Projected increases in intensity and frequency of rainfall extremes through a regional climate modeling approach

Abstract

Global warming is changing the hydrological cycle in multiple ways such as increased cloudiness, latent heat fluxes, and intense precipitation events. How extreme rainfall events will be influenced by the changing climate is becoming one of the most important problems for hydrological risk analysis and engineering design. In this study, a regional climate modeling approach based on the Providing REgional Climates for Impacts Studies modeling system is proposed for investigating the potential impacts of climate change induced by increased greenhouse gases on the intensity and frequency of extreme rainfall events in the context of Ontario, Canada. An ensemble of high-resolution climate projections is first developed under both current and future forcing conditions. Validation of the ensemble simulations is then conducted through comparing the simulated rainfall annual extremes for 1960-1990 to the observed ones. Following that, the rainfall projections for future periods are used to develop projected intensity-duration-frequency curves and their plausible changes in 2030s, 2050s, and 2080s for the City of Toronto. The results suggest that intensities of rainfall extreme events versus various durations with different return periods are all likely to increase over time: [5, 17]% in 2030s, [11, 22]% in 2050s, and [25, 50]% in 2080s. Such a consistent increase would lead to an overall uplift in the exceedance values of rainfall intensity of extreme events, implying that intense rainfall events are likely to occur more frequently in the future. In addition, more significant changes in the rainfall intensity are projected for extreme events with longer return periods at all given durations.

Investigating future precipitation changes over China through a high‐resolution regional climate model ensemble

“…Besides, RCMs also have similar physical processes and mechanisms as described in GCMs, so the results simulated by dynamical downscaling techniques are closer to reality. Given their benefits, dynamical downscaling techniques are popular for climate simulations and projections [En-Tao et al, 2010;Carvalho et al, 2011;Wang et al, 2014aWang et al, , 2014bWang et al, , 2015Wang et al, 2016].…”

Future Changes in Precipitation Extremes Over Canada: Driving Factors and Inherent Mechanism

“…Changes in circulation could affect precipitation changes through dynamic effects of a strong positive feedback between circulation and convection on moisture convergence (Ma & Xie, ; Seager et al, ). This will eventually result in increased precipitation and more frequent precipitation extremes in extratropical regions (Betts, ; He, ; Held & Soden, ; Wang, Huang, & Liu, ).…”

The Need for an Integrated Land‐Lake‐Atmosphere Modeling System, Exemplified by North America's Great Lakes Region

“…Increased precipitation extremes from summer convective storms and winter lake effect storms have also inflicted unprecedented infrastructure damage and economic losses in the Great Lakes megaregion, for example, summer urban flooding in Toronto in 2013 cost more than CA$ 900 M (Wang et al, ). These types of changes are expected to substantially increase infrastructure damage in major cities across the United States (Ntelekos et al, ).…”