山体基面高度的提取方法——以台湾岛为例

Mountain Basal Elevation Extraction in the Taiwan Island

山体基面高度的差异影响山体自身对其水热条件的再分配,进而影响山地垂直带谱的结构和分布,是决定垂直带分布高度的重要因子之一。目前,山体基面高度还没有一个准确科学的定义,也缺乏一个有效的数字化、定量化提取方法。本文以台湾岛为例,使用30m分辨率的ASTER GDEM数据,提出了一种提取山体基面高度的方法。首先,以地形特征与水文特征提取方法获得主山脊线与主山谷线,然后,以地形地貌单元自动提取方法获得山体轮廓界线,再依据提取出的主山脊线、山体轮廓界线及主山谷线,划分山体基面高度分区,依据山体基面分布特征确定各分区的基面高度值,将台湾山地划分出6个不同的山体基面高度(0m、150m、200m、600m、630m和650m)。该方法为大范围山体基面高度的快速、准确提取,以及山体效应定量化研究提供了重要的技术支撑。

Mountain basal elevation （MBE） is the elevation of the base which mountains uplift from. The variation of MBE affects the redistribution of water and heat conditions in mountain areas, and the struc- ture and distribution of mountain altitudinal belts. But so far, there has been no accurate and scientific concept of MBE and no effective method to quantitatively extract it. This paper discusses the features of MBE, and develops a new quantitative method for MBE extraction based on topographical features. There are several algorithms available for automated extraction of topographical features, including ridge line, valley line and the boundary of mountains, and most of the current approaches are mainly based on regular statistic unit. This paper takes Taiwan mountain areas for experimental zone, and uses ASTER GDEM at resolution of 30m. Firstly, extracting main ridge line and main valley line by terrain analysis and hydro- logical analysis, and using topographical features to extract the boundary of mountains. Then based on the result of extraction, the distribution and the value of MBE are determined. The results show that the mountain areas of Taiwan can be divided into six MBE areas （0m, 150m, 200m, 600m, 630m, and 650m）. The results can represent the distribution of Taiwan mountain basal elevation. This MBE extrac- ting method is based on sophisticated algorithms, so it can improve the efficiency of the extraction process and the accuracy of results. The method could promote the extraction of the world＇s mountain basal eleva- tion and the quantitative research of mass elevation effect.