渤海和北黄海水色光谱的特征分析

Characteristics of Ocean Color Spectrum in Bohai Sea and Northern Yellow Sea

我国的主要海域包括渤海、黄海、东海的大部分和南海的近岸部分都属于二类水体,这些海域的光学特征极为复杂.针对不同海域的海洋光学特征进行研究,对于反演二类水体叶绿素、悬浮泥沙和黄色物质的浓度具有非常重要的意义.本文利用渤海和北黄海海域2002年11月至2003年8月的水色调查数据,对调查海区的水色光谱的特征进行了研究和分析.结果显示调查海区的水色光谱类型主要分为4个类型:类型1的主要特点是光谱峰值位于570 nm,谱峰比较窄,随波长远离谱峰波段,遥感反射率迅速减小,主要分布海域为渤海湾、莱州湾及辽东湾.类型2的光谱峰值位于550nm左右,谱峰比较宽,随波长增大,遥感反射率迅速减小,主要分布在渤海中部海区.类型3光谱峰值位于500～550 nm范围内,440nm存在极小值,主要分布在渤海海峡和渤海中北部的一块海域.类型4类似于大洋一类水体的水色光谱,其特点是在可见光波段内,随波长增大,遥感反射率逐渐减小,主要分布在渤海海峡以外、远离海岸的北黄海海域.

Bohai Sea, Yellow Sea, the majority of Donghai Sea and the coastal zone of South China Sea are all Class Ⅱ waters, where the optical characteristics are very complicated. Studying the ocean optical characteristics in different sea areas is very important to deduce Chl-a concentration, suspended sediment concentration and CDOM concentration of Class Ⅱ waters. In this paper, using the in-situ measured data observed from November 2002 to August 2003, we analyse and study the ocean color optical spectrum of Bohai Sea and Northern Yellow Sea. The result shows that there are four types of color optical spectrum in the observed sea area. The spectrum peak value of type one locates at 570 nm, the width of spectrum peak is narrow, and the reflectance is lessening rapidly when the wavelength is bigger or smaller than 570 nm. Spectra of type one are mainly distributed in the Bohai Bay, Laizhou Bay and Liaodong Bay. The spectrum peak value of type two locates at 550 nm, the width of spectrum peak is wide, and the reflectance is lessening when wavelength is bigger than 550 nm. Spectra of type two are mainly distributed in the central sea area of Bohai Sea. Spectra of type three are mainly distributed in the Bohai channel. The spectrum peak value of type three locates at 500-550 nm, and a minimum occurs at 440 nm. Type four is similar to the spectrum of Class I waters, the reflectance is reducing when the wavelength is increasing in the visible light wave band. Type four is mainly distributed in the Northern Yellow Sea area which is far away from the seacoast.