Heavy precipitation events in the Mediterranean: sensitivity to cloud physics parameterisation uncertainties

Ensemble predictions based on cloud physics parameterization uncertainties show variable effectiveness depending on the meteorological scenario, with multi-process perturbations offering greater potential at higher model resolutions. The study used the Meso-NH model to investigate heavy precipitation events in southeastern France, comparing two contrasting cases: one associated with a warm, moist flow over the Cévennes ridge and another involving a quasi-stationary meso-scale convective complex over the Rhone valley. While the former case demonstrated higher forecast skill and minimal sensitivity to microphysical perturbations, the latter showed that multi-process perturbations could modulate rainfall intensities more effectively than localization, particularly when model resolution was increased to 500 m. These findings highlight the importance of tailored ensemble strategies for improving predictions in data-scarce regions like the UNESCO-listed Causses and Cévennes landscape.

Fresnay, S., Hally, A., Garnaud, C., Richard, E., & Lambert, D. (2012). Heavy precipitation events in the Mediterranean: sensitivity to cloud physics parameterisation uncertainties. Natural Hazards and Earth System Sciences, 12(8), 2671–2688. https://doi.org/10.5194/nhess-12-2671-2012