Snowmelt is a critical water supply that affects the environmental security and sustainable development. However, the dynamic contributions of climatic factors to snowmelt and their impacts on soil moisture (SM) and vegetation growth remain unclear. In this study, by combining changes in spring snowmelt (snow water equivalent), climatic factors (precipitation and temperature), SM, and vegetation growth (normalized difference vegetation index [NDVI]) during 1982–2018, the spatiotemporal patterns in snowmelt and its mutual effects on SM and NDVI in a mid-high latitude watershed (Mongolia) were investigated. The results showed that spring snowmelt has decreased (-0.54 m/yr, p < 0.05) in Mongolia, with cold season temperature and precipitation identified as key influencing factors. The negative association between cold season temperature and snowmelt is intensifying (-0.0010 mm/yr, p > 0.05), while the positive influence of cold season precipitation is weakening (-0.0004 mm/yr, p > 0.05). Additionally, snowmelt provides 30 % of SM, and rising spring temperatures, along with reduced snowmelt, is the main reasons for SM decline (0.001 m³/m³/yr, p < 0.05). The negative impact of spring temperature on SM is growing (-0.0029 %/yr, p < 0.05), while snowmelt's positive contribution is diminishing (-0.0011 %/yr, p < 0.05). Furthermore, spring temperature has the strongest direct effect (positive) on vegetation, while SM exerts the greatest total influence (positive). Snowmelt indirectly affects (positive) vegetation through its role in SM. Despite vegetation increased in 60.5 % of the area, the declining trends in SM and snowmelt, alongside the reduced contribution of SM to vegetation (-0.0028/yr, p < 0.05), suggest an increased risk of future drought. Overall, this study provides new insights into the dynamics and interrelationships between snowmelt, SM, and vegetation in mid-to-high latitude regions, offering valuable implications for sustainable development decision-making.

中文翻译：

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重访四十年来中高纬度流域融雪动力学及其对土壤水分和植被的影响


融雪是影响环境安全和可持续发展的关键水源。然而，气候因素对融雪的动态贡献及其对土壤水分 （SM） 和植被生长的影响仍不清楚。本研究结合 1982—2018 年春季融雪（雪水当量）、气候因子（降水和温度）、SM 和植被生长（归一化植被指数 [NDVI]）的变化，研究了中高纬度流域（蒙古）融雪的时空格局及其对 SM 和 NDVI 的相互影响。结果表明，蒙古国春季融雪量减少 （-0.54 m/yr， p < 0.05），寒冷季节温度和降水是主要影响因素。寒冷季节温度与融雪之间的负相关正在加强（-0.0010 mm/yr，p > 0.05），而寒冷季节降水的积极影响正在减弱（-0.0004 mm/yr，p > 0.05）。此外，融雪提供了 30% 的 SM，春季气温升高和融雪减少是 SM 下降的主要原因 （0.001 m³/m³/yr， p < 0.05）。春季温度对SM的负面影响越来越大（-0.0029 %/yr，p < 0.05），而融雪的积极贡献正在减少（-0.0011 %/yr，p < 0.05）。此外，春季温度对植被的直接影响最强（正），而 SM 对植被的总体影响最大（正）。融雪通过其在 SM 中的作用间接影响（正）植被。尽管该地区 60.5% 的植被增加了，但 SM 和融雪的下降趋势，以及 SM 对植被的贡献减少（-0.0028/年，p < 0.05），表明未来干旱的风险增加。 总体而言，本研究为中高纬度地区融雪、SM 和植被之间的动态和相互关系提供了新的见解，为可持续发展决策提供了有价值的启示。