2014年春季南海中沙群岛北部海域的低温高盐水及其形成机制  

The formation mechanism of the low temperature and high salinity water mass near the Zhongsha Islands in the South China Sea in March 2014

作　　者：田永青[1,2] 黄洪辉[2] 巩秀玉[2] 余少梅[2] 

机构地区：[1]国家海洋局第三海洋研究所,福建厦门361005 [2]广东省渔业生态环境重点实验室中国水产科学研究院南海水产研究所,广东广州510300

出　　处：《热带海洋学报》2016年第2期1-9,共9页Journal of Tropical 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2013035);农业部财政重大专项(NFZX2013);海洋公益性行业科研专项(201005005-2);"全球变化与海气相互作用"专项(GASI-03-01-01-03);中国科学院战略先导科技专项(XDA1102030104);科技基础性工作专项(2008FY110100)~~

摘　　要：分析了2014年3月南海中部调查航次的温盐数据,发现在中沙群岛北部海域存在一显著的低温高盐水团,在表层(5m)低温水体核心仅25℃,比周边测站至少低1℃,高盐核心值达34.11‰,比周边站位至少高0.74‰。该水体影响范围水平上约1个经度×1.5个纬度,垂直深度仅在30m以浅,持续时间约13d。结合地形、卫星高度计和风场数据,揭示该水团的生消过程及动力机制:3月初吕宋冷涡系统脱落出一个强的中尺度冷涡往西传播,遇到陆架区(115?E,18?N附近)发生停滞和形变,其南部边缘则在地形和风场的诱导下,再次脱落出一个小的气旋涡,即观测到的低温高盐水团,并沿3000m等深线向南传播至中沙群岛附近海域。该水团的消失是由于3月29日至4月初东北风转为偏南风,偏南风加速了南部暖水与低温高盐水团的混合变性,并最终使得该水团消亡。Based on the analysis of temperature and salinity survey data in the central South China Sea (SCS) in March2014, we found that there existed a notable low temperature and high salinity water mass in the northern Zhongsha Islands. The core temperature of the water mass was only 25℃ in the surface layer (5 m), which was lower than that at the surrounding stations by at least 1℃, and its core salinity was 34.11 psu, which was higher than that at the surrounding stations by at least 0.74 psu. Furthermore, the water mass had influence on an area of about 1 longitude by 1.5 latitude, just 30 m from the sea surface, and it could last approximately for 13 days. Combining with the topography data, satellite altimeter data and wind data, we demonstrated the forming and decaying processes and dynamic mechanisms of the water mass. In early March, a strong mesoscale cold eddy shed from the Luzon cold eddy system and propagated to the west; it stagnated and deformed when encountering the continental shelf at about 115°E, 18°N. However, under the induction of topography and wind, the southern edge of the strong mesoscale cold eddy shed a small cyclonic eddy again, namely, the low temperature and high salinity water mass that was observed. The water mass propagated to the Zhongsha Islands area around the 3000m isobath. The water mass vanished owing to the wind direction change from the northeasterly on March 29to the southerly at the beginning of April. The southerly wind accelerated the mixing between the southern warm water and the low temperature and high salinity water mass, and then the low temperature and high salinity water mass disappeared at last.

关 键 词：中沙群岛 吕宋冷涡 东北季风 低温高盐水 中尺度涡 

分 类 号：P731[天文地球—海洋科学]