基于光谱特征的MODIS影像东海水体类别信息提取

Water Class Extraction of the East China Sea Using MODIS Data Based on Spectral Characteristics

近年来东海海洋环境由于赤潮频发日趋恶化,为了进行基于水体类别信息提取的水体宏观分异规律探究,本文在对不同水体光谱曲线分析的基础上,提出了两种基于光谱特征波段运算的MODIS影像水体类别提取模型,通过优化并确定各类水体阈值,最终得到了2004年6月11日和2007年10月2日东海赤潮期悬浮泥沙水体、富营养化水体、赤潮水体、赤潮边界水体和远洋洁净水体五大类的分布和变化特征,并分别对两个时期的影像进行了叶绿素a(Chl-a)和海表温度(SST)反演辅助分析,研究结果不仅能从宏观上有效识别悬浮泥沙和赤潮等水体的分布范围,同时也能反映出不同水体因子从海岸带向远洋深海的变化规律,为海洋环境进一步探讨提供了研究基础。

In recent years the marine environment in the East China Sea（ECS） tends to become deteriorated because of frequent algal blooms.In order to detect the microscopic distribution of ocean waters based on the classification extraction,efforts are firstly made in this paper to analyze the spectrums of each water class,and then two bands-ratio classification algorithms based on spectral characteristics are developed.After the optimization of the threshold values,distribution and variation characteristics of suspended sediment water,eutrophication water,algae bloom water,boundary water of algae bloom,and open ocean water are obtained from the MODIS L1 data respectively on Jun 11th,2004 and Oct 2nd,2007 when algal blooms broke out.Besides,Chlorophyll a（Chl-a） and Sea Surface Temperature（SST） derived from the same original data are analyzed as ancillary information.This result not only can identify the distribution of different waters but also reveal the changing pattern of water factors from the coastline to the open ocean,providing the baseline for future discussion of the marine environment in ECS.