Abstract This case study concerns a major flood event occurred in July 1996 in the Saguenay region (Québec, Canada) induced by heavy and persistent rainfall over this river basin. Various configurations of the CRCM6/GEM5 regional climate model (RCM) using 12-km (0.11° x 0.11°) and convection-permitting (CP) 2.5-km (0.0225° x 0.0225°) resolutions are used to evaluate added value from CP simulations on the simulated extreme precipitation characteristics. The effects of spectral nudging (SN) and initial soil moisture conditions (ISMCs) on surface are also tested on the simulated rainfall. The evaluation of all simulations shows a significant improvement in reproducing precipitation extremes with the convection-permitting model (CPM) at 2.5-km, and substantial influences from SN, and ISMCs. The SN in the CP simulation improved the spatial and temporal patterns of precipitation extremes. Additionally, forced ISMC from a long-term simulations at a 12-km resolution significantly enhanced the model’s ability to capture rainfall intensity, using rainfall observed stations as a reference dataset. This research contributes to the understanding of extreme precipitation events and its reliability as simulated by various configurations of our RCM, and the need to apply higher resolution and accurate surface conditions in the CRCM6/GEM5 for future projections, and its use in design infrastructures, and flood risk management strategies.
Ghosh et al. (Fri,) studied this question.