| TOPMODEL中地形指数ln 的新算法 |
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| 引用本文： | 雍 斌,张万昌,陈艳华.TOPMODEL中地形指数ln 的新算法[J].地理研究,2007,26(1):37-46. |
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| 作者姓名： | 雍 斌 张万昌 陈艳华 |
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| 作者单位： | [1]南京大学国际地球系统科学研究所,南京210093 [2]中科院大气物理所东亚区域气候-环境重点实验室,北京100029 |
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| 基金项目： | 国家重点基础研究发展规划项目（2006CB400502）;中科院“百人计划”启动项目（8-047401）;教育部科学技术重点项目（2001CB309404）致谢：本研究得到了南京大学国际地球系统科学研究所刘传胜博士在数据处理上的帮助. |
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| 摘 要： | TOPMODEL中地形指数ln (α/tanβ)被用来近似表征流域径流源面积和地下水水位的空间分布特征,目前广泛使用的计算地形指数的方法为多流向算法 (FD8算法)。本文首先介绍了多流向算法的基本原理,并基于此对流动累积分配中的有效等高线长度精确计算提出了几何锥面内切圆算法,同时改进了传统的地形指数中单位等高线汇流面积α的计算方法,增强了多流向算法对DEM中异常栅格的处理能力。改进后的地形指数新算法在两个不同流域和不同分辨率DEM上与传统多流向算法进行了对比分析。结果表明新算法在原理上更符合地形指数物理意义,实际应用中其计算结果更准确。这种地形指数新算法的提出对于流域水文过程机理分析及陆面过程定量化研究具有一定的现实意义。
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| 关 键 词： | 地形指数ln (α/tanβ) TOPMODEL 多流向算法 有效等高线 |
| 文章编号： | 1000-0585（2007）01-0037-10 |
| 收稿时间： | 2006-03-22 |
| 修稿时间： | 2006-03-222006-08-25 |
A new algorithm of the topographic index ln in TOPMODEL and its resultant analysis (1.International Institute for Earth System Science (ESSI),Nanjing University, Nanjing 210093,China|2.Regional Climate-Environment Research for Temperate East Asia, Institute of Atmospheric Physics, CAS, Beijing 100029,China) |
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| YONG Bin,ZHANG Wan-chang,CHEN Yan-hua.A new algorithm of the topographic index ln in TOPMODEL and its resultant analysis (1.International Institute for Earth System Science (ESSI),Nanjing University, Nanjing 210093,China|2.Regional Climate-Environment Research for Temperate East Asia, Institute of Atmospheric Physics, CAS, Beijing 100029,China)[J].Geographical Research,2007,26(1):37-46. |
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| Authors: | YONG Bin ZHANG Wan-chang CHEN Yan-hua |
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| Institution: | 1. International Institute for Earth System Science (ESSI |
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| Abstract: | Topographic index in TOPMODEL, ln (α/tanβ), is used to approximately characterize the spatial distributions of source area of surface runoff and groundwater tables in a catchment, the different algorithms utilized for computation of this parameter as well as the DEM in various spatial resolutions for such purpose can result in quite different estimations on spatial pattern and statistical distribution of the index. At present, the most widely utilized algorithm in the digital terrain analysis (DTA) method for calculating ln(α/tanβ) index is the multiple flow direction algorithm (FD8). On the basis of brief introduction to fundamental theory of FD8, a new algorithm to accurately calculate the effective contour length in the accumulated flow partitioning involved in ln(α/tanβ) computation by using internal tangent circle on conical surface method was proposed. Meanwhile the equations for calculating the cumulative upslope source area α were improved for rational computation of ln (α/tanβ) and a set of computing scheme for overcoming the noise of the abnormal grids to topographic index calculation was proposed. The new algorithm and original FD8 algorithm are both applied to two different catchments for comparison. Furthermore, we use four kinds of different resolutions (10-,20-,30- and 60-m) DEM to compute the spatial distribution of topographic index of Zhifanggou catchment. As a result, it is found that the new algorithm is more correct to express the relationship of upslope contribution area and soil water content in TOPMODEL and more accurate to reflect the hydrological similarity of real catchments. The new algorithm proposed in this paper will be useful to a certain extent to analyze watershed hydrological processes and quantify the land surface processes. |
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| Keywords: | TOPMODEL |
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