水生植被是湿地生态系统的核心, 也是影响湿地生态系统功能的最主要因素。 近年来, 卫星遥感技术在湿地植被资源调查、 分类和保护等领域中已得到广泛的应用。 由于水生植被独特的生长环境, 其冠层光谱会受到水体背景要素包括大气—水界面、 水中浮游生物以及泥沙含量、 透明度、 水体深度、 底质和其他光学活性成分的影响, 因此遥感技术应用于湿地水生植被冠层光谱研究时, 需考虑到水生植被不同于陆生植被的生长环境, 这一点在以往的相关研究中并没有得到应有的重视。 以典型的挺水植物鸢尾(Iris tectorum Maxim)为研究对象, 模拟湿地水生植被的生长环境, 使用地物光谱仪测定了鸢尾植被冠层在不同水深梯度背景下的光谱反射率(400~2 400 nm)。 实验结果表明, 背景水深与鸢尾冠层反射率之间存在着显著的负相关性, 其中可见光波段绝对相关系数在0.9以上, 近红外波段的绝对相关系数在0.8以上。 在可见光和近红外波段, 随着背景水深的增加, 鸢尾冠层反射率下降均比较明显。 最后分别依据可见光和近红外区域相关性最高的波段(505, 717, 1 075和2 383 nm)建立了背景水深与冠层反射率之间的线性方程, 并得出了相关参数。

Aquatic vegetation is the core of the wetland ecosystem, and it’s also the main factor influencing the wetland ecosystem functions. In recent years, satellite remote sensing technology has been widely used in the investigation, classification and protection fields of wetland vegetation resources. Because of its unique growth environment, aquatic vegetation, the canopy spectrum of aquatic vegetation will be affected by water background elements including air-water interface, plankton in the water, sediment content, transparency, water depth, sediment, and the other optically active ingredients. When the remote sensing technology for wetland aquatic vegetation canopy spectral studies, should be considered the growth environment differences between aquatic and terrestrial vegetation. However, previous studies did not get the attention it deserves. This paper choose a typical water plant (Iris tentorium Maxim) as the research object, simulate the growth environment of wetland aquatic plants, use the feature spectrometer measurements the spectral reflectance of Iris tentorium Maxim vegetation canopy under different water depth gradient background (400~2 400 nm). Experimental results show that there is a significant negative correlation between background water depth and Iris canopy reflectance. Visible light band absolute correlation coefficient is above 0.9, near infrared band absolute correlation coefficient is above 0.8. In visible light and near infrared band, with water depth increases, the Iris canopy reflectance decreases obviously. Finally based on the highest correlation band of visible light and near infrared region (505, 717, 1 075 and 2 383 nm) established the linear equation between background water depth and the canopy reflectance, obtained the related parameters.