3.3.2 Impact factor analysis
In Figure 10, the cumulative contribution of the top 10 environmental factors in different seasons or regions is examined in relation to stable snowpack. The results show that these top 10 factors account for more than 85% of the overall contribution, suggesting their significant influence on the distribution pattern of stable snowpack. Consequently, this study focuses solely on analyzing the top 10 environmental factors based on the magnitude of their contribution rate. In the Mamukao River Basin (Fig 10(a,b)), there are variations in the dominant factors that stabilize snowpack patterns during spring and winter. The three most significant contributing factors in spring were Altitude (49.38%), Snow Water Equivalent (Suwd) (21.72%), and Incoming Shortwave Radiation (Asrad) (7.87%). Among these factors, Suwd (37.75%) and Altitude (36.56%) had the highest replacement importance, indicating their greater influence compared to other factors. The combined analysis of contribution rates and replacement importance suggests that the distribution pattern of stable snowpack in the Mamukao River during spring is primarily influenced by Altitude, Suwd, and Asrad. In winter, the top three contributing factors were Altitude (42.66%), Accumulated Snow Depth (Awd) (17.2%), and Frozen Precipitation (Fpr) (7.81%). Altitude (46.12%) and Fpr (33.45%) had the highest replacement importance, indicating their significant influence on the distribution pattern of stable snowpack in the Mamukao River during winter. Therefore, the three main factors influencing the distribution pattern of stable snowpack in winter in the Mamukao River are Altitude, Fpr, and Awd.
In the Hanliu River basin (Fig 10(c,d)), the distribution pattern of stable snowpack is influenced by different factors in spring and winter. In spring, the three most significant contributing factors are Foa (53.04%), Cra (27.58%), and Alt (13.63%), with Foa being the most influential. The two factors with the highest replacement importance are Alt (64.43%) and Foa (25.62%). Therefore, the dominant factors in stabilizing the snowpack in the Hanliu River during spring are Foa, Cra, and Alt. In winter, the three factors with the highest contributions are Foa (29.58%), Wpr (20%), and Cra (14.14%), while the two factors with the highest replacement importance are Alt (41.87%) and Und (26.43%). Taking into account both the contribution rate and replacement importance, the factors that have a greater influence on the spatial distribution pattern of stable snowpack in winter are Foa, Wpr, Cra, Alt, and Und.