摘要
水土流失对流域生态危害严重,输沙量模拟和预测可以为流域水土流失防治提供依据,因此精确的输沙模型是流域水土流失治理的重要工具。为了精确模拟变化环境下黄土高原年输沙量,该研究基于黄土高原19个水文站的径流和输沙数据,通过随机森林变量重要性度量方法评估年径流侵蚀功率、淤地坝指数、淤地坝相对指数、归一化植被指数、不透水地面积等因子对流域年输沙量的影响,使用非线性最小二乘法估算年输沙模型参数,对比分析不同因子组合的年输沙模型精度,提出适用性较强的黄土高原年输沙模型,据此开展年输沙量变化贡献率分析。结果表明:1)以幂函数形式构建的仅含径流侵蚀功率单因子输沙模型精度与流域面积有显著的负相关关系,相关系数为-0.505(P<0.05),模型精度随着流域面积增大而下降,在面积大于7000 km^(2)的流域适用性较差;2)年径流侵蚀功率、淤地坝指数及不透水地面积因子组合建立的多因子年输沙模型在黄土高原适用性最佳,模型在率定期纳什效率系数平均值为0.84,均方根误差平均值为0.21亿t,在验证期纳什系数平均值为0.79,均方根误差平均值为0.27亿t。3)影响研究流域年输沙量变化的因素依次是:年径流侵蚀功率、不透水地面积和淤地坝指数。研究可以为黄土高原不同区域水土流失防治和生态治理工作提供理论支撑。
Soil and water loss has been one of the most serious hazards to the basin ecology in recent years.An accurate sediment transport model can greatly contribute to the control of soil and water loss in the basin.This study aims to explore the variation trend of sediment transport by Mann-Kendall.The runoff and sediment transport data was also collected from the 19 hydrological stations in the Loess Plateau.Annual sediment transport model was then established to take the runoff erosion power as the core factor in Pearson correlation analysis.Random forest variables were selected to evaluate the influence of factors(such as annual runoff erosion power,check-dam index,check-dam relative index,normalized difference vegetation index(NDVI)and impervious land area)on the annual sediment transport of the basin.The parameters were also determined in the annual sediment transport model by nonlinear least square method.The accuracy of the model was compared with different factor combinations.The annual sediment transport model was proposed with the strong applicability for the Loess Plateau.The attribution analysis was finally carried out on annual sediment transport.The results showed as follows:1)It was reasonable to choose the runoff erosion power as the core factor in the annual sediment transport model.But there was a significant negative correlation between the area of watershed and the accuracy of the single factor annual sediment transport model with only annual runoff erosion power that built by the power function.The correlation coefficient was-0.505(P<0.05).The accuracy of the single factor model decreased with the increase of the watershed area.As such,the applicability of the model was poor in watersheds larger than 7000 km^(2).2)The best performance was achieved in the multi-factor annual sediment transport model with the combination of annual runoff erosion power,check-dam index and impervious area factors.The average NSE and RMSE values of the model were 0.84 and 0.21108t at the calibration rate,0.79 and 0.2710
作者
于坤霞
李天毅
贾路
李占斌
李鹏
丛佩娟
李斌斌
YU Kunxia;LI Tianyi;JIA Lu;LI Zhanbin;LI Peng;CONG Peijuan;LI Binbin(State Key Laboratory of Eco-Hydraulics in Northwest Arid Region,Xi’an University of Technology,Xi’an 710048,China;Key Laboratory of National Forestry and Grassland Administration on Ecological Hydrology and Disaster Prevention in Arid Regions,Xi’an University of Technology,Xi’an 710048,China;Monitoring Center of Soil and Water Conservation,Ministry of Water Resources,Beijing 100053,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2024年第10期107-116,共10页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金项目(U2040208、52079104)
陕西省重点研发计划项目(2023-ZDLSF-60)。
关键词
侵蚀
沙
径流
年输沙量
径流侵蚀功率
淤地坝指数
不透水地面积
贡献率
erosion
sediment
runoff
annual sediment transport
runoff erosion power
check-dam index
impervious area
contribution rate
