基于高分五号卫星数据的红树林群落光谱特征分析

Spectral Characteristics Analysis of Mangrove Community Based on Gaofen-5 Satellite Data

为解决高分五号(GF-5)高光谱数据空间分辨率较低的问题,本研究采用葛拉姆-施密特(Gram-Schmidt,GS)正交变换融合算法对GF-5高光谱数据与高分二号(GF-2)数据进行空谱融合,利用1 m分辨率的GF-5高光谱数据结合实地样本数据提取不同红树林群落与互花米草群落的平均反射率,通过包络线去除与一阶微分计算的方法分析不同红树林群落与互花米草群落的复合光谱特征,从光谱特征探讨红树林群落的可分性。结果表明,在原始光谱曲线680-900、980-1320、1530-1750 nm区间4种群落的光谱差异最大;经过包络线去除与一阶微分计算后的4种群落的光谱反射率分别在1170-1400 nm与1330-1470 nm波长范围处表现出明显差异。综上可知,不同红树林群落与互花米草的光谱反射率在近红外波段范围内的差异性最大,近红外波段可作为识别不同红树林群落与互花米草的优势波段。

In order to solve the problem of low spatial resolution of GF-5 hyperspectral data,Gram-Schmidt(GS)orthogonal transformation fusion algorithm was used to carry out spectral-spatial fusion between GF-5 hyperspectral data and GF-2 data.The average reflectance of different mangrove communities and Spartina alterniflora communities was extracted by using GF-5 hyperspectral data with 1 m resolution combined with field sample data.The composite spectral characteristics of different mangrove communities and S.alterniflora communities were analyzed by envelope removal and first-order differential calculation.The separability of mangrove communities was discussed from the spectral characteristics.The results showed that the spectral differences between the four communities were the greatest in the original spectral curves of 680-900,980-1320 and 1530-1750 nm.After envelope removal and first-order differential calculation,the spectral reflectance of the four communities was significantly different in the wavelength range of 1170-1400 nm and 1330-1470 nm,respectively.In summary,the spectral reflectance of different mangrove communities and S.alterniflora is the most different in the near-infrared band range,which can be used as the dominant band to identify different mangrove communities and S.alterniflora.