基于TM-NDVI的草地生产力遥感监测研究

Research on the Remote Sensing Monitoring of Grass Productivity Based on TM-NDVI

采用地面调查与"3S"技术相结合的方法,以三江源玛多县为例,在计算玛多县TM影像归一化植物指数(NDVI)分布图的基础上,建立监测样点地上生物量与NDVI的遥感模型,结合青海省草地生产力划分等级,得出玛多县草地生产力等级分布图,实现草地生产力监测由点到面扩展。研究表明:①2009年玛多县草地覆盖面积约222万hm2,NDVI以0～0.5为主,占玛多县草地总面积的88.64%;②监测样点生物量与NDVI相关系数达0.7以上,呈显著相关关系,模型可定量表达为生物量=552.632×NDVI1.137;③玛多县草地生产力等级以750～3 000 kg/hm2为主,占玛多县总草地面积72%;草地生产力最高等级为4 500～6 000 kg/hm2,但占玛多县总草地面积不到1%。

Combined the methods of ground surveys and ＂3S＂ technology,with Maduo County as the example,the remote sensing model between monitor sampling point ground biomass and NDVI was established based on the NDVI distribution of Maduo County TM image.According to a hierarchy of Qinghai grassland productivity,level of grassland productivity Maduo County distribution map was obtained finally.The results showed that ①Maduo County NDVI mainly from 0 to 0.5,representing the total grassland area Maduo County,88.64%;②Correlation coefficient between monitor sampling point ground biomass and NDVI was significantly correlated,above 0.7.Model can be quantitatively expressed as： y=552.632×NDVI1.137;③The main grassland productivity level of Maduo County is 750-3 000 kg/hm2,72% of the total grassland area.The highest level of grassland productivity is 4 500-6 000 kg/hm2,but less than 1% of the total grassland area.