基于WaSSI模型的珠江流域水-碳耦合模拟

Simulation of water and carbon coupling of the Pearl River basin based on the WaSSI model

流域水循环和碳循环通过植物光合作用与蒸散发(ET)过程紧密相联,两者在流域尺度上的耦合模拟研究是实现水、碳资源综合管理的重要基础。本研究通过对WaSSI(供水压力指数)生态水文模型进行适当改进,建立并验证了珠江流域水-碳耦合模拟模型(WaSSI-PRB),将珠江流域划分为1715个子流域,选定1980—2004年为率定期、2005—2016年为验证期,并对径流、蒸散发和总初级生产力(GPP)等3个关键水-碳通量的模拟结果进行验证。结果表明:西江、北江、东江的水文控制站,径流模拟纳什效率系数(NSE)和决定系数(R^(2))在率定期均达0.80以上,在验证期均达0.75以上;相较于MODIS、PML、SSEBop、VPM等大尺度遥感数据产品,WaSSI-PRB模型能更好地模拟ET和GPP的时空分布特征。总体而言,WaSSI-PRB模型在珠江流域具有较好的适用性,可作为量化分析流域水-碳平衡及其对变化环境响应关系的一种有效工具。

Watershed water and carbon cycles are closely linked through plant photosynthesis and evapotranspiration(ET).Simulation of coupled water-carbon cycles at the watershed scale is important for the comprehensive management of water and carbon resources.By improving the WaSSI(water supply stress index)eco-hydrological model,we established and verified a water-carbon coupling simulation model for the Pearl River Basin in south China(WaSSI-PRB).The Pearl River Basin was divided into 1715 watersheds.The simulations of three water-carbon flux parameters,such as runoff,ET and gross primary productivity(GPP),were verified with 1980-2004 as the calibration period and 2005-2016 as the validation period.The Nash-Sutcliffe efficiency coefficient(NSE)and the coefficient of determination(R~2)of the simulated runoff at the controlling hydrological stations of Xijiang,Beijiang and Dongjiang were greater than 0.80 during calibration period and greater than 0.75 during validation period.Compared with MODIS,PML,SSEBop,VPM and other large-scale remote sensing data products,WASSI-PRB showed a better performance in capturing the spatiotemporal variations of ET and GPP.In general,WaSSI-PRB model had good applicability in the study area,and could be used as an effective tool to quantitatively analyze water-carbon balance and their responses to environmental changes in the Pearl River Basin.