各类型草地生长过程及自然因子特征遥感研究-以甘肃省为例

以具有丰富草地类型的甘肃省为研究区,研究了中国6种主要类型草地各自植被生长过程特征并量化分析了影响各类型草地分布的自然因子特征.其中,6种草地类型是基于TM和MODlS两种遥感数据,综合运用自动分类及决策树分类方法划分而得,按照分布面积从大到小依次为典型草地、草甸草地、荒漠草地、高寒草甸、高寒草原、灌丛草地.引入了区域平均EVI值作为遥感因子,构建6种类型草地生长过程曲线,揭示各类型草地生长过程及相对生物量之间的差别,给出遥感划分草地类型的最佳时相.运用空间叠加分析手段,揭示了各种类型草地分布区的自然因子特征.分析发现水热的配比及海拔是影响草地类型的主导因子,坡度的影响相对较弱.

Study on Growth Period of Each Type of Grassland and Their Natural Conditions Based on Remote Sensing in Gansu Province

Grassland types is abundance in the up stream of Yellow river.Take Gansu province as a sample area, growth period profile of each grassland types are constructed and their distribution area''s natural conditions are analyzed.Utilizing the advantages of high temporal resolution of MODIS and high spatial resolution of TM, grassland types are classified to 6 types, including meadow steppe, typical steppe, desert steppe, high-cold meadow steppe, high-cold typical steppe and shrub herbosa.Induce average region based EVI and construct growth period profile, which show, clearly, the differences among 6 grassland types.Thus point out the optimal data to divide 6 grassland types.By overlying cumulative annual precipitation, cumulative annual temperature, elevation and slope on the grassland t ypes, spatial analysis shows t hat p ropo rtio n of p recipitatio n and temperat ure, terrain are t he t wo chief facto r affecting grassland t ypes, slope is a weak nat ural effecting facto r.