摘要
在流域水文学研究与应用领域中 ,坡面水流占有十分重要的地位 ,但如何获取坡面水流的有效糙率是至关重要的一步。本文针对林地地表径流运动的形成过程和运动特点 ,建立了林地渗透坡面地表径流运动基本方程 ,通过讨论土壤水分运动和地表径流运动参数 ,将土壤水分运动简化为一维Smith Parlange模型 ,地表径流简化为运动波模型 ,采用一步Lax Wendroff有限差分格式进行数值模拟 ,以最小离差平方和为目标函数 ,通过叠代计算获取林地地表径流的有效糙率。根据人工模拟降雨地表径流过程实测资料计算了油松林、刺槐林、蒙古栎林 3种林分的有效糙率 ,计算结果表明 ,2 2a生刺槐林地的最大 ,在 0 1 93 1～ 0 2 1 3 1之间 ;其次为 3 0a生蒙古栎林地 ,为 0 1 70 1 ;2 0a生油松林地为 0 1 42 3。从参数寻优的结果来看 ,m值在2 76～ 3 0 90之间 ,接近层流时的m =3。为检验模型和参数的可靠性 ,用计算获得的林地坡面径流过程线与实测径流过程线进行了比较 ,结果表明采用此模型和数值模拟方法可以很好地模拟渗透坡面林地地表径流运动。
Research into and apply of the overland flow model have been one of the major themes in hydrology due to the basic unit on which physically based distributed parameter hydrological model development is based. Runoff coefficient calculation of the overland, however, is the critical step in doing so. On the other hand, it is necessary to determine the coefficient for evaluating the forest plantation impacts on the surface runoff. Dynamical overland flow model under artificial rainfall simulations was developed for forested infiltrating slope based on the surface runoff generation and hydrological traits. Soil water movement was simplified as one dimensional vertical flow while overland flow kinematic wave model. Single step Lax Wendroff difference scheme and iterative calculation method were adopted to simulate the overland flow and estimate the surface coefficient. Parameter optimisation results have shown that the overland flow resistance(effective surface roughness)of Black locust( Robinia pseudoacacia L.)plantation plots are between 0 1931～0 2131, Mongolian oak( Quercus monogolica) plot 0 1701, and Chinese pine( Pinus tabulaeformis Carr.)plantation 0 1423. Optimised m values in the overland flow kinematic approximation q=αh m are between 2 76～3 090 with are near m=3 representing sheet flow. The model and parameter verification results have shown that computed and measured rising limb and partial equilibrium hydrographs fitted very well.
出处
《林业科学》
CAS
CSCD
北大核心
2000年第5期22-27,共6页
Scientia Silvae Sinicae
基金
国家"九五"攻关课题资助 !编号 :96 0 0 7 0 1 0 2
关键词
渗透坡面
坡面流
数值模拟
有效糙率
林地
Infiltrating slope, Overland flow, Numerical simulation, Effective surface roughness, Parameter optimisation
