基于走航观测的长江口邻近海域悬浮颗粒物高频变化研究

High-Frequency Variation of Suspended Particle Matter in Sea Area Adjacent to Yangtze Estuary Based on Underway Observation

基于2018年5月27日—31日长江口邻近海域的海洋科学综合调查,利用船载走航式表观光谱观测系统进行了定点及连续光谱测量,结合快速多参数水质仪和声学多普勒流速剖面仪同步观测结果,研究了悬浮颗粒物(SPM)的高频变化特征及其影响因素。研究结果表明,长江口邻近海域SPM浓度存在高频变化特征,且受潮汐作用影响显著。在退潮周期内,其浓度在定点站位内有明显的先上升后下降过程,且浓度高值与高流速相对应。断面走航观测显示,SPM在短时间内变化特征存在明显的空间差异。在水深较浅的区域中局地再悬浮过程的作用明显,且SPM浓度与流速之间有着良好的对应关系,而在水深较深、离岸较远的区域中SPM浓度的变化则可能与长江冲淡水过程相关。

Based on a comprehensive marine scientific survey conducted in the sea area adjacent to the Yangtze Estuary from May 27 to May 31,2018,a fixed point and continuous spectrum observation with the ship-based underway apparent spectrum observation system is carried out.Simultaneous observation results of a rapid multi-parameter water quality meter and an acoustic Doppler current profiler are also incorporated to study the high-frequency variation of the suspended particulate matter(SPM)and its influencing factors.The results show that the SPM concentration in the sea area adjacent to the Yangtze Estuary demonstrates high-frequency variations and significant influence by the tide.During the ebb period,the SPM concentration at the fixed station distinctly increases first and then decreases,with high value corresponding to the high current velocity.Underway transect observation results exhibit obvious regional differences in the variation characteristics of the SPM in a short time.In a shallower area,the local resuspension process plays a dominant role,with a close relationship between SPM concentration and the current velocity.In contrast,the concentration variation of the SPM in farther offshore areas with deeper depth may be related to the Yangtze River diluted water process.