黄海和东海表层悬沙浓度年际变化特征  

Inter-annual variation of suspended sediment concentration in the surface waters of the Yellow Sea and East China Sea

作　　者：尹琦珺 高抒[1,2] 高明哲[1] 易家成 

机构地区：[1]南京大学地理与海洋科学学院,江苏南京210046 [2]南京大学海岸与海岛开发教育部重点实验室,江苏南京210046

出　　处：《海洋通报》2016年第5期494-506,共13页Marine Science Bulletin

基　　金：国家重大科学研究计划(2013CB956500);江苏省自然科学基金重点研究专项(BK2011012);南京大学大学生创新训练计划(XY1310284012)

摘　　要：运用547 nm反射率、海表温度和海表风场遥感数据,分析了黄、东海表层悬沙浓度的年际变化特征、影响因素和形成机理。研究区近岸海域表层悬沙浓度较高,远离陆地的海域悬沙浓度一般较低,且存在明显的季节变化,其季节变化的敏感区(变化较大的区域,其反射率差大于1%)为浑浊羽状流分布区域和近岸海域。该羽状流从江苏海岸向东偏南方向延伸至黄、东海陆架中部,其边界以4 mg/L表层悬沙浓度为标志,冬季最盛,夏季最弱,甚至消失。研究区表层悬沙浓度也存在明显的年际变化,其冬季敏感区为浑浊羽状流与朝鲜半岛之间的海域(即羽状流东北部)、台湾海峡、近岸海域、浑浊羽状流南部边缘;其夏季敏感区主要是近岸海域。悬沙浓度年际变化的幅度略小于季节变化。冬季黄海暖流和台湾暖流对浑浊羽状流的扩散起阻碍作用,二者基本框定了该季节浑浊羽状流的边界范围,其年际变化形成多年尺度上冬季表层悬沙浓度的敏感区。虽然风浪作用对悬沙浓度变化有影响,但不是影响年际变化的主要因素。研究区冬季浑浊羽状流的形成和扩展的变异是受陆架环流控制的,是表层悬沙向深海输运的重要因素。此外,对敏感区的平均海表温度与南方涛动指数(SO)I、太平洋十年涛动指数(PDO)I的相关分析结果表明,本区陆架环流的宏观格局受到了厄尔尼诺-南方涛动(ENSO)和太平洋十年涛动(PDO)的影响,而PDO的影响弱于ENSO。Remote sensing data of reflectance at 547 nm, sea surface temperature（SST） and wind are used to analyze the inter-annual variation of the suspended sediment concentration（ SSC） in the surface waters of the Yellow Sea and East China Sea, as well as the relevant factors and mechanism. In the study area, SSC in the surface waters tends to be higher in the coastal area than that in the open sea, with remarked seasonal variation. The sensitive regions, where the seasonal variation is most significant, are associated with a turbid plume or coastal water masses. The plume, defined by an SSC exceeding4 mg/L, extends from the Jiangsu coast towards the central areas of the Yellow Sea and East China Sea. It is strongest in winter, while in summer, it becomes weakest, or even vanishes. Further, the SSC also shows remarked inter-annual variations.In winter, the sensitive regions are located between the turbid plume and the Korean Peninsula, in the Taiwan Strait, over the coastal waters, and at the south margin of the plume. In contrast, the sensitive regions in summer are confined mainly in the coastal areas. The magnitude of the inter-annual variation is slightly smaller than that of the seasonal variation. The Yellow Sea Warm Current（YSWC） and the Taiwan Warm Current（TWC） block the diffusion of the turbid plume in winter. Theinter-annual variation of the YSWC and TWC leads to the variation in the diffusion range of the plume, forming sensitive regions in winter at the inter-annual time scale. Wind and wind waves do not represent major factors affecting the winter inter-annual variation. The formation and expansion of the turbid plume are controlled mainly by the continental shelf circulation, which influences the cross-shelf dispersal of fine-grained sediments. Furthermore, correlations of the SST field over the sensitive areas with the Southern Oscillation Index（ SOI） and the Pacific Decadal Oscillation Index（ PDOI）indicate that the overall pattern of the shelf circulation here is influenced by El N

关 键 词：悬沙浓度 年际变化 敏感区 输运过程 中国东部陆架 

分 类 号：P736[天文地球—海洋地质]