三江源区植被季节性变绿对生态环境和水资源安全有深远影响。本研究利用2003-2021年多源数据，采用趋势分析、相关分析和部分信息分解（PID）解耦分析，探讨了三江源地区植被季节性变绿的水分驱动因子及其对气候变化的响应关系。结果表明：（1）春、夏、秋季叶面积指数（LAI）的线性趋势总体上升，但是不同季节的环境条件差异显著。春、秋季降水量、土壤湿度（SM）和积雪覆盖（SC）的线性趋势也在增加，温度变化不明显；夏季温度的线性趋势略升高，降水量和SM略减少，SC变化不显著。（2）水分驱动因子对LAI的影响：相关分析显示，春、夏季LAI与SM显著正相关，秋季不显著；LAI与SC的相关性各季节均较弱。引入PID解耦分析方法，有效地揭示了SM和SC对LAI的非线性和协同影响。SC在春、秋季影响LAI变化的独立信息贡献更高，成为主要水分驱动因子，夏季则SM贡献更大；同时，SM和SC的协同作用在各季节对LAI变化起重要作用，协同信息贡献均超过30%。（3）水分驱动因子对气候变化的响应：相关分析显示，SM在各季节均与降水显著正相关，春季与温度显著负相关；SC在各季节均与降水显著正相关，春、秋季与温度显著负相关。PID分析也表明，降水是影响三个季节SM和SC变化的主要气象因子，对SM和SC的独立贡献均高于温度，但温度和降水对各季节的SM和SC的协同作用也不容忽视。

The seasonal vegetation greening in the Three River Source Region（TRSR）has a profound impact on the ecological environment and water resource security. In this study，the moisture drivers of seasonal vegetation greening in the TRSR and their responses to climate change were investigated using multi-source data from 2003 to 2021，through the application of trend analysis，correlation analysis and partial information decomposition （PID）analysis. The results showed that（1）the linear trend of the Leaf Area Index（LAI）generally increased in spring，summer and autumn，although the environmental conditions varied significantly between seasons. Linear trends in precipitation，soil moisture（SM）and snow cover（SC）also increased in spring and autumn，with in‐ significant changes in temperature. In summer，linear trends of temperature were slightly higher，with slight de‐ creases in precipitation and SM，as well as insignificant changes in SC.（2）Effects of moisture drivers on LAI： correlation analyses indicated that LAI was significantly positively correlated with SM in spring and summer， but not in autumn. The correlation between LAI and SC was weak in all seasons. By introducing the PID analysis method，the nonlinear and synergistic effects of SM and SC on LAI were effectively revealed. The independent information contribution of SC to LAI changes was higher in spring and autumn，making it the main moisture driver in these seasons，while SM contributed more in summer. At the same time，the synergistic effects of SM and SC played an important role in the changes of LAI in all seasons，with the synergistic information contribution exceeding 30% in all seasons.（3）Response of moisture drivers to climate change：correlation analyses showed that SM was significantly positively correlated with precipitation in all seasons and significantly negatively correlated with temperature in spring；SC was significantly positively correlated with precipitation in all sea‐ sons and significantly negatively correlated with temperature in both spring and autumn. PID analyses also indicated that precipitation was the main meteorological factor influencing changes in SM and SC across the three seasons，with a higher independent contribution than temperature. However，the synergistic effects of temperature and precipitation on SM and SC in all seasons should not be overlooked.