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遥感红边指数与表征绿色植物生长状况的重要生化参数有密切的关系,是植被长势监测的重要因子。为寻找出最适用于城市草地生长状况监测的红边指数,本文基于Sentinel-2A数据,对比分析了不同红边指数在城市草地健康状况估算方面的差异。本文以福州市和厦门市的城市草地为例,在全面分析各种健康水平草地光谱响应特征差异的基础上,选取了6种与草地生化参数相关的红边指数,即红边位置REP、地面叶绿素指数MTCI、归一化差值红边指数NDRE1、新型倒红边叶绿素指数IRECI、红边叶绿素指数CIred-edge以及叶绿素吸收指数MCARI2,然后采用独立样本T检验及欧式距离对这6种红边指数在草地健康判别中的优劣进行了定量对比。结果表明:IRECI指数对草地健康状况最为敏感,该指数在不同健康等级草地的值域区间和均值都存在显著性差异,其判别总精度均大于85%;NDRE1和MCARI2指数次之,其他3个指数则难以判别草地的健康状况。因此,在基于Sentinel-2A影像的城市草地健康遥感判别中,推荐使用IRECI指数。
The red edge index of remote sensing is closely related to the important biochemical parameters that characterize the growth status of green plants and is an important factor for vegetation growth monitoring. In order to find out the red edge index which is most suitable for the monitoring of urban grassland growth status, this paper comparatively analyzed the differences of different red edge index in the estimation of urban grassland health status based on the Sentinel-2A data. Taking the urban grassland in Fuzhou and Xiamen as an example, based on the comprehensive analysis of differences in spectral response characteristics of various grasslands, six red-edge indices related to grassland biochemical parameters were selected, that is, red edge position REP, Chlorophyll index MTCI, normalized difference red edge index NDRE1, new inverted red edge chlorophyll index IRECI, red edge chlorophyll index CIred-edge and chlorophyll absorption index MCARI2, and then using the independent sample T test and the European distance on the six kinds of red edge The index is compared quantitatively in the grassland health discrimination. The results showed that the IRECI index was the most sensitive to the grassland health status. There were significant differences in the range and mean values of grassland indices between different health grades. The accuracy of the index was greater than 85%. The index of NDRE1 and MCARI2 was the second and the other three Index is difficult to distinguish grassland health status. Therefore, it is recommended to use IRECI index in urban grassland health remote sensing based on Sentinel-2A images.