收稿日期: 2009-05-06
修回日期: 2009-12-15
网络出版日期: 2010-03-23
基金资助
中国科学院知识创新工程重要方向项目(KZCX2-YW-215); 国家863计划(2006AA09A310); 国家自然科学基金项目(40906021,
4090622,U0933005); 中国科学院南海海洋研究所青年人才领域前沿项目(SQ200812)
Variations of absorption coefficient of seawater in the Pearl River Estuary and a hyperspectral retrieval model for an algal bloom
Received date: 2009-05-06
Revised date: 2009-12-15
Online published: 2010-03-23
基于2007年8月海洋光学浮标在珠江口投放期间获得的近16天的实测生物光学数据, 对一次藻华过程中水体总吸收系数和水色光谱的变化特性及其相互关系进行了研究。结果表明, 藻华前后水体中非藻类物质尤其是有色溶解有机物在蓝光波段具有较强的吸收贡献, 而当藻华爆发时, 随着叶绿素a浓度的急剧增大, 浮游植物的吸收贡献明显增强; 各波段之间总吸收系数呈现出较好的线性相关关系, 吸收光谱蓝绿波段比值的变化对遥感反射率的光谱分布有重要的贡献; 据此建立了对水体总吸收系数反演的经验关系模型, 表现出较高的反演精度, 计算值与实测值之间相对偏差的均方根在可见光波段可控制在24%以内。
王桂芬,曹文熙,杨跃忠,周雯,梁少君, . 珠江口藻华水体总吸收系数的变化特性及高光谱反演模式[J]. 热带海洋学报, 2010 , 29(2) : 52 -58 . DOI: 10.11978/j.issn.1009-5470.2010.02.052
In August 2007, bio-optical measurements were collected over a period of 16 days in the Pearl River Estuary, and an algal bloom was detected. In situ radiometric data were obtained using a marine optical buoy. The variations in absorption properties and ocean color of seawater and their internal relationship were investigated. The results show that the colored detrital matter (CDM), especially the colored dissolved organic matter (CDOM), had large contributions to the total absorption of seawater at blue waveband, while the absorption contribution of phytoplankton tended to increase with the rapid increase of chlorophyll a concentration when the bloom occurred. Linear regression was used to express the spectral correlations between total absorption coefficients at 443nm and at other visible bands, and the blue-to-red ratio of absorption showed a big effect on the spectral distribution of spectral reflectance. An empirical hyperspectral ocean color model for retrieving the absorption coefficient was developed, and the calculated and measured results showed small discrepancy, with relative root mean square error being less than 24% over the visible spectrum.
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