The Research On Ecological Hydrology Variation Along The Qinghai-tibet Railway

The section of Qinghai-Tibet railway from Golmud to Lhasa,with total length of1142 km,passes through typical alpine meadow area,alpine grassland area and permafrost region where in permafrost region occupies 546 km.Both during construction and since opened to traffic,the impacts of Qinghai-Tibet railway on ecological environment along and its recovery has become the focus of society and scholars at present.Therefore,the study on the eco-hydrological changes along Qinghai-Tibet railway is of significant scientific value.Taking advantage of IDL programming language at ArcGIS and ENVI software platform,this thesis analyzes the temporal and spatial changes of vegetative coverage along Qinghai-Tibet railway from 2000 to 2014 through MODIS NDVI data.On basis of filter analysis function of Matlab,it uses vertical railway sectional NDVI data to determine the influence sphere of vegetation along Qinghai-Tibet railway by method of median filter.Also using the data of temperature and rainfall form surface weather station,this thesis analyzes the main factors that affect the growth of vegetation along on basis on multiple linear regression model.Moreover it analyzes the influence of climate factors and human activity on vegetation respectively with the method of residual analysis and separates the influence of climate factors and human activity from each other.According to research results,in the 15 years the NDVI along Qinghai-Tibet railway has been little changes except that near Tang-ku-la Mountains since the railway was open to traffic.Specifically,the NDVI of section from Amdo to Lhasa has risen slightly;the max influence sphere of vegetation along Qinghai-Tibet railway is 10 km and for the rest most part the influence sphere is around 5km.In general,the greater the NDVI value the area has,the smaller the influence sphere is;on the contrary,the influence sphere is larger.The influence of rainfall and temperature on vegetation is the most significant at Damxung region;while influence of rainfall on vegetation is the least significant at Wudaoliang region and influence of temperatureon vegetation is the least significant at Tuotuohe area.Human activity make the vegetation on north Tang-ku-la area worse;while it make vegetation on south Tang-ku-la prefecture better.This study provides some reference for understanding the influence on ecological vegetation along the railway projects and ecological protection.