【作者】 杜凌；

【导师】 左军成；

【作者基本信息】 中国海洋大学 ， 物理海洋， 2005， 博士

【摘要】 从285个长期验潮站的分析结果看,海平面的长期变化趋势的变化幅度很大,就总体量级而言,基本上处于±2mm/a的量级,但某些站会出现极端值,如最大在马尼拉可达16.34mm/a。由于受地壳变化的影响,单站分析结果极不均衡,空间跳跃性很大。285个长期验潮站所得到的平均线性变化速率为1.69mm/a。 根据对T/P高度计资料的分析,绘出的线性变化速率的等值线分布图说明,全球海平面变化趋势在空间上的分布也不均衡,表现出显著的区域特征,但不像验潮站的分析结果跳跃性那么大。全球的极值区出现在西太平洋赤道区域,以及西北太平洋（40°N,145°E）附近一个很窄的带内,其核心区值可达30mm/a。东太平洋为下降区,核心值可达-20mm/a。印度洋的西北海区为显著的下降区,其核心区值达-10mm/a。大西洋的变化比较平缓,基本在-2mm/a～5mm/a之间。就全球平均状况而言,海平面的上升速率为2.2mm/a。 热膨胀是T/P高度计观测到的大尺度平均海平面季节变化的主要贡献者,尤其对带状区域和洋盆尺度的平均状况,北半球约为季节变化的80—90%。 某些区域T/P结果与比容变化存在较大的不一致,尤其在南半球,这主要是因为温度观测数据稀少。另一个重要的因素是T/P资料较短,而比容估计则使用了很长的历史资料。两资料都表明,北半球比南半球有更强的季节信号,而南半球要弱得多。 T/P观测和比容模型得到的全球MSL变化的位相差是一系统偏差。除了前面提到的误差来源,还受如海洋、大气、陆地的水循环的水量重新分布对T/P观测的全球MSL变化的显著影响,而这在比容变化中无法考虑。 本文采用三维斜压陆架浅海POM模式模拟了渤黄东海的潮汐潮流特征,得到与实测符合较好的结果。为了提高台湾海峡潮波的模拟精度,特选择有限元模型,以更好地拟合边界。本文基于POM模型的结论和其他学者的相关结果,构造台湾海峡两侧开边界,应用三维浅海有限元QUODDY模式,较准确地模拟了台湾海峡的潮波特征。 渤、黄、东海的潮波模拟采用POM模型,水平网格是5′×5′。与159个测站的4个主要分潮平均绝对偏差分别为:M₂分潮的振幅和迟角分别为1.69cm和5.03°,S₂为3.52cm和13.78°;K₁为1.95cm和4.69°,O₁为8.18cm和8.34°。与15个观测点的实测的M₂分潮流的东分量、北分量的调和常数的平均绝对偏差别为:7.4cm/s,12.8°和7.7cm/s,11.3°;K₁的东、北分量的调和常数的平均绝对偏差为3.3cm/s,26.0°和3.7cm/s,更多还原

