Vegetation Change along the Qinghai-Xizang Highway and Railway from 1981 to 2001
In this article, spatial distribution and dynamic change of vegetation cover along Qinghai-Tibet highway and railway were studied using NOAA AVHRR-NDVI monthly data from 1981 to 2001. By analyzing the data, we found that the NDVI value in July, August and September are rather higher among a year, and obtained a linear trend by calculating NDVI of each pixel which was computed through average value of NDVI in July, August and September. The map showed the spatial and relative changes of NDVI in each pixel by means of GIS. The results are as follows: 1) Vegetation cover of the research area by NDVI tends to be high at the two ends of the area and low in the middle, and agriculture area > alpine meadow > alpine grassland > desert grassland; 2) In the research area, the area of high increase, slight increase, no change, slight decrease and high decrease are 0.29%、14.86% 、67.61% 、16.7% and 0.57% of the whole region. The increase and high decrease of vegetation cover pixels distribute in the agriculture and alpine meadow, light decrease pixels distribute in the alpine grassland and desert grassland;3)In the area where human being live, the trend of change is obvious, such as the valleys of Lasha river and Huangshui river and area along the Yellow river; on the high altitude area with fewer people living in, the trend of change is relatively low, like the area of Kekexili; 4) Human being' s behaviors is a key factor followed by the climate changes affecting vegetation coverage.
NETL
NSTL
万方数据
维普
