Mountain Basal Elevation Extraction in the Taiwan Island

Abstract

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 structure 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 hydrological 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 extracting 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 elevation and the quantitative research of mass elevation effect.