草原关键生育期遥感模式与信息提取方法

Remote Sensing Monitoring for the Key Phonological Stages of Rangeland A Case Study about Xilingol Grassland

利用2005年中分辨率光谱辐射仪(MODIS)数据,提取植被指数(NDVI)数据集,并定义、提取内蒙古锡林郭勒盟草原4种草地类型(草甸草原、典型草原、沙地草原和荒漠草原)的关键生育期。通过与生育期观测资料对比来评价应用NDVI数据集识别和预测不同草地类型出现返青期和成熟期的能力。研究结果表明,在锡林郭勒草原,利用NDVI的旬度变化可以鉴别出2个关键生育期(返青期和抽穗期)。遥感估测结果与地面观测和历史资料比较接近,说明10 d合成250 m分辨率NDVI数据集可以用来监测草原生育期。

Two key phenological stages, turning green and heading, of four rangeland types were defined primarily based on Terra/MODIS-NDVI time series data collected from 2005. The results show that the satellite-derived data were proved to be consistent with the ‘green wave’ moving through the rangeland in spring. The turning green stage of meadow grassland and typical grassland recorded by satellite was in the 14thdecad, the 15thdecad for desert grassland, and the 13thdecad for sand grassland. The heading stage of the four grassland types recorded by satellite was all in the 23th decad. The results closely correlated with temperatures and precipitation. Comparisons between remote sensing results and ground phenological observations as well as historic data confirmed the coherence of satellite-derived phenology data.