基于不同植被指数的天山北坡草地返青期遥感监测初探

Preliminary Study on Remote Sensing Monitoring of Grassland Returning Green Period in the North Slope of Tianshan Mountain Based on Different Vegetation Indexes

草原返青期做为草原植被物候期的始期,掌握返青期的动态变化情况,对于了解草原生态系统全年的情况具有重要意义。为探究不同植被指数反映草原植被返青情况的效果,本文以天山北坡不同草地类为研究对象,结合地面观测点数据,根据草原植被物候期的发展规律,使用MYD13Q1(16 d,250 m×250 m分辨率)数据,并对数据中的NDVI、EVI、红外波段、近红外波段分别进行镶嵌、重采样、加投影等预处理过程,随后进行波段运算处理,得出不同的植被指数,再利用ArcGIS软件进行空间分析处理,以遥感的方式反演出地面监测点的返青情况。结果表明,利用植被指数对天山北坡的温性荒漠类草地进行监测得出的结果与地面监测结果一致,利用光谱指数对温性荒漠类草原植被的返青期监测是一种可行的方法,其他草地类的遥感监测还需进一步的研究。

The returning green period is the beginning of phenological period of grassland, and it is of great significance to master the dynamic changes of the returning period for understanding the situation of grassland ecosystem throughout the year. In order to explore the effect of different vegetation indexes on reflecting the regreening, different types of grassland on the northern slope of Tianshan Mountain were taken as the research object, according to the development law of phenological period, combined with the data from ground observation points and MYD13Q1(16 d, resolution of 250 m×250 m), the NDVI, EVI, infrared band and near infrared band from the data were preprocessed by methods of mosaic, resampling and projection, etc. Then different vegetation indexes were obtained by band calculation processing, at last, the regreening of grassland in ground monitoring points was reversely deduced by remote sensing with using ArcGIS software to perform spatial analysis. As a result, the results obtained by monitoring the temperate desert grassland on the northern slope using the vegetation indexes were consistent with those of ground monitoring points, therefore, it was a feasible method to monitor the returning green period of grassland vegetation in temperate desert using spectral indexes. Remote sensing technologies for monitoring other types of grassland needed further research.