Large-scale drivers of the mistral wind: link to Rossby wave life cycles and seasonal variability

Abstract. The mistral is a northerly low-level jet blowing through the Rhône valley in southern France and down to Gulf of Lion. It co-located with cold sector lee cyclone Genoa, behind an upper-level trough north Alps. wind has long been associated extreme weather events Mediterranean, while extensive research focused on lower-tropospheric cyclogenesis, different upper-tropospheric large- synoptic-scale settings involved producing are not generally known. Here, isentropic potential vorticity (PV) structures governing occurrence classified using self-organizing map (SOM) clustering algorithm. Based upon 36-year (1981–2016) database daily ERA-Interim PV data, 16 distinct mistral-associated emerge. Each flow pattern corresponds type or stage Rossby wave life cycle, from broad troughs thin streamers distinguished cutoffs. these patterns exhibits surface impact terms cyclone, turbulent heat fluxes, wind, temperature precipitation. A clear seasonal separation between clusters evident, transitions correspond Rossby-wave-breaking processes. This analysis provides new perspective variability Genoa cyclogenesis general, linking their over Europe, Mediterranean Africa.