exception as global warming is expected to be more severe than the global average. Larger amounts of annual rainfalls are already observed, accompanied with intensifications of extreme rainfall events. As the population is growing in the country, particularly in the cities, they become more vulnerable to extreme rainfall disasters such as urban flooding. The Intensity-Duration-Frequency (IDF) curves are typically used by engineers to statistically estimate the characteristics of extreme rainfall at a given location. The historical characteristics of IDF curves are often used for design and maintenance of various urban infrastructures. However, changes in climate can modify the IDF curves in Canadian cities. Therefore, it is urgent to update the IDF curves accounting projected precipitation to ensure the safety of future projects and lessen the vulnerability of the urban population. Moreover, these extreme events lead to increasing compensation and repair costs in the regions.