底边界层水沙观测系统和应用  

Application of instrumented tetrapod in bottom boundary layer for water-sediment measurement

作　　者：徐俊杰[1] 何青[1] 王元叶[1,2] 

机构地区：[1]华东师范大学河口海岸学国家重点实验室,上海200062 [2]交通部上海河口海岸科学研究中心,上海201201

出　　处：《海洋工程》2009年第1期55-61,共7页The Ocean Engineering

基　　金：国家自然科学基金创新团队资助项目(40721004);973课题(2008DFB90240);上海市科委重大基础资助项目(07DJ14003-01)

摘　　要：利用现代先进的光学和声学测量仪器（ADP、PC．ADP、ADV、OBS等），组制四角架观测系统用于底边界层的水沙观测。此观测系统既可获取垂向流速场，更可获取常规水文观测难以获取的高分辨率的近底流速、近底单点紊动过程、近底温盐沙和波浪过程。利用此观测系统于2007年8月在长江口北槽最大浑浊带内进行了实地观测。分析四角架观测数据与同步船测底部数据表明，四角架观测系统在近底（特别是底部明显分层）观测时表现出明显优势。常规水文观测测得底部含沙量一般只相当于距底70-120cm高度含沙量；船测底部最大含沙量为5．8kg／m^3，而架测距底30em处最大含沙量有25kg／m＆3；近底含沙量较高时往往出现强分层，强分层时实测距底30cm处含沙量可达距底120cm处含沙量的5倍；船测底部流速比架测距底30cm处流速平均偏大45％；但距底30cm处最大流速仍可达1．2m／s。船测数据也验证了四角架观测数据的正确性。Several modern advanced optical and acoustic survey instnanents （ADP, PC-ADP, ADV, OBS, etc. ） have been fixed in a tetrapod for water-sediment measurement in bottom boundary layer. Vertical velocity profile as well as near bottom high resolution velocity, turbulence, temperature-salinity-sediment and wave process, which can＇t be easily obtained by routine hydrological survey, can be got by the tetrapod. It was deployed in the most turbid area of the north passage of the Yangtze estuary in August 2007. The data obtained from the tetrapod are com- pared with those from a survey vessel. The results show that the tetrapod system has great advantages in near bottom survey （especially the near bottom area is strongly stratified）. Bottom suspended sediment concentration （SSC） got by the vesselis approximate to that between 70 and 120 cm above （cmab） bottom. Maximum SSC obtained by the tetrapod is 5.8 kg/m^3 while maximum SSC at 30 cmab obtained by the tetrapod is 25 kg/m^3. Strong stratification usually occurs when bottom SSC is high. At that time, SSC at 30 cmab can be 5 times larger than that at 120 cmab. Bottomvessel measured velocities are averagely 45 % larger than those at 30 cmab. But maximum velocity at 30 cmab can still reach 1.2 m/s. Tetrapod data validity is also proved by the data from the vessel and data types are introduced and explained.

关 键 词：四角架 底边界层 泥沙 流速 长江口 

分 类 号：TV148.1[水利工程—水力学及河流动力学]