【作者】 齐继峰；

【导师】 尹宝树；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 物理海洋学， 2014， 博士

【摘要】 东海水团的消长过程、台湾暖流水的季节变化、东海黑潮流量的变异以及东海陆架水交换过程，这些都是影响东海海洋环境状况、物质和能量输运的关键过程。因此，对这些关键海洋现象及其机制进行系统的研究具有重要的科学意义。本文基于大量的历史观测资料和数模结果，对东海相关海洋现象的演变机制进行了系统研究；利用实测温、盐资料研究了东海水团的季节变化特征，并从动力学和热力学的角度分析其变化机制，并在水团分析的基础上，结合数模结果，探讨了台湾暖流水的体积及其来源的季节变化特征；利用日本气象厅近50年来PN断面的观测资料，研究了东海黑潮流量的年际和年代际变化特征，并讨论了它与太平洋年代际振荡（PDO）和经向风异常的关系；利用高分辨率的数值模式ROMS模拟了东海气候态的环流系统，并分析了东海各主要水道的水量、热量和盐量输运的季节变化特征。得到的主要结论如下：（1）给出了东海水团的四季分布情况，并揭示其消长变化规律及其主要的影响因素。结果表明，在东海600m以浅海域，夏季主要存在陆架沿岸水、东海表层水、东海深层水、黑潮表层水、黑潮次表层水、黑潮中层水、黄海表层水和黄海底层水8个水团；而冬季，由于偏北风的增强和垂向混合的加强，黑潮次表层水、东海深层水和黄海底层水随之消失，只存在黑潮表层水、黑潮中层水、东海表层水、陆架沿岸水和黄海表层水5个水团。黑潮次表层水、东海深层水和黄海底层水是季节性水团，只存在于4月至9月间。陆架沿岸水、东海表层水和黑潮表层水的温度和盐度具有十分显著的季节变化特征。风是影响东海水团范围季节变化的最主要因素，它控制着闽浙沿岸流、台湾海峡流的强度，同时还控制着黑潮及其分支的入侵强度。总而言之，风、黑潮及其分支是影响东海主要水团变化的动力学因素，而海表热通量和淡水通量则是影响水团温盐特性变化的重要热力学因素。（2）系统地研究了台湾暖流水体积的季节变化特征，并阐述了其来源组成。结果表明，台湾暖流水是东海陆架海域最重要的水团，它的体积具有冬季最大（13746立方公里），秋季最小(11397立方公里)，夏季(13165立方公里)、春季（12553立方公里）次之的特点。在秋、冬季，台湾暖流水主要来源于台湾东北部黑潮水的入侵；而在春、夏季，台湾暖流水分为台湾暖流表层水和台湾暖流深层水，其表层水是由来自台湾海峡的暖流水和台湾东北部入侵的黑潮表层水混合而成的，而其深层水则来源于台湾东北部的黑潮次表层水。暖半年期间（4月9月），台湾海峡北上的暖流水是台湾暖流水的主要来源。在49月间，台湾海峡表层暖流水的输送量分别为0.62Sv、0.83Sv、1.05Sv、1.67Sv、1.27Sv和1.04Sv（1Sv=106m3/s）。显然，台湾海峡暖水对台湾暖流水的贡献在7月达到最大，为1.67Sv，占28N断面台湾暖流表层水的56.5%。（3）揭示了东海黑潮流量的年际和年代际变化特征。东海黑潮流量基本服从正态分布，主要集中在19-33Sv范围内，其多年平均值为24.30Sv；流量的季节变化主要表现为夏强（25.91Sv）秋弱（24.27Sv）。最大熵谱分析表明,东海黑潮年平均流量的主周期依次为5.3a、24.9a和3.6a。显然，黑潮流量不仅存在着3-5a的年际变化，而且还具有约25a的年代际变化。季平均和冬、夏季东海黑潮流量均有长期的线性增强趋势，在1956-2005年间它们分别增加了8.73Sv、9.86Sv和9.38Sv。相关与合成分析结果表明，黑潮源区和东海黑潮流域上空的经向风异常是黑潮流量年际变化的重要影响因素，而PDO则对黑潮流量的年代际变化有重要作用。（4）构架了比较完整的东海环流系统。利用模拟结果，分析了东海及邻近海域各主要水道的水量输运、热量输运和盐量输运的变化特征。结果表明：东海的水交换过程具有明显的季节变化特征。从流量的角度来看，台湾海峡、台湾‐西表岛之间水道和西表岛‐冲绳岛水道是海流流入东海的三个主要水道，而冲绳岛‐奄美大岛、吐噶喇海峡、大隅海峡、济州岛东部和济州海峡是流出东海的水道；它们的年平均流量分别为1.06Sv、20.49Sv、3.2Sv、-0.67Sv、-20.59Sv、-0.30Sv、-2.37Sv、-0.67Sv和-3.05Sv（向内为正）。对比发现，东海与相邻海域各主要水道的水量输运、热量输运和盐量输运均具有相似的季节变化趋势，其最大值往往都出现在夏季（7月或8月），最小值一般都出现在冬季（1月或2月）。通过对热量输运的分析，发现东海是一个热源（0.172PW，1PW=1015W），它在全球大气‐海洋系统热输运和平衡过程中起着不可忽视的作用。更多还原

