赤潮生消过程中的水体固有光学性质分析

Analysis of Inherent Optical Properties in the Occurrence and Declination of a Red Tide

在珠江口海域海洋光学浮标实验中获取一次聚生角毛藻赤潮生消过程的水体光学数据和相应的生化数据。利用该数据,分析了赤潮生消过程中水体光谱吸收和后向散射等光学性质的时间序列变化。研究发现,在赤潮生消过程中,浮游植物色素、非藻类颗粒物以及黄色物质等水体组分吸收变化显著,赤潮爆发期各组分光谱吸收增强并达到最大值,赤潮消亡期各组分光谱吸收降低并至最小值;赤潮爆发期与赤潮发展和消亡期相比,浮游植物的光谱吸收贡献增加约16%,黄色物质的吸收贡献减小约18%,而非藻类颗粒物的吸收贡献变化不大;赤潮爆发期后向散射系数明显增大,日变化幅度大,赤潮发展期和赤潮消亡期后向散射系数较小,赤潮消亡期后向散射系数降至最低;颗粒物后向散射系数与叶绿素a浓度的相关性优于悬浮物浓度。有机颗粒物浓度虽然在总颗粒物浓度中占主导地位,但是颗粒物后向散射与无机颗粒物的相关性更高。

During optical buoy experiments in the Pearl River （Zhujiang） mouth regions, time series of bio-optical data of Chaetoceros socialis red tide is obtained. By using the data, variation of ocean optical properties （absorption and backscattering properties） in the occurrence and declination of red tide is analyzed. Results show that the absorption of various components such as phytoplankton pigments, detritus and colored dissolved organic matter changes dramatically, the absorption of various components increases and reaches maximum values in red tide outbreak period, then the absorption of various components decreases and reaches minimum values in red tide declination period. Compared with red tide development and declination period, contribution of phytoplankton pigment increases by 16 %, and that of colored dissolved organic matter decreases by 18 %, but that of detritus has little changes for red tide out break period; backscattering coefficient increases in red tide outbreak period, and range of diurnal variation is large, backscattering coefficient is small in red tide development and declination period, and the value is minimum in red tide declination period. Correlation coefficient between backscattering coefficient and chlorophyll-a concentration is larger than that between backscattering coefficient and suspended matterconcentration. Although concentration of particulate organic matter in the total suspended particulate matter dominates, correlation coefficient between the backscattering coefficient and particulate inorganic matter concentration is larger.