The ClimEx Project: A 50-Member Ensemble of Climate Change Projections at 12-km Resolution over Europe and Northeastern North America with the Canadian Regional Climate Model (CRCM5)

Abstract

The Canadian Regional Climate Model (CRCM5) Large Ensemble (CRCM5-LE) consists of a dynamically downscaled version of the CanESM2 50-member initial-conditions ensemble (CanESM2-LE). The downscaling was performed at 12-km resolution over two domains, Europe (EU) and northeastern North America (NNA), and the simulations extend from 1950 to 2099, following the RCP8.5 scenario. In terms of validation, warm biases are found over the EU and NNA domains during summer, whereas during winter cold and warm biases appear over EU and NNA, respectively. For precipitation, simulations are generally wetter than the observations but slight dry biases also occur in summer. Climate change projections for 2080–99 (relative to 2000–19) show temperature changes reaching 8°C in summer over some parts of Europe, and exceeding 12°C in northern Québec during winter. For precipitation, central Europe will become much dryer during summer (−2 mm day−1) and wetter during winter (>1.2 mm day−1). Similar changes are observed over NNA, although summer drying is not as prominent. Projected changes in temperature interannual variability were also investigated, generally showing increasing and decreasing variability during summer and winter, respectively. Temperature variability is found to increase by more than 70% in some parts of central Europe during summer and to increase by 80% in the northernmost part of Québec during the month of May as the snow cover becomes subject to high year-to-year variability in the future. Finally, CanESM2-LE and CRCM5-LE are compared with respect to extreme precipitation, showing evidence that the higher resolution of CRCM5-LE allows a more realistic representation of local extremes, especially over coastal and mountainous regions.

How Daily Temperature and Precipitation Distributions Evolve With Global Surface Temperature.

“…For higher warming levels, the precipitation change over land is generally positive and present an increase per degree of warming, consistent with expectations (Allen & Ingram, ). An interesting exception is summertime precipitation over Europe, which indicates a marked drying (−5% for a 3‐degree global warming) that has also long been a feature of climate models (Leduc et al, ; Manabe & Wetherald, ; Rowell & Jones, ; Vautard et al, ). A similar feature is visible for South America for the same (boreal) season, also consistent with observations and model projections (Erfanian et al, ; Neelin et al, ).…”

Projected Changes in the Probability Distributions, Seasonality, and Spatiotemporal Scaling of Daily and Subdaily Extreme Precipitation Simulated by a 50‐Member Ensemble Over Northeastern North America

“…A spin up period of four years was discarded for each CRCM5-LE member series, resulting in 146 years of hourly precipitation available at 280×280 grid points over the 1954-2099 period. The reader can refer to Leduc et al (2019) for additional details on the experimental setup and validation of CRCM5-LE monthly temperature and precipitation statistics. Innocenti et al (2019) evaluated the Canadian RCM performances in representing the extreme rainfall characteristics (including diurnal and annual cycles) at several spatiotemporal scales by comparing CRCM5 simulations driven by the ERA-Interim reanalysis (Dee et al, 2011) to other simulated and observational gridded dataset.…”

Impact of internal variability on climate change for the upcoming decades: analysis of the CanESM2-LE and CESM-LE large ensembles

“…It would also be relevant to compare the current likelihood of linear, accelerating, or decelerating rate of change with other large ensembles, ideally with a lower climate sensitivity or another RCP, as such products are becoming more available. Finally, a continuation of this work could be to explore how recent regional model large ensembles, namely CanESM2-CRCM5 (ClimEx; Leduc et al (2019)) and CanESM2-CanRCM4, compare with the driving model CanESM2-LE.…”