3.1.1 Mamukao River
In the Mamukao River Basin, there are differences in snowmelt processes between spring and winter. During spring (see Fig 3(a)), the rate of snowpack ablation was slower. Snowfall increased the proportion of snow cover in the watershed to 96.56%, and within 7 days after snowfall, the snowpack changed more slowly, with the area decreasing by only 2.96%. However, the rate of snow ablation accelerated during days 8-11, and the area decreased by 3.24%. It started to level off at day 12, and then the next snowfall occurred at day 14, causing the snowpack area to rebound. This snow ablation process had an ablation rate of -0.707%/day. During winter snowfall (see Fig. 3(b)), the snowfall increased the proportion of snow area in the watershed to 99.18%, and the proportion of snow cover on day 2 was 96.73%, which was less variable. From day 3 onwards, the proportion of snow cover declined sharply, and the snow-covered fraction (SCF) decreased by 75.16% in the period of days 2-10, after which the trend of change became stable. The rate of decline was -5.216%/day in 17 days, which was much larger than the spring snow ablation rate. Therefore, the spring snow ablation rate is less than the winter snow accumulation in the Mamukao River basin.