台湾海峡及周边海域水色光谱特性分析

Analysis on the characteristics of ocean color spectra in the Taiwan Strait and its surrounding area

利用2006—2007年4次908计划ST06区块海洋光学调查的数据和MODIS水色遥感数据,对台湾海峡及周边海域的水色光谱特性进行了研究和分析。结果显示该海域的水色光谱主要有4个类型:类型1光谱峰值出现在580 nm附近,谱峰两侧遥感反射率随波长变化迅速减小,主要分布在紧靠中国大陆的海域;类型2光谱峰值出现在540～560 nm之间,具有谱峰宽的特点,主要分布在台湾海峡靠近大陆的一侧;类型3光谱与大洋水体光谱类似,主要分布在台湾西南的南海区域和吕宋海峡区域;类型4光谱在.450 nm附近出现极小值,在500～600 nm之间出现峰值,主要出现在台湾海峡中部和靠近台湾岛的一侧。其中类型2和4水体分布具有明显的季节特征。类型3、4、2、1对应的叶绿素a浓度和悬浮泥沙浓度呈上升趋势,对应的透明度依次降低,该海域以二类水体为主。

The characteristics of ocean color spectra in the Taiwan Strait and its surrounding area are analyzed by the in- situ data from four oceanic optical investigations carried out from 2006 to 2007 and the satellite remote sensing data from MODIS. The results show that there are four types of color optical spectra in this area. The spectrum peak value of type 1 locates near 580nm. Its reflectance reduces rapidly when the wavelength is bigger or smaller than 580 nm. Spectra of type 1 are mainly distributed in the narrow area along the China coast. The spectrum of type 2 has the characteristics of wide spectrum peak, with the peak at 540-560 nm. Spectra of type 2 are mainly distributed in the western Taiwan Strait ,the area closer to China Mainland. Spectra of type 3 resemble those of the open ocean, mainly distributed over the South Chi- na Sea area to the southwest of Taiwan and the Luzon Strait area. Spectra of type 4 are mainly distributed in the middle and eastern Taiwan Strait. Its spectrum peak value locates at 500-600 nm,with a minimum at 450nm. The distributions of type 2 and type 4 have remarkable seasonal variability. The concentrations of ehlorophyll-a and suspended sediment in- crease and the transparency decreases with type number 3,4,2,1. The waters in this area are mainly case-II waters.