A statistical downscaling to identify the large‐scale circulation patterns associated with heavy precipitation events over southern France

Heavy precipitation events (HPEs) over southern France are strongly linked to specific large-scale circulation patterns, particularly a deep upper-level low northwest of the region that induces a southerly flow. This study identifies four robust clusters of atmospheric conditions, with one cluster showing a 70% success rate in predicting HPEs when using synoptic-scale parameters alone. Further refinement reveals that moisture transport direction and intensity—south-southeasterly flows for Cévennes events and easterly winds with dual moisture streams for Languedoc-Roussillon events—are critical factors. The research combines ECMWF ERA-40 reanalysis data with local rain-gauge observations to statistically downscale and characterize these patterns, offering a tool for better HPE prediction in climate scenarios.

Nuissier, O., Joly, B., Joly, A., Ducrocq, V., & Arbogast, P. (2011). A statistical downscaling to identify the large‐scale circulation patterns associated with heavy precipitation events over southern France. Quarterly Journal of the Royal Meteorological Society, 137(660), 1812–1827. Portico. https://doi.org/10.1002/qj.866