【作者】 宋军；

【导师】 鲍献文； 薛惠洁；

【作者基本信息】 中国海洋大学 ， 物理海洋学， 2010， 博士

【摘要】 基于嵌套的海洋环流数值模型,分别对东中国海陆架海区与近岸局部海区的两个具有代表性的水交换问题进行了探讨。对于每个水交换问题的具体需要,选取了不同网格构造方式但紧密耦合的数值模型,并结合相应的观测资料首先对所在海区影响水交换的主要物理背景因素进行了分析。针对这两个互为补充的水交换问题,分别构建和使用了相应的研究方法。其互补性表现为：前者是在给定的水交换强度下,对水交换区域的面积和位置的时空分布规律进行了研究；后者是在研究区域给定的情况下,研究了该区域与外海水的水交换强度情况。利用三维的海洋环流数值模型ROMS (Regional Ocean model System)对东中国海海域的黑潮流系系统(东中国海黑潮流系)的季节变化与年际变化进行了模拟和研究。数值模型积分时间自1991年到2008年。东海黑潮流系的变化规律被自西向东划分为三段分别进行了讨论。本论文给出了东海黑潮流系穿越东海大陆架200米等深线的体积通量以及其变化规律,并使用最新的经过质量验证的31个剖面Argo浮标轨迹对此体积通量结果的年平均状态进行了验证。从月平均结果上来看,此向岸的体积通量于夏季减到最小,为0.4796 Sv(1 Sv≡106m3 s-1)；于冬季达到最大值,为1.69 Sv。通过对长时间模型模拟结果的时间序列分析,本文揭示了黑潮于台湾岛东部的通量的季节变化幅度,在2000年之后相对于2000年之前呈现出变化减弱的现象。谱聚类方法被引入到海洋科学研究,并以此为基础初步构造了一个研究水交换与混合的新的研究方法：谱混合模型(Spectral Mixture Model)。本研究使用谱混合模型定义了东海黑潮流系与东中国海大陆架水的交换区,并研究了其变化规律。该交换区的变化与上述东海黑潮流系穿越东中国海大陆架200米等深线的向岸体积通量的变化呈现出-0.78的显著的负相关关系。研究结果同时指出来自太平洋的季节内信号有可能穿越黑潮主轴进入东中国海海域。基于对2006年夏季与2007年冬季在123.51°E,38°N位置一个月海流和水位观测数据的分析,发现夏季余流呈现两层结构,上层流向为西北,下层流向东南,并且在大潮日期附近,在跃层附近深度存在若干流速较强的水层；冬季余流除了个别层以外基本上均为西北向流入北黄海,从中可以看到风场改变所引发的异常增减水和强流出现。对潮流椭圆的分析表明,半日潮族分潮流的最大流向自夏季至冬季存在着顺时针的旋转,旋转角大约为16～18°,并且夏季半日潮族随深度顺时针,全日潮族随深度逆时针旋转,而冬季基本上由表层到底层上下一致。长海县位于黄海北部海域,辖五个乡镇,经济皆以水产为主,海域营养物质的交换能力对其增养殖潜力影响较大,其中海域的营养物质可以用颗粒有机物(POM)和溶解有机物(DOM)表征。应用国际先进的无结构有限体积法的海洋模型FVCOM (An Unstructured Grid, Finite-Volume Coastal Ocean Model),基于四个连续测流站、三个水位计以及此海域中一个ADCP的观测资料,分不同季节共二十种情况对此海域及其五个乡镇表征营养物质的颗粒有机物和溶解有机物的交换能力分别进行了计算,分析了各种因素在此交换过程中所占的比重,并给出了所研究海域水滞留时间的空间与时间分布规律。本文研究成果的科学意义主要表现为：构建了用于解决水交换以及水团分析问题的谱混合模型方法的框架；基于动力学关系给出了两个水交换问题的一般研究方法；完善了东中国海物理环境演变理论体系。更多还原

【Abstract】 Based on the nested ocean numerical model, two classic questions of water exchanges, which are from the shelf sea area and a local sea area of East China Sea (ECS), are discussed in this paper.For satisfying the specific needs of each water exchange question, different ocean circulation models by holding defferent style of mesh structure but similar forced boundary condition are used for each question. Combined with the result of the ocean models and relevant in-situ data, the major factors of influencing water exchanges are firstly analysed.To study these two complementary questions, we construct or apply two appropriate methods for approaching the truth.The complementarity shows like this:One is studying the spatial-temporal distribution regularities of the water exchange zone which is based on the specific strength of water exchange and mixing;Another is calculating and analyzing the water exchange strength between the sea area and its adjacent water,and this sea area is specified.The variability of the Kuroshio in the East China Sea during the period of 1991 to 2008 is studied using a three-dimensional circulation model. The model calculated Kuroshio onshore volume transport in the East China Sea reaches the minimum of 0.48 Sv (1 Sv=106 m3 s-1) in summer and the maximum of 1.69 Sv in winter. Furthermore, the model result indicates that the Kuroshio transport east of Taiwan decreased since 2000. Lateral movements tend to be stronger for both ends of the Kuroshio in the East China Sea compared to the mid segment. The Spectral Mixture Model (SMM) is adapted to determine the exchange zone between the Kuroshio and the shelf water of the East China Sea in this study. There is a significantly negative correlation,-0.78, between the area of the exchange zone and the Kuroshio onshore transport across the 200 meters isobath in the East China Sea. In addition to the annual and semi-annual signals, the intra-seasonal signal likely of the Pacific origin may also induce Kuroshio intrusions and exchange events in the East China Sea.Analysis of tidal current and sea level has made based on the observations during summer in 2006 and winter in 2007, respectively. The result indicates that a two-layer structure of residual current exists in summer, with its upper layer northwestward and lower layer reversed. In addition, some strong residual occurs nearby the pycnocline during astronomical tide; In winter, the entire residual directed to northwestward, with abnormal sea-level fluctuation and associated current. Analysis of tidal ellipse indicates that in summer the semi-diurnal component rotates clockwisely with depth while for diurnal component counterclockwisely. But in winter the vertical structure is almost homogeneous. Moreover, a clockwise rotation exists for the direction of semi-diurnal component from summer to winter,with a angle of 16～18°.County ChangHai is located in North Yellow Sea.It contains five villages and towns. Breed aquatics is the main economy in all of these five villages. Breed aquatics rely heavily on the exchange of nutriment.The nutriment can be denoted by POM(Particulate Organic Matter) and DOM(Dissolved Organic Matter) here.By making use of FVCOM(An Unstructured Grid, Finite-Volume Coastal Ocean Model) and being based on the consecutively observed data from three waterlevel instruments and one ADCP in this sea area, POM and DOM in all these five villages are calculated in twenty conditions.The proportions of different factors in the exchange are given.And the spatial and temporal distribution regularities of water residual time in the ChangHai sea area is estimated.The scientific significances of this study are:Construct the theory frame of the Spectral Mixture Model which is for water exchange studies and water mass analysis; demonstrate two general water exchange models under the basic dynamics; perfect the physical environmental evolution theory system of the East China Sea.更多还原