Extreme minimum temperature and precipitation indices drive the shortening of snow cover duration in China

Study region This research focuses on China's stable snow cover regions, encompassing the Mid-Temperate Arid, Semi-Arid, and Semi-Humid Zones, alongside the Plateau Temperate Semi-Arid Zone. Spanning 1980–2019, this domain constitutes a critical component of global hydrological and energy cycles, demonstrating pronounced susceptibility to recent warming trends. Study focus To address the insufficient quantification of snow characteristic (SC) responses to extreme climate, we analyzed snow onset date (SOD), snow end date (SED), and snow cover duration (SCD). Using an integrated framework of trend analysis, Random Forest, and Structural Equation Modeling (PLS-SEM), we disentangled the interplay between SC and extreme indices while accounting for mean warming. New hydrological insights for the region The analysis reveals pervasive snow contraction, with SCD shortening by −2.56 days/5a. The annual minimum daily minimum temperature (TNn) and continuous dry days (CDD) emerge as primary drivers. Other factors regulate snow by modulating these extremes: Leaf Area Index for low vegetation (LAI-LV) influences TNn to delay snow phenology, while nitrous oxide (N 2 O) affects CDD to advance SED and truncate the snow season. These findings decode complex driver-climate interactions, supporting refined snow modeling under climate warming.