Understanding the interactions between vegetation coverage and precipitation is critical for the restoration and conservation of fragile ecosystems, particularly in regions with unique climatic conditions such as the dry-hot valley of the Jinsha River. Using MOD13Q1 vegetation data and IMERG satellite precipitation data from 2001 to 2020, this study investigated the trends, time-lag, and accumulation effects between vegetation coverage and precipitation across multiple spatial and temporal scales. Additionally, the vertical migration characteristics of these effects were analyzed. Our findings showed that: (1) Vegetation coverage in the valley is generally low, particularly in the inner canyons and during the dry winter-spring seasons. (2) Vegetation responses to precipitation were dominated by accumulation effects (79.91 %) and combined lag-accumulation effects (13.14 %), with average lag and accumulation periods of 1.17 and 2.05 months, respectively. (3) Woodland and savanna shrub vegetation exhibited longer, more complex responses, whereas grassland and savanna showed quicker and more direct responses to precipitation. (4) Lag and accumulation periods increased with altitude, while time effect area anomalously decreased from 1200 to 1600 m elevation zone toward ridges and riverbeds. Below 1200 m, combined and accumulation effects weakened, whereas above 1200 m, accumulation effects intensified, intuitively characterizing the extension of the more significant dry-hot effect to higher altitudes above 1200 m, which is unprecedented in previous studies. These results provide critical insights for ecological restoration strategies and sustainable water resource management in the Jinsha River dry-hot valley.

中文翻译：

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金沙江干热河谷植被对降水的时滞与积累响应在多个时空尺度上

了解植被覆盖率和降水之间的相互作用对于恢复和保护脆弱的生态系统至关重要，尤其是在具有独特气候条件的地区，例如金沙江干热河谷。本研究利用 2001 年至 2020 年的 MOD13Q1 植被数据和 IMERG 卫星降水数据，研究了多个空间和时间尺度上植被覆盖和降水之间的趋势、时间滞后和积累效应。此外，还分析了这些效应的垂直迁移特征。研究结果表明：（1） 河谷植被覆盖率普遍较低，尤其是在峡谷内层和干燥的冬春季节。（2） 植被对降水的响应以积累效应 （79.91 %） 和滞后-积累效应 （13.14 %） 为主，平均滞后期和 2.05 个月分别为 1.17 个月和 2.05 个月。（3） 林地和热带稀树草原灌木植被表现出更长、更复杂的响应，而草原和热带稀树草原对降水表现出更快、更直接的响应。（4） 滞后和积累期随海拔增加而增加，而时间效应区从 1200 m 海拔区向山脊和河床异常减少。在 1200 m 以下，综合效应和积累效应减弱，而在 1200 m 以上，积累效应加强，直观地描述了更显着的干热效应扩展到 1200 m 以上的更高海拔，这在以前的研究中是前所未有的。这些结果为金沙江干热河谷的生态恢复策略和可持续水资源管理提供了重要见解。