基于RS和GIS的藏北地区草地退化动态监测与驱动力分析——以申扎县为例

Research on the Dynamic Change of the Grassland Degradation in Shenzha County with RS and GIS Technology

该文运用遥感(RS)和地理信息系统(GIS)技术,以1990年、2000年和2009年陆地卫星遥感影像为信息源,通过提取植被指数和遥感二分像元模型,估算了西藏申扎县不同时期的植被覆盖度.结果表明:在整个研究时段内,草地退化的面积在增加,从1990年到2009年,草地植被覆盖面积减少了92.88万hm2,占申扎县草地面积的33.24%.从动态变化来看,1990年到2000年,草地退化较严重;2000年到2009年,草地退化趋势得到控制,并有一定程度恢复.该文还分析了过去20年来藏北高寒草地生态系统退化的时空格局与过程及驱动因素,提出了预防草地退化的法律政策和技术措施,为退化高寒草地的恢复、治理和区域可持续发展提供了科学依据.

In this paper,on the basis of RS technique and GIS technique,remote sensing images acquired from Landsat of three periods（1990,2000 and 2009） as information source were used to estimate the vegetation coverage of study area in different periods by extracting NDVI and improved dimidiate pixel estimating model.And the results show that the area of grassland degradation is on the increase in the whole studied periods,and 928800 hm2 grassland lost in the past 20 years,taking up 33.24% of the total grassland area in Shenzha county.There is more serious grassland generation phenomenon from 1990 to 2000 and the increasing trends of grassland degradation were not very obvious during 2000-2009 on the angle of dynamic change.At the same time,this paper analysed the space-time structure,process and driving factors of northern Tibetan alpine grassland ecosystem degradation in the past 20 years,and put forward to the laws,policies and technical measures for degradation alpine meadow to prevent the grassland degradation in order to provide scientific basis for restoration,governance and the regional sustainable development of study area.