【Abstract】 According to the stochastic dynamic analysis results of 285 tide gauge data, long term sea level trend has a substantial spatial range, generally sea level rise has the order of ± 2mm/a, but it is changing strongly from station to station, with the 16.34mm/a maximum in Manila, whose irregular distribution is probably mainly caused by crust vertical movement. The average rising rate of the total 285 tide gauge station is 1.69mm/a.The spatial distribution of sea level variation trend resulted from T/P altimetry data shows substantial inhomogeneity, with strong regional characteristics, but there is not so strong jump in space as the result from tide gauge data. The maximum region of sea level trend appears in the west tropical Pacific, with the maximal value of about 30mm/a in the core. East Pacific is in the region of decreasing substantially, with the miminum of -20mm/a in the core. It is falling in the northwest Indian Ocean with the core value of -10mm/a. Compared with other regions it is very smooth in the Atlantic Ocean with the value of -2mm/a~5mm/a. The sea level is rising at the rate of about 2.2mm/a in global mean.Thermal expansion is responsible for much of the large-scale seasonal variations observed by TOPEX/Poseidon altimeter, especially in averaging over zonal regions and basin scales, it can count for about 80~90% of the seasonal variability in the northern hemisphere.Large discrepancies, especially in the southern hemisphere, are mainly due to the sparse temperature measurement. Another possible reason is that the TOPEX/Poseidon results are averaged over a short period, for example 10 years only, and the steric estimates are primarily based on climatological data averaged over a much longer period. The sea level height changes obtained from TOPEX/Poseidon measurement and steric estimate indicate considerably stronger seasonal signals in the northern hemisphere than in the southern hemisphere.The phase difference in global MSL variations between TOPEX/Poseidon observation and steric model prediction implies a systematic difference between them. Besides the error sources mentioned above, it may come from a variety of others, for example, the water massredistribution between the oceans, atmosphere, and continental water cycle may play significant roles on TOPEX/Poseidon observed global MSL change, which are not included in the steric estimate.The three-dimensional baroclinic model POM is used to simulate the characteristics of tide and tidal waves of Bohai Sea, Yellow Sea and East China Sea.. The horizontal grade of this model is 5’X5’. Compared with the tide gauge data of 159 stations in this region, the mean absolute deviations of amplitude and phrase of M2, S2, K|, Oj are (1.69cm, 5.03°), (3.52cm, 13.78°), (1.95cm, 4.69°) and (8.18cm, 8.34°) respectively, and with the observation of tidal current in 15 stations in this region, the mean absolute deviations of the harmonic constants of the eastward and northward components of M2 are (7.4cm/s, 12.8°)and(7.7cm/s, 11.3°); those of Ki are (3.3cm/s, 26.0°) and (3.7cm/s, 31.3°).To improve the simulation of tidal wave in Taiwan Strait, the Finite Element Model (FEM) of QUODDY is appliedwith a more realistic boundary, which the north open boundary condition is provided with the results of POM in the East China Sea. Based on the numerical simulation results, the characteristics of tide and tidal currents in Taiwan Strait are analysed. Compared with the tide gauge data of 37 stations in the area, the mean absolute deviations of amplitude and phrase of M2, S2, K,, Oi are(7.35cm, 9.01°), (5.77cm, 21.52°), (3.69cm, 8.28°) and (3.58cm, 5.33°) respectively, and with the analysis result of tidal current in 5 current observation stations in the study region, the mean absolute deviations of the harmonic constants of the eastern and northern components of M2 are (lO.lcm/s, 29.8° )and(12.2cm/s, 30.2° ),and those of Ki are(5.3cm/s, 47.7° ) and (5.7cm/s, 49.8° ).Great controversy remained in the previous numerical modeling about the cotidal distribution of the maximum tidal current of M2 constituent. This paper confirms that there is an area with dense cotidal lines of M2 constituent and the northward wave of M2 constituent is more important than the southward one.For the study of the effect of the long term sea level variation on the tidal wave within East China Sea, numerical simulation experiment is made on the tidal wave in the studying area, provided a sea level rise of 60cm. It is concluded that mean sea level variation affects tidal waves markedly in the East China Sea, such effect includes the variations of both the amplitude and the tidal wave propagation. The Numerical simulation result and the harmonicanalysis result of tide gauge data agree very well and validate the above conclusion. Generally speaking, the tidal amplitude varies in the same phase with mean sea level variation, but it decreases with rising mean sea level in some regions. For example the area north of Yangtze River estuary is a typical region where tidal amplitude decreases as mean sea level rises. The maximal variation area is along Fujian and Zhejiang coast, the amplitude of M2 increases by about 12cm with a sea level rise of 60cm. The north coast of Jiangsu, the south east coast of Shandong, and the south east coast of Liaoning are the other areas influenced dramatically.Generally, the phase-lag decreases as mean sea level rises, but the variation range is small. The areas where the tidal phase-lag increases with rising mean sea level are all very limited and near corresponding amphidromic points. The spatial distribution of such variation is slightly different between diurnal tides and semi-diurnal tides.更多还原