黄渤海水体光学性质变化及其影响机制

发布时间：2018-07-10 18:00

本文选题：光学性质 + 影响机制　；参考：《中国海洋大学》2015年博士论文

【摘要】：海洋水体光学性质的变化及其影响机制的研究对于建立高精度的水色遥感反演方法、利用光学手段监测悬浮颗粒物的动态变化、预测水下能见度的变化以及利用光学手段研究短时间尺度的海洋和天气过程对水体的影响具有重要的意义。本研究利用现场广泛测量的光学性质数据,深入认识黄渤海水体光学性质变化的时间(季节)和空间(水平及垂直)分布特征;并结合同步测量的水文及生物地球化学参数等数据所揭示的海洋过程分析了黄渤海水体光学性质季节和空间变化的主要影响机制：然后以影响机制为基础,定量化光学性质变化与水体光学活性组分的关系。在上述研究的基础上,利用在黄渤海广泛测量的光学数据研究了光学性质的光谱依赖性关系,并构建了黄渤海水体光学性质参数化模型。最后利用沙尘暴期间的定点周日测量分析了沙尘暴对水体光学性质的影响。主要研究结果如下：1.黄渤海水体光学性质变化主要由潮波所致的底部沉积物再悬浮、水体垂向混合及浮游植物生长的生物过程所影响。具体影响机制如下：春季,水体的垂向混合动力开始降低,层化现象开始出现,层化结构的出现进一步降低了水体的垂向混合动力,使得底部受潮波所致再悬浮的沉积物的上移受限,由于春季具备适宜浮游植物生长所需的条件,浮游植物得以开始大量生长,对于深水区,其上层水体的光学性质主要由浮游植物生长的生物过程所影响,其底层水体主要由潮波所致的底部沉积物的再悬浮过程所影响,对于浅水区,由于水深较浅,同等外部条件下,其垂向混合动力较之深水区较强,层化效应相对也较弱,底层再悬浮的沉积物较之深水区更易上移至上层水体,因此对于浅水区,上层水体的光学性质除受浮游植物生长的生物过程影响外,还受底部沉积物的再悬浮过程所影响。夏季,水体的层化效应得到进一步加强,黄渤海大部分水域的上层水体的光学性质主要由浮游植物生长的生物过程所影响。秋冬季节,水体层化效应减弱,垂向混合作用较强,深度小于50m的水体垂向混合慢慢均匀,对于深度大于50m的水域,由于水深较深,强混合作用仍不能使得水体上下混合均匀,但强混合作用使得上混合层深度较深,上混合层底部距海底较近,底部再悬浮的沉积物易通过跃层进入上混合层水体,但对于特别深的水体如黄海海槽附近水体,虽然上混合层底部距海底较近,但由于水深更深,跃层相对较强,底部再悬浮的沉积物依然很难突破跃层进入上混合层,因此对于秋冬季节,除黄海海槽附近水域上层水体的光学性质依然受浮游植物生物过程影响外,大部分水体的光学性质逐渐由底部沉积物的再悬浮过程所影响。2.直接引起黄渤海水体光学性质变化的主要光学活性组分是水体中的悬浮颗粒物。光学性质与悬浮颗粒物的关系依赖于悬浮颗粒物的类型,对于后向散射比大于0.015的水体,水体中的颗粒物主要以无机颗粒物为主,光学性质与悬浮颗粒物浓度具有较好的相关关系,平均相关系数约为0.97；对于后向散射比小于0.009的水体,水体中的颗粒物主要以浮游植物颗粒为主,其光学性质与叶绿素浓度具有较好的相关关系,平均相关系数约为0.87。3.对于春季南黄海中部上混合层水体,当沙尘暴发生时,沉降于水体的沙尘颗粒对散射的贡献取决于沙尘暴的强度,气溶胶光学厚度约为2.5的沙尘暴所引起的沙尘颗粒沉降导致的水体颗粒物散射系数在532nm处的增加量约为0.14m-1；此外,沉降于上混合层水体内的沙尘颗粒的沉降速度较快,伴随着沙尘暴的结束,约结束后的3个小时内,上混合层水体内的沙尘颗粒便沉降到底层：另外研究结果间接揭示出大气沉降对光学性质变化的影响在无沙尘暴发生时可近似认为0。
[Abstract]:The study of the changes in the optical properties of marine water and its influence mechanism is important for the establishment of high precision water color remote sensing inversion method, the use of optical means to monitor the dynamic changes of suspended particles, the prediction of the changes in underwater visibility and the influence of the ocean and weather processes on the short time scale by using optical means to study the water body. In this study, the time (season) and spatial (horizontal and vertical) distribution characteristics of the changes in the optical properties of the yellow and Bohai water bodies are thoroughly understood by using the optical properties of the widely measured field, and the seasonal and space of the optical properties of the yellow and Bohai water bodies are analyzed by the oceanic process revealed by the data of hydrologic and biogeochemical parameters measured synchronously. The main influence mechanism of inter change: then based on the influence mechanism, the relationship between the change of optical properties and the optical active components of water body is quantified. On the basis of the above study, the optical properties of the optical properties of the yellow and Bohai water body are studied by using the optical data widely measured in yellow and yellow Bohai, and the parameterized model of the optical properties of the Yellow River water body is constructed. Finally, the effects of dust storms on the optical properties of water bodies were analyzed using a fixed Sunday survey during the dust storm. The main results are as follows: 1. the changes in optical properties of 1. yellow water bodies are mainly influenced by the sediment resuspension caused by tidal waves, the vertical mixing of water bodies and the biological processes of phytoplankton growth. In the spring, the vertical hybrid power of the water body begins to decrease, and the stratification begins to appear. The emergence of the stratification will further reduce the vertical mixing of the water body, which makes the upshift of the sediment suspended from the bottom of the tidal wave limited. As a result of the conditions necessary for the growth of phytoplankton in the spring, the