基于集成生物圈模型的黄河流域植被演变及碳收支研究OACHSSCD

The Yellow River Basin served as a critical ecological barrier and economic corridor in China,characterized by complex topography,pronounced climatic variability,and intensive human-environment interactions,which resulted in significant spatial heterogeneity of ecosystem structure and function.In the context of implementing China's national strategy for ecological protection and high-quality development of the Yellow River Basin,a comprehensive understanding of vegetation dynamics and carbon cycling became essential for developing effective carbon offset mechanisms and enhancing regional ecosystem management capacity.Given the challenges in accurately simulating vegetation dynamics under the Yellow River Basin's complex terrain and diverse climatic conditions,this study developed an enhanced Integrated Biosphere Simulator(IBIS)adapted to the regional ecological characteristics.Based on the improved model,we systematically simulated vegetation evolution and carbon budget dynamics during 2000 to 2023,and examined their spatiotemporal patterns and relationships with hydroclimatic and topographic factors.Key findings included:(1)Model enhancements through sub-basin unit simulation,optimized leaf growth algorithms,and localized phenological parameterization significantly improved regional applicability,the improved IBIS model produced results closely aligned with multi-year observations from various flux stations and demonstrated strong consistency with remote sensing data(77％of computational units achieved R2＞0.8).(2)Temporally,Gross Primary Productivity(GPP),Net Primary Productivity(NPP),and Net Ecosystem Productivity(NEP)demonstrated mean annual increments of 6.4,4.7,and 4.3 g C m-2 a-1,respectively,indicating sustained vegetation improvement.Carbon dynamics exhibited pronounced monthly seasonality,functioning as a net sink during May—October and source during November—April,with peak net carbon sequestration(36 g C/m2)occurring in August.(3)Spatially,the basin operated as a net carbon sink with a mean annual uptake of 129.82 g C m-2 a-1 and total sequestration of 103.31 Mg C/a.Carbon budget exhibited a southeast-to-northwest decreasing gradient,with carbon source areas concentrated in arid northwestern regions,while mid-to-low elevation semi-humid and semi-arid zones demonstrated the most rapid carbon sink enhancement.(4)Precipitation emerged as a dominant control on carbon budget spatial patterns.Temperature demonstrated stronger enhancement of ecosystem respiration relative to precipitation,while NEP exhibited lower precipitation sensitivity compared to GPP and NPP.Overall,the improved IBIS model effectively captured the actual carbon budget characteristics of the Yellow River Basin ecosystem,providing robust scientific support for strategic regional ecological conservation and restoration efforts and for achieving China's dual carbon goals.