黄海夏季温度分布及相关现象的数值研究

IOCAS-IR > 海洋环流与波动重点实验室

	黄海夏季温度分布及相关现象的数值研究
	刘克修
学位类型	博士
	1998
学位授予单位	中国科学院海洋研究所
学位授予地点	中国科学院海洋研究所
学位专业	物理海洋学
摘要	本论文应用数值方法, 对夏季黄海的温度分布状况及其相关的现象,如黄海冷水团、潮汐锋、温跃层以及溶解氧垂直分布最大值等进行了研究.第二章，用一个二维断面模式，模拟增温期（从4月到8月）黄海潮汐锋的形成和演化过程，对南黄海和北黄海的5条主要断面进行了后报试验。将表层和底层温度、跃层深度、潮汐锋位置等的后报结果与实测结果相比较可以看出：结果是令人满意的。就温度随断面分布及层化现象随时间的变化趋势来看，计算与实测表现出较好的一致性。各断面表、底层温度平均预报合格率及潮汐锋位置预报总成功率都很高。说明本模式是成功的，可以用于黄海潮水汐锋的数值预报.溶解氧不但是海洋调查的主要内容之一也是一个非常重要的水文要素。我国许多学者对黄海溶解氧垂直分布最大值进行了研究，指出夏季黄海溶解氧的分布状况主要由水温控制，溶解氧的分布与水温分布密切相关，但我国在此方面的数值研究工作尚属空白。在第二章工作基础上，第三章建立了一个二维断面溶解氧的数值模式，模拟了夏季黄海溶解氧垂直分布最大值的形成和演化过程，并对影响溶解氧生垂直分布状况的三种主要过程：即垂直涡动混合、生物活动和海气界面的气体交换进行了数值试验和讨论。结果表明，在增温期，由于温跃层的形成和存在，限制了垂直方向的交换，使跃层下界附近的溶解氧得以保留，同时上层海气交换和下层有机物分解耗氧，从而在跃层附近形成最大值；由于黄海海区的跃层一般都在真光层以内因此浮沲植物的光合作用产氧可以增加跃层附近氧的含量，进而影响最大值的大小但对是否开成最大值影响不大；上混合层中的生物产氧大都通过海气界面的气体交换进入大气。海气界面的气体交换速度可以影响上混合层的溶解氧浓度，但对溶解氧最大值影响很小。夏季黄海的温度分布明显具有三维特征，在前面二维数值工作的基础上，第四章又进一步作了三维数值研究。在诸多三维数值模式中，普林斯顿海洋模式（POM）在国外应用最为广泛。第四章首先简单介绍了POM模式，然后模拟了黄海的潮汐和潮流，给出了潮汐和潮海的一些主要特征，包括无潮点、等振幅线和同潮时线、潮流分布等。最后将POM模式应用于黄海，以黄海温度的垂直均匀分布（4月）状态为初值，考虑海面热交换、风应力和潮的作用，对黄海的温度结构进行了数值模拟，基本上再现了黄海冷水团、潮汐锋和温跃层的形成和演化过程。模拟结果显示：由于太阳辐射，原本垂直混合均匀的海水开始层化：由于风的涡动混合作用，上层海水混合均匀，形成上混合层：下层海水则由于潮水的混合作用而混合均匀。这样，在深水区形成了温跃层；在浅区和深海区之间等温线密集，从而形成了温度锋。在整个增温期，底层冷水得以保存，温跃层则不断增强.
其他摘要	This dissertation focus on the distribution of the temperature in the Yellow Sea, the phenomenon related to temperature, such as the Yellow Sea Cold Water Mass, the tidal front, the thermocline and the maximum of vertical distribution of dissolved oxygen are investigated with numerical methods. In chapter 2, the formation and evolution of the sectional temperature distribution, thermal front and thermocline in the Yellow Sea during the April to August warming period are simulated with a two-dimensional model. Numerical hindcast experiments are made in five main sections of the Yellow Sea. The hindcast temperature at surface and bottom layers, the thermocline depth and the position of the thermal front at the bottom agree well with measured data. The distribution of temperature and the evolution of stratification are well reproduced by the model. The stations with hindcasted temperature error less than 2 ℃ and 1.5 ℃ make up 84% and 72% of the total respectively, and the positions of tidal front with hindcasted error less than 45Km make 92% of the total. It is shown that the simulation taken with the model is successful and the model may be used to prognostic the thermal front and sectional distribution of temperature of the Yellow Sea. Dissolved oxygen in sea water is not only one of the essential factors of oceanographic survey, but also one of the most important and fundamental parameters of marine chemistry, physical oceanography and marine biology. Many Chinese researchers have discussed the distribution and variation of dissolved oxygen in the Yellow Sea. It was pointed out that the distribution and variation of dissolved oxygen is mainly regulated by sea water temperature. But no numerical work has been done yet. In chapter 3, a two-dimensional model is established to study the temporal evolution of the maximum of vertical distribution of dissolved oxygen in the Yellow Sea. Three major processes which regulate the variations of dissolved oxygen, i.e., vertical mixing, biological activity of marine organisms and gas exchange at the air-sea interface, are discussed. It is shown that the major mechanisms of forming and retaining the maximum of dissolved oxygen are the weakened vertical mixing near the bottom of the thermocline, the gas exchange at the air-sea interface and the consumption of oxygen due to the oxidation of organic matter under euphotic layer and at the bottom during the warming periods. Since the thermocline lies in the euphotic zone in the Yellow Sea area, the biological production contributes to the maximum but does not determine the maximum's formation or retention. Most of the biological production in the upper mixing layer get into the air by gas exchange in the air-sea interface. The transfer velocity of gas exchange can affect the concentration of dissolved oxygen in the upper mixing layer, but has very little influence on the maximum. In summer, the temperature and currents in the Yellow Sea have a clear significant three-dimensional structure. The three-dimensional baroclinic study is carried out in chapter 4. The general theory of Princeton Ocean Model(POM) is presented in this part firstly. The main characteristics of the tides and tidal currents in the Yellow Sea are well reproduced with POM. These include the tidal amphidromic point, co-tidal charts, and distribution of tidal currents et ac. Then the distribution and evolution of the temperature in the Yellow Sea in summer are simulated with POM. As the initial condition, the temperature is vertical uniform in April. The solar radiation, wind stress and tidal effects are considered in the model. The formation and evolution of the Yellow Sea Cold Water Mass, tidal front and thermocline are well reproduced by the model. The well-mixed water is stratified due to solar radiation. Then the upper mixing layer is formed due to the wind stress, also the bottom layer is well mixed due to the tidal effect. So, the thermocline is formed in deep sea region, the water is well mixed in the shallow sea region, and the tidal front is formed between the two regions. The cold water in the bottom is retained during the whole warming period, and the thermocline becomes stronger.
页数	121
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/1397
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	刘克修. 黄海夏季温度分布及相关现象的数值研究[D]. 中国科学院海洋研究所. 中国科学院海洋研究所,1998.

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