水库水体近红外反射峰与叶绿素含量之间的关系初探-湖泊科学.PDF

J. Lake Sci.(湖泊科学), 2009, 21(2): 228-233 . E-mail: jlakes@ ©2009 by Journal of Lake Sciences 水库水体近红外反射峰与叶绿素含量之间的关系初探∗ 杨 敏, 商少凌**, 汪文琦, 林 供, 王郝京 (厦门大学近海海洋环境科学国家重点实验室, 厦门 361005) 摘 要: 2007 年 8 月至 2008 年 9 月, 对厦门两个淡水水体(芙蓉湖、厦大水 )的叶绿素浓度和遥感反射率(Rrs)进行了连续观 测. 在叶绿素浓度 6-322mg/m3 的范围, Rrs 光谱出现显著的近红外反射峰, 中心位置在 700-710nm 之间, 较之通常的荧光峰中 心(683nm) 向长波方向偏离. 该峰在厦大水库始终出现在 700nm, 但在芙蓉湖存在时间变化, 随着叶绿素浓度的增加, 由 705 红移到 710nm. 由此, 仿 MODIS 荧光高度(FLH)的定义, 定义该峰的高度(简写为 REH), 对于水库和芙蓉湖中心波段分别确定 为 700 和 710nm. REH 与叶绿素浓度呈现显著相关, 芙蓉湖 REH=0.016lg(chl)-7.8 ×10-6 2 (R =0.79, n=41), 水 REH=0.0001chl+ 2 0.0002(R =0.74, n=32). 可见对于高散射的淡水藻华水体, 可以并且需要通过改进 FLH 的波段选择, 基于更长波段处的近红外 峰的高度探测叶绿素浓度. 关键词: 近红外反射峰; 叶绿素; 遥感反射率; 淡水 The NIR peak of the reflectance spectrum associated with chlorophyll in the pool waters: preliminary results YANG Min, SHANG Shaoling, WANG Wenqi, LIN Gong WANG Haojing (State Key Laboratory of Marine Environmental Science, Xiamen University , Xiamen 361005, P.R.China) Abstract : Remote sensing reflectance (Rrs) and concurrent chlorophyll-a (Chl) concentration were measured from August 2007 to September 2008 in two pools (Furong Pool and XMU Reservoir) in Xiamen, Fujian. During most of the time, the measured Rrs spectra for Chl ranging between 6 to 322mg/m3 show a prominent secondary peak in the far-red region of the spectrum. This is not from fluorescence alone, but appears to be caused by the red edge. Following the estimation of MODIS Fluorescence line height (FLH), we defined a red edge height (REH) during 705 and 710nm. It was found that REH was