Thermodynamic-microphysical coupling mechanisms of hydrometeor phase transitions during persistent wind turbine icing

) and subsequently became supercooled in the underlying cold layer, accelerating blade icing. Finally, the mixed-phase stage was driven by a melting-refreezing mechanism. Mid-level dry-cold air intrusion weakened the warm layer, causing descending solid hydrometeors to undergo only partial melting. These hydrometeors then formed mixed-phase precipitation (coexisting ice pellets and trace supercooled rain) within the deep cold layer, maintaining the farm-wide shutdown.