【Abstract】 The main physical processes in the East China Sea (ECS) include the evolutions ofwater masses in the ECS, the seasonal variations of the Taiwan Warm Current Water(TWCW) and its sources, the evolution of Kuroshio Volume Transport (KVT) in theECS, as well as the water exchange in the East China Shelf Sea and its seasonalvariations. These processes control the oceanography factors and the transports ofmass and energy in the ECS. Hence, a systematic study of these processes hasimportant scientific significance. Based on numerous historical in-situ data andsimulation data, this paper studied the evolution mechanisms of these critical marineprocesses in the ECS. The seasonal distributions of water masses in the ECS werediscussed using cluster analysis method, and the dynamic and thermodynamicmechanisms that affected these seasonalvariations were also discussed in detail. Onthe basis of water masses analysis, combined with the model results, the seasonalvariations of the volumeof the TWCW and its sources were explored. Using data inrecent50years derived from the Japan Meteorological Agency, the inter-annual andinter-decadal variability characteristics of the KVT in the ECS were analyzed; theinfluences of the meridional wind and Pacific Decadal Oscillation (PDO) on theKuroshio volume transport were also discussed. The Regional Ocean ModelingSystem (ROMS) was used to simulate the circulation structure of the ECS. Themonthly variability characteristics of the water transport, heat transport and salinitytransport through the main sections around the ECS were also analyzed by using themodel results. The main results and conclusions are as follows:(1) The seasonal distributions of water masses in the ECS were obtained by wateranalysis, and the evolution mechanisms of water masses were also discussed. In theECS above a depth of600m, there are eight water masses in summer but only five inwinter. Among these water masses, the Kuroshio Surface Water (KSW), KuroshioIntermediate Water (KIW), ECS Surface Water (ECSSW), Continental Coastal Water(CCW), and Yellow Sea Surface Water (YSSW) exist throughout the year. The Kuroshio Subsurface Water (KSSW), ECS Deep Water (ECSDW) and Yellow SeaBottom Water (YSBW) are all seasonal water masses, occurring from April throughSeptember. The CCW, ECSSW and KSW all have significant seasonal variations,both in their horizontal and vertical extents and in their T-S properties. The wind is thedominant cause of the seasonal variation in spatial extent of the CCW, ECSSW andKSW. It determines the extent of the ZMCC, the strength of the Taiwan Strait Current,and the intrusion of the Kuroshio.In other words, the wind stress, the Kuroshio and itsbranch currents, and coastal currents are all the dynamical factors determining theseasonal variations in the spatial extent of the CCW, the ECSSW and the KSW. Seasurface heat and freshwater fluxes and river runoff might also be important factors inthe seasonal variations of T-S properties of the three water masses.(2) Theseasonal variations of the volumeof the TWCWas well as its origins wereanalyzed. The results indicated that the Taiwan Warm Current Water was dominatewater mass in the East Chia Shelf Sea; the volume of the TWCW exhibitedpronounced seasonal variations, it reach a maximum (13746km3) in winter, secondin summer (13165km3) and spring (12553km3), andminimum (11397km3)in autumn,,respectively. In winter and autumn, the TWCW is mainly coming from shelf intrusionof the Kuroshio northeast of Taiwan; however, in spring and summer, the TWCW canbe divided into two types: Taiwan Warm Current Surface Water (TWCSW) andTaiwan Warm Current Deep Water (TWCDW). The TWCSW is formed by the mixingof the Kuroshio Surface Water from the east of Taiwan with the water coming fromTaiwan Strait, and the TWCDW is completely originated from the KuroshioSubsurface Water East of Taiwan. In warm half year (April-September), the TWCSWcoming from Taiwan Strait are0.62,0.83,1.05,1.67,1.27and1.01Sv（1Sv=10）respectively. Obviously, the warm water from Taiwan Strait make largest contributionto the TWCSW in July (1.67Sv), about56.5%.(3) High inter-annual and inter-decadal variability was identified in the KuroshioVolume Transport. The analysis results showed thatthe frequency distributions ofKVT appeared nearly to obey normal distribution with a range of19-33Sv; themulti-year seasonal average of the KVT through the PN section is24.30Sv.The (25.91) in summer and minimum (24.27) in fall. The spectral analysis resultsindicated that the primary periods of the KVT variations were5.3,24.9and3.6a,respectively.A linear long-term KVT upward trend was identified for the period1956to2005, the seasonal mean, winter and summer volume transports increased8.72Sv、9.86and9.38Sv in this period, respectively. Correlation and composite analysisshowed that meridional wind anomalies over the source area of Kuroshio and theKuroshio area in the East China Sea were responsible for the inter-annual variabilityin the KVT. Additionally, the inter-decadal variability of the KVT was closelyassociated with the PDO.(4) The relatively complete system of the circulation structure in the ECS wasconstructed. The ROMS results were applied to analyze the monthly volume transport,heat transport and salinity transport through the critical sections in the ECS andadjacent regions. Analysis results showed that the water exchanges in the ECSexhibited pronounced seasonal variations, which mainly take place in the TaiwanStrait (TWS), the section east of Taiwan (TWE), the two sections along Ryuku Island(R1and R2), the Tokara Strait (TKRS), the Osumi Strait (OS), the section east ofCheju Island(CE) and Cheju Strait (CS). The annual mean volume transport throughthese sections were1.06Sv,20.49Sv,3.2Sv,-0.67Sv,-20.59Sv,-0.30Sv,-2.37Svand-0.67Sv (Positive means inward). Comparison of these transports (volume, heatand salinity) indicated that these transports in the ECS had similar trends, themaximum flux often appeared in summer (July or August), and the minimum oftenappeared in winter (January or February). The results also showed that the ECS was aheat source (0.172PW,1PW=1015W), it played a critical role in theglobalheatbalances and transports in the atmosphere and ocean.更多还原