干旱区地理2026，Vol.49Issue(8)：1572-1586,15.DOI:10.12118/j.issn.1000-6060.2025.696
青海湖流域近25 a水碳变量时空变化与影响因素
Spatiotemporal changes and influencing factors of water and carbon variables in the Qinghai Lake Basin over the past 25 years
摘要
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 re-mote sensing and meteorological data from 2000 to 2024,and using net primary productivity(NPP),evapotrans-piration(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 effi-ciency.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 pre-cipitation.(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(precipi-tation,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 re-sources in the Qinghai-Xizang Plateau.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Key words
Qinghai Lake Basin/water-carbon coupling/net primary productivity/evapotranspiration/water use efficiency引用本文复制引用
闫鹏旭,张丽华,曾繁星,拜小辉,叶阳,曹轶杰..青海湖流域近25 a水碳变量时空变化与影响因素[J].干旱区地理,2026,49(8):1572-1586,15.基金项目
国家自然科学基金(41761043,41201196) （41761043,41201196）
甘肃省科技计划项目(20YF3FA042)资助 （20YF3FA042）
