2002年夏季南海东北部陆架海域的低盐透镜现象分析  

Low salinity lenses in the northeastern shelf of the South China Sea and their possible formation mechanism in summer,2002

作　　者：靖春生[1] 黄奖[1] 郭小钢[1] 

机构地区：[1]国家海洋局第三海洋研究所,福建厦门361005

出　　处：《应用海洋学学报》2013年第2期148-155,共8页Journal of Applied Oceanography

基　　金：国家海洋局第三海洋研究所基本科研业务费专项资金资助项目(海三科2008014);国家自然科学基金资助项目(40876014);国家重点基础研究发展计划资助项目(2011CB403502)

摘　　要：低盐透镜现象是夏季南海东北部陆架海域一种常见的中尺度现象.低盐透镜水体往往是由陆地径流入海后与河口冲淡水母体分离而形成的.它携带大量的陆源物质会对海洋生态环境造成较大的影响.通过对2002年7～8月南海东北部海域的现场CTD调查资料的分析,发现在西南季风盛行的夏季,南海东北部陆架区近岸一侧上升流现象非常明显,呈低温高盐水的特征,而在离岸约100 km处存在着相对独立的低盐透镜水体.此类水体的盐度在32.5以下,水平宽度约为80 km,仅存在于20 m以浅的海洋上层.结合同期的现场走航ADCP测流资料、珠江径流量和海面风场资料分析后认为该水体源自珠江冲淡水;海面风场、上层海流及潮汐潮流等的共同作用可能是脉冲的珠江洪峰与珠江河口冲淡水母体分离而形成低盐透镜现象的动力学原因.沿岸的上升流系统与低盐透镜水体之间形成温度和盐度锋面.Low salinity lens is a meso-scale phenomenon in the northeastern South China Sea in summer. It came from the river discharge, and was separated from the river plume by some dynamic factors. The low salinity lens waters with land-source materials could influence the local marine environment significantly. The investigation shows that relatively isolated low salinity lens waters with salinities lower than 32. 5 were found in the upper 20m levels in the sea 100 km off the coastline in June and July of 2002, with a horizontal diameter of about 80kin. The forming mechanism of the low salinity waters were discussed by analyzing the ADCP in situ data, the Pearl River discharge, sea surface wind and currents. It was suggested that the Pearl River pulsing fresh water was possibly detached by the coactions of the variable sea surface winds, the surface currents and the tide. Temperature and salinity fronts were formed between the coastal upwelling and the low salinity lens waters.

关 键 词：物理海洋学 低盐透镜现象 水温 盐度 入海径流 珠江冲淡水 南海 

分 类 号：P731[天文地球—海洋科学]