Water yield (WY) in the Upper Brahmaputra River (UBR) basin is important for sustaining the ecological environment in the headstream region and supplying valuable freshwater resources downstream. While recent studies indicated the presence of warming and greening trends in the region, the effects of these changes on WY are not yet understood. Here, on the basis of the Budyko framework and a random forest model, we assess the relative importance of climate and vegetation on WY changes in the UBR basin. We find that precipitation contributes to over 90% of the increase in annual WY, and is also the most important factor for WY during the wet season. During the dry season, however, vegetation, rather than precipitation, predicts the variability in WY. We suggest that vegetation may have changed the seasonality of water by storing water in the wet periods and releasing it in dry periods, which explains why WY increases significantly during the dry season. Our findings imply that vegetation greening in the UBR basin has the potential to increase drought resilience downstream, and protect food security from drought, highlighting the value of ecological restoration for water resource management.

布拉马普特拉河上游 (UBR) 流域的产水量 (WY) 对于维持源头地区的生态环境和供应下游宝贵的淡水资源具有重要意义。虽然最近的研究表明该地区存在变暖和绿化趋势，但尚不清楚这些变化对 WY 的影响。在这里，基于 Budyko 框架和随机森林模型，我们评估了气候和植被对 UBR 流域 WY 变化的相对重要性。我们发现降水对年 WY 的增长贡献了 90% 以上，也是雨季 WY 的最重要因素。然而，在旱季，植被而不是降水预测了 WY 的变化。我们认为植被可能通过在湿润期储存水并在干旱期释放它改变了水的季节性，这解释了为什么 WY 在旱季显着增加。我们的研究结果表明，UBR 流域的植被绿化有可能提高下游的抗旱能力，并保护粮食安全免受干旱影响，突出了生态恢复对水资源管理的价值。