地球信息科学学报 ›› 2012, Vol. 14 ›› Issue (1): 41-48.doi: 10.3724/SP.J.1047.2012.00041

• 陆地表层系统模拟 • 上一篇    下一篇

黑河山区流域平均坡长的计算与径流模拟

余文君1, 南卓铜2*, 李硕1, 李呈罡1   

  1. 1. 南京师范大学地理科学学院, 南京 210046;
    2. 中国科学院寒区旱区环境与工程研究所, 兰州 730000
  • 收稿日期:2011-04-20 修回日期:2011-11-04 出版日期:2012-02-25 发布日期:2012-02-24
  • 通讯作者: 南卓铜(1977-),男,浙江乐清人,博士,研究员。当前主要研究兴趣:寒区旱区水文建模、决策支持系统和地理信息系统。E-mail: nztong@lzb.ac.cn E-mail:nztong@lzb.ac.cn
  • 作者简介:余文君(1987-),女,湖北鄂州人,硕士研究生。主要从事SWAT模型的应用研究。E-mail: yuwenjun8899@163.com
  • 基金资助:

    国家科技部"863"课题(2008AA12Z205);国家自然科学基金重点项目(40730527);中科院重要方向项目(KZCX2-YW-Q10-1)。

Average Slope Length Calculation and Runoff Simulation

YU Wenjun1, NAN Zhuotong2*, LI Shuo1, LI Chenggang1   

  1. 1. School of Geography Science, Nanjing Normal University, Nanjing 210046, China;
    2. Cold and Arid Regions Environmental and Engineering Research Institute, CAS, Lanzhou 730000, China
  • Received:2011-04-20 Revised:2011-11-04 Online:2012-02-25 Published:2012-02-24

摘要: 流域平均坡长是侧向流和汇流时间计算的重要参数,其会影响地表径流的计算。应用SWAT 2005和ArcView GIS 3.2集成的AVSWAT模型,对黑河干流上游山区流域莺落峡出山口径流进行模拟,发现其计算的流域平均坡长存在较大误差,进而影响到模拟结果。利用子流域内已知的平均坡度和平均坡长建立回归方程,计算各子流域的平均坡长,替换AVSWAT计算的不合理值,在保持其他参数不变的情况下,模拟的月径流纳什系数从0.60提高到0.75,模拟结果得到显著提高。敏感性分析结果和径流曲线数(CN2)的分析也间接验证了流域平均坡长修正方法的可行性。在修正流域平均坡长后,对AVSWAT模型的其他参数CN2等进行优化,模拟的月径流的纳什系数达到0.81,表明本文建议的流域平均坡长计算方法是可以应用到实际的干旱区黑河流域并取得较好模拟效果。

关键词: 黑河流域, 平均坡长, SWAT, 敏感性分析

Abstract: Watershed average slope length (ASL) is defined as the average distance measured along the main channel from the watershed outlet to the basin divide. It is an important parameter in a hydrologic model. Theoretically ASL is related to the calculation of lateral flow and routing timing, which eventually impacts simulation of the total surface runoff. SWAT (Soil and Water Assessment Tools) is a river basin scale model developed to predict the effects of management decisions on water, sediment, nutrient and pesticide yields with reasonable accuracy on lager, and ungauged river basins. The AVSWAT model, an integration of SWAT2005 and ArcView GIS 3.2, was applied in this paper to simulate monthly stream flow (1990-2009) of the Yingluoxia outlet of the 10 000 km2 upstream basin of the Heihe River basin (HRB). The simulation showed that ASLs calculated by the AVSWAT model were not consistent with the actual cases in the upstream basin of HRB. As a result, it led to an inaccurate simulation. To address this problem, a new approach has been adopted to correct ASL of each sub-basin. A regression equation, which reflects the relationship between average slope and average length, was established by measuring average slope of each sub-basin. Using the corrected slope lengths and the default parameter set of SWAT together with meteorological and hydrologic data from 1990 to 2009, Nash-Sutcliffe coefficient (NSE) of monthly runoff simulation is obviously improved to 0.75 in contrast with 0.60 with uncorrected slope lengths and same parameter set. Sensitivity analysis and an examination of CN2 parameter were also conducted to prove the applicability of this correcting method. The results showed that corrected slope lengths were more suitable for the studied mountainous basin and also verified its applicability of the adopted correction approach. Using the corrected ASLs, an error-trial optimization was used to optimize other parameters. The validation with daily runoff from 2000-2009 showed an NSE of up to 0.81, which suggested an acceptable simulation for the study basin. We concluded on basis of corrected slope lengths quite good simulation can be achieved by parameter optimization. Therefore, the approach to correct ASL is feasible in mountainous basin, and the corrected slope lengths have made the stream flow simulation better.

Key words: Heihe River basin (HRB), average slope length, SWAT, sensitivity analysis