南海北部湾FVCOM潮汐模式的高度计同化模拟研究

发布时间：2018-01-08 07:34

本文关键词：南海北部湾FVCOM潮汐模式的高度计同化模拟研究　出处：《上海海洋大学》2014年硕士论文　论文类型：学位论文

更多相关文章： FVCOM 北部湾 高度计 潮汐 分布式摩擦

【摘要】：潮汐水动力对于近海渔业捕捞和海洋生态研究非常重要。本文基于非结构网格有限体积FVCOM模式建立北部湾潮汐模式，并利用近6.5年Jason-1卫星高度计沿轨数据提取的潮汐信息对模式使用Nudging方法进行同化。模式将OTIS（OSU Tidal Data Inversion）里China Sea范围中六个分潮（S2，M2，N2，K1，O1，Q1）的调和常数的水位预报值作为开边界驱动。本文主要采用三个方案建立北部湾潮汐模式，1)仅采用开边界进行驱动，底摩擦系数采用常值0.0015。2)在方案1的基础上，加入高度计数据进行同化。3)在方案1的基础上，优化边界条件并采用分布式摩擦。由方案2和方案1的结果比较得出，高度计数据同化在计算区域内对模式精度有所改进， m1[(K1+O1)/2]振幅的平均绝对误差由24.73cm减小到5.91cm，迟角平均绝对误差由14.76°减小至11.11°。M2振幅的平均绝对误差由7.96cm减小到7.57cm，迟角平均绝对误差由34.33°减小至7.21°。改进效果比较明显。但是与验潮站数据相比，达不到理想的精度。由方案3和方案1的结果比较得出，底摩擦对模式精度亦有所改进。m1振幅的平均绝对误差由24.73cm减小到2.74cm，迟角平均绝对误差由14.76°减小至5.40°。M2振幅的平均绝对误差由7.96cm减小到6.19cm，迟角平均绝对误差由34.33°减小至7.24°。与方案二相比，方案三的结果与实测数据更为接近，可以更明显的模拟出潮汐场形态的局部特征。可能是由于北部湾是浅水湾地区，Jason-1在本区域内的测量精度存在疑问，另外计算区域内地形复杂，岛屿较多，岛屿附近测高点数据不连续，也会影响高度计的测量精度。研究区域较小，卫星轨迹间隔较大，，卫星数据空间分辨率较低。高度计资料采样的时间间隔较大，容易引起潮汐的高频混淆。本文详细分析了m1和M2分潮的潮汐和潮流特征。方案2和3模式结果与以往研究者的结果基本一致。模式结果表明：北部湾海域表现为标准的全日潮性质， m1在计算区域的西南部振幅偏小，在越南顺化沿岸有一个退化了的无潮点，同潮时线沿着此点做逆时针旋转。M2分潮在北部湾的振幅与m1相比普遍较小，M2分潮在海防北部有一个退化无潮点，同潮时线沿着此点逆时针传播。北部湾潮流和潮汐一样，m1分潮为主要分潮。海南岛西岸及西北岸m1分潮的潮流速度比M2分潮大的多。m1和M2分潮的长轴走向除了在琼州海峡是东西方向，其余都与北部湾的湾轴方向基本一致。对于m1和M2分潮来说，北部湾大部分海区潮流是往复流，但在琼州海峡西侧表现出很强的旋转型。除此之外琼州海峡东侧m1和M2分潮也表现出比较强的旋转性。m1分潮在海南岛南侧北部湾湾口，还有M2分潮在海南岛西侧北部湾内也有较强的旋转性。
[Abstract]:Tidal hydrodynamics is very important for the study of offshore fishing and marine ecology. In this paper, the Beibu Gulf tidal model is established based on the unstructured grid finite volume FVCOM model. The model is assimilated by Nudging method using tidal information extracted from Jason-1 altimeter data in the past 6.5 years. In the model, the six tidal components in the China Sea range of OTIS(OSU Tidal Data inversion are S2M2N2N2K1O1. In this paper, three schemes are used to establish the Beibu Gulf tidal model. The coefficient of bottom friction is constant 0.0015.2) on the basis of scheme 1, the altimeter data is added to assimilate. 3) on the basis of scheme 1, the boundary conditions are optimized and distributed friction is adopted. By comparing the results of scheme 2 and scheme 1, it is concluded that the data assimilation of altimeter improves the accuracy of the model in the calculation area, and M1. [The mean absolute error of the amplitude of K _ (1) O _ (1 / 2) decreased from 24.73 cm to 5.91 cm. The mean absolute error of the amplitude of delay angle decreased from 14.76 掳to 11.11 掳路M2 from 7.96 cm to 7.57 cm. The average absolute error of the delay angle is reduced from 34.33 掳to 7.21 掳. The improved results are obvious, but compared with the tide station data, the accuracy is not satisfactory. By comparing the results of scheme 3 and scheme 1, it is found that the average absolute error of the amplitude of the bottom friction pair is reduced from 24.73 cm to 2.74 cm. The mean absolute error of the amplitude of delay angle decreased from 14.76 掳to 5.40 掳路M2 from 7.96 cm to 6.19 cm. The mean absolute error of late angle is reduced from 34.33 掳to 7.24 掳. Compared with scheme 2, the result of scheme 3 is closer to the measured data, and the local characteristics of tidal field can be simulated more obviously. It is possible that the accuracy of Jason-1 measurement in the Beibu Gulf is in doubt in the repulse Bay area. In addition, the topography of the calculation area is complex, there are more islands, and the height data near the islands are not continuous. The measurement accuracy of altimeter is also affected. The study area is smaller, the satellite trajectory is larger, the spatial resolution of satellite data is lower, and the time interval of altimeter data sampling is larger, which is liable to cause the high frequency confusion of tide. In this paper, the tidal and tidal current characteristics of M1 and M2 tides are analyzed in detail. The results of models 2 and 3 are in good agreement with those of previous researchers. The results of the models show that:. The sea area of Beibu Gulf is characterized by a standard diurnal tide. The amplitude of M1 is small in the southwestern part of the calculated area, and there is a degenerated non-tidal point along the hue of Vietnam. The amplitude of the m 2 component in Beibu Gulf is generally smaller than that of M 1 along the counter clockwise rotation along the same tide time line. There is a degenerated non tide point in the northern coast of Haiphong. The isotide line propagates counterclockwise along this point. The Beibu Gulf tidal current is the same as the tide. M 1 is the main component. The velocity of m 1 in the west coast and the west west coast of Hainan island is much higher than that in m 2. The long axis of m 1 and m 2 is more than that of m 2, except in the Qiongzhou strait. The rest are basically consistent with the Bay axis of the Beibu Gulf. For M1 and M2 tides, the tidal currents in most of the Beibu Gulf are reciprocating currents. In addition to the east side of Qiongzhou Strait M1 and M2 tide also show a strong rotation. M1 tide in the southern side of Hainan Island Beibu Gulf mouth. And the M 2 tide also has strong rotation in the Beibu Gulf on the west side of Hainan Island.
【学位授予单位】：上海海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P731.23;P714.1

【参考文献】