phytoplankton can start a large number of plants. For the deep water, the optical properties of the upper water body are mainly influenced by the biological process of the phytoplankton growth. The bottom water body is mainly influenced by the resuspension process of the bottom sediments caused by tidal waves. For shallow water, the vertical hybrid power is stronger than the deep water area and the stratification effect is stronger than that in the deep water area. In the shallow water, the optical properties of the upper water body are affected by the biological process of phytoplankton growth and the resuspension process of the bottom sediments. In the summer, the stratification effect of the water body is further strengthened, and the large part of the Yellow Bohai region. The optical properties of the upper water body in the sub waters are mainly influenced by the biological process of the phytoplankton growth. In the autumn and winter season, the effect of the water layer is weakened, the vertical mixing is stronger, the vertical mixing of the water body with depth less than 50m is slowly uniform. For the waters with depth greater than 50m, the strong mixing can not make the water mixing up and down because of the deep water depth. It is uniform, but strong mixing makes the upper mixing layer deep, the bottom of the upper mixing layer is closer to the bottom of the sea, and the bottom suspended sediment is easy to enter the upper mixed layer water through the levitate layer, but for the special deep water body, such as the water in the Huang Haihai trough, although the bottom of the upper layer is closer to the bottom of the sea, the depth of the water is deeper and the cline is relatively stronger. In the autumn and winter, the optical properties of the upper water body in the waters near the Yellow Sea and sea trough are still affected by the biological process of phytoplankton in the autumn and winter seasons. The optical properties of most water bodies are gradually influenced by the resuspension process of the bottom sediments by.2. directly caused by the Huang Bo sea water. The main optical active components of the changes in the optical properties of the body are suspended particles in the water body. The relationship between the optical properties and the suspended particles depends on the type of suspended particles. For the water body with a backscatter ratio greater than 0.015, the particles in the water body are mainly inorganic particles, and the optical properties and the concentration of suspended particles are better. The correlation coefficient is about 0.97, and for the water body with the backscatter ratio less than 0.009, the main particles in the water body are mainly phytoplankton particles, and the optical properties have a good correlation with the chlorophyll concentration. The average correlation coefficient is about 0.87.3. for the upper mixed layer water in the middle of the South Yellow Sea in spring, when the dust storm occurs. The contribution of sand dust particles settling in water to the scattering depends on the strength of dust storm. The increase of the scattering coefficient of particles in the 532nm is about 0.14m-1, and the sedimentation rate of sand particles in the water body of the upper mixing layer is more than that of the dust particles. Fast, with the end of the dust storm, the dust particles in the upper mixed layer of water will settle down to the bottom within 3 hours after the end of the end. The results indirectly reveal that the effect of atmospheric deposition on the change of optical properties can be approximately 0. in the absence of dust storms.
【学位授予单位】：中国海洋大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P733

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