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干旱区地理 ›› 2026, Vol. 49 ›› Issue (8): 1572-1586.doi: 10.12118/j.issn.1000-6060.2025.696 cstr: 32274.14.ALG2025696

• 气候与水文 • 上一篇    下一篇

青海湖流域近25 a水碳变量时空变化与影响因素

闫鹏旭1(), 张丽华1,2(), 曾繁星3, 拜小辉1, 叶阳1, 曹轶杰1   

  1. 1 西北师范大学地理与环境科学学院甘肃 兰州 730070
    2 甘肃省绿洲资源环境与可持续发展重点实验室甘肃 兰州 730070
    3 福州大学梅努斯工程学院福建 福州 350108
  • 收稿日期:2025-10-29 修回日期:2025-11-24 出版日期:2026-08-25 发布日期:2026-08-21
  • 通讯作者: 张丽华(1980-),女,博士,副教授,主要从事气候变化下的生态响应研究. E-mail: zhanglihualz@126.com
  • 作者简介:闫鹏旭(2004-),男,本科生,主要从事自然地理学研究. E-mail: ypengxuy@163.com
  • 基金资助:
    国家自然科学基金(41761043);国家自然科学基金(41201196);甘肃省科技计划项目(20YF3FA042)

Spatiotemporal changes and influencing factors of water and carbon variables in the Qinghai Lake Basin over the past 25 years

YAN Pengxu1(), ZHANG Lihua1,2(), ZENG Fanxing3, BAI Xiaohui1, YE Yang1, CAO Yijie1   

  1. 1 College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, Gansu, China
    2 Key Laboratory of Resource Environment and Sustainable Development of Oasis, Lanzhou 730070, Gansu, China
    3 Maynooth International Engineering College, Fuzhou University, Fuzhou 350108, Fujian, China
  • Received:2025-10-29 Revised:2025-11-24 Published:2026-08-25 Online:2026-08-21

摘要:

青海湖流域是青藏高原东北缘典型的高寒山地内流河流域,研究其水碳耦合机制对揭示高寒生态系统碳水交互规律、支撑水资源与碳汇协同管理具有重要意义。基于2000—2024年多源遥感与气象数据,以净初级生产力(NPP)、蒸散发(ET)和水分利用效率(WUE)为核心变量,系统分析其时空变化特征,并融合随机森林与XGBoost双机器学习方法,从空间与时间双维度解析驱动机制。结果表明:(1) 时间变化上,近25 a流域NPP与ET均呈显著上升趋势,增速分别为2.511 g C·m-2·a-1、4.470 mm·a-1,WUE以2017年为转折点呈先降后升的非线性变化。(2) 空间分布上,NPP与WUE呈“东南高、西北低”格局,ET呈“北高南低”分布,空间异质性显著。(3) 空间尺度上,海拔显著控制NPP与WUE的空间分异,对ET无显著影响;植被类型主导NPP与WUE空间差异,沼泽、栽培植被、草原及灌丛的固碳能力与水分利用效率更高;气温与叶面积指数(LAI)对NPP呈显著正向驱动,降水量与气温共同调控ET,WUE与降水量呈显著负相关。(4) 时间尺度上,LAI是NPP变化的核心驱动因子(RF特征重要性0.467,XGBoost为0.337),ET受LAI与降水协同调控,WUE对降水量、水体面积等水分条件更为敏感,模型解释难度显著高于单一水碳变量。研究结果揭示了高寒内流河流域水碳耦合的时空尺度驱动规律,可为青藏高原生态保护与水碳资源综合管理提供科学依据。

关键词: 青海湖流域, 水碳耦合, 净初级生产力, 蒸散发, 水分利用效率

Abstract:

The Qinghai-Xizang Plateau is an area sensitive to global climate change, and the Qinghai Lake Basin, along its northeastern edge, serves as a typical alpine inland river basin. Studying the water-carbon coupling mechanism is of great significance for revealing the laws of carbon-water interaction in alpine ecosystems and supporting the coordinated management of regional water resources and carbon sinks. Based on multi-source remote sensing and meteorological data from 2000 to 2024, and using net primary productivity (NPP), evapotranspiration (ET) and water use efficiency (WUE) as core variables, this study systematically analyzes their spatio-temporal change characteristics. It integrates random forest and XGBoost machine learning methods to analyze the driving mechanisms from two dimensions: Space (altitude, vegetation type, meteorological factors, leaf area index) and time (meteorological factors, leaf area index, water area). The results show that: (1) NPP and ET in the Qinghai Lake Basin have shown a significant upward trend over the past 25 years (growth rates of 2.511 g C·m-2 a-1 and 4.470 mm·a-1, respectively), WUE has shown a nonlinear change pattern, first declining and then rising, with 2017 as a turning point. (2) Spatially, NPP and WUE showed a pattern of “high in the southeast and low in the northwest”, whereas ET showed one of “high in the north and low in the south”, demonstrating significant spatial heterogeneity. (3) On a spatial scale, altitude significantly influences the spatial variabilities of NPP and WUE but has no significant effect on ET. Vegetation type dominates the spatial differences in NPP and WUE, with marshes, cultivated vegetation, grassland, and scrubland showing higher carbon sequestration capacity and water use efficiency. Among meteorological factors, temperature and leaf area index show a significant positive effect on NPP, whereas precipitation and temperature jointly regulate ET. WUE shows a significant negative correlation with precipitation. (4) On a temporal scale, LAI is a core driver of NPP changes (RF importance 0.467, XGBoost 0.337). ET was jointly regulated by leaf area index and precipitation. WUE is more sensitive to water conditions (precipitation, water area), and the model’s interpretability is significantly higher than that of single water and carbon variables. This study reveals the multi-scale driving laws of water-carbon coupling in alpine inland river basins, thus providing a scientific basis for ecological protection and comprehensive management of water-carbon resources in the Qinghai-Xizang Plateau.

Key words: Qinghai Lake Basin, water-carbon coupling, net primary productivity, evapotranspiration, water use efficiency