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101.
涨落潮槽是河口区的重要地貌单元。只有枯季涨潮槽才能表现出涨潮优势。使用ADCP和ENDECO在枯季对长江口典型涨落潮槽进行一个潮周期的同步水文观测。利用本次观测资料和收集以前洪季水动力结果,比较分析了长江口涨落潮槽一个完整洪枯季大小潮水动力特征和输运机制。结果表明:(1)长江河口涨潮槽的水动力极为复杂。不仅存在洪枯季节的水文特征变化,而且存在着洪季大小潮和枯季大小潮的变化;(2)只有枯季大潮表现出较为明显的涨潮优势。涨潮槽的单宽涨落潮量接近,而落潮槽的单宽涨潮量都小于单宽落潮量;(3)洪季大小潮涨潮槽的平均涨潮流速都大于落潮槽,平均落潮流速都小于落潮槽。枯季小潮的平均涨潮流速来说,涨潮槽大于落潮槽;而对于落潮流速来说,涨潮槽上部小于落潮槽,下部大于落潮槽;(4)涨潮槽的欧拉余流要小于落潮槽,涨潮动力减弱对涨潮槽的影响较为明显。 相似文献
102.
103.
The results of the new concept of coastal sea circulation are demonstrated by numerical simulations for the first time. The numerical experiments in three types of rectangular model seas illustrate the dependence of circulation on tidal phases due to the convectively nonlinear effect which is estimated by a newly defined drift dispersion in-dex. Then, the present theory is applied in the Bohai Sea of China. At the Bohai Straits and the Huanghe River mouth area the circulation direction even reverses owing to different initial tidal phases which shows that the the-ory copes with nonlinearity well. The calculated M2 tide-induced residual circulation shows that a clockwise gyre exists in the center of an anticlockwise gyre in the central Bohai Sea due to the topographic features. In the Bo-hai Gulf the tide induced circulation shows a 3D structure with outflow at the surface and the inflow at the bottom which can partly explains the spread of the Huanghe River fresh water out of the Bohai Gulf and the inflow of the sediment from the Huanghe River. 相似文献
104.
GPS精密星历的轨道内插方法比较 总被引:3,自引:1,他引:2
在高精度的GPS测量数据处理过程中,获取高精度卫星轨道是重要的环节,内插是获取任意历元的精密轨道信息的重要手段,对拉格朗日插值法、牛顿插值法、Neville逐次线性内插法和切比雪夫插值法的效果做了细致的比较,并在此基础上进一步探讨了短时间外推的效果。 相似文献
105.
TOPEX/POSEIDON altimeter data from October 1992 to June 2002 are used to calculate the global barotropic M2 tidal currents using long-term tidal harmonic analysis. The tides calculated agree well with ADCP data obtained from the South China Sea (SCS). The maximum tide velocities along the semi-major axis and semi-minor axis can be computed from the tidal ellipse. The global distribution of M2 internal tide vertical energy flux from the sea bottom is calculated based on a linear internal wave generation model. The global vertical energy flux of M2 internal tide is 0.96 TW, with 0.36 TW in the Pacific, 0.31 TW in the Atlantic and 0.29 TW in the Indian Ocean, obtained in this study. The total horizontal energy flux of M2 internal tide radiating into the open ocean from the lateral boundaries is 0.13 TW, with 0.06 TW in the Pacific, 0.04TW in the Atlantic, and 0.03 TW in the Indian Ocean. The result shows that the principal lunar semi-diurnal tide M2 provides enough energy to maintain the large-scale thermohaline circulation of the ocean. 相似文献
106.
A Lagrangian tracer model is set up for Hangzhou Bay based on Coupled Hydrodynamical Ecological model for Regional Shelf Sea
(COHERENS). The study area is divided into eight subdomains to identify the dominant physical processes, and the studied periods
are March (the dry season) and July (the wet season). The model performance has been first verified by sea-surface elevation
and tidal current observations at several stations. Eight tracer experiments are designed and Lagrangian particle tracking
is simulated to examine the impact of physical processes (tide, wind and river runoff) on the transport of passive tracer
released within the surface layer. Numerical simulations and analysis indicate that: (1) wind does not change the tracer distribution
after 30 days except for those released from the south area of the bay during the wet season; (2) the tide and the Qiantang
River runoff are important for particle transport in the head area of the bay; (3) the Changjiang River runoff affects the
tracer transport at the mouth of the bay, and its impact is smaller in the dry season than in the wet season.
Supported by the Natural Science Foundation of China (No.40576080); National High Technology Research and Development Program
of China (863 Program, No. 2007AA12Z182) 相似文献
107.
黄海在有无潮作用下对“布拉万”不同响应的数值模拟研究 总被引:2,自引:0,他引:2
黄海是典型的强潮驱动的陆架浅海。为了研究黄海对台风的响应特点,本文利用区域海洋模式(Regional Ocean Modeling Systems,ROMS)分别模拟了在有潮和无潮作用下黄海对台风"布拉万"的响应过程。结果表明,不管潮存在与否,"布拉万"经过黄海后都引起了海表面降温和流速的近惯性振荡响应,这种响应主要分布于黄海中部较深区域,带通滤波提取的近惯性流速具有垂向第一模态特征。同时,研究发现强背景潮流能显著地影响黄海对"布拉万"的响应过程。主要结论如下:一方面,由于潮的存在,近岸垂向混合均匀的较暖水体与远岸较冷水体之间会形成潮混合温度锋面,"布拉万"过后,暖水发生了明显的离岸扩张,尽管路径右侧的混合层降温更显著,但是左侧即黄海西岸的暖水扩张更明显;另一方面,潮的存在减弱了布拉万产生的近惯性振荡响应,半日潮流在黄海仍然占据主导地位。在混合层中潮流的作用减弱了"布拉万"产生的近惯性能量,但也使其更易穿过跃层传入黄海内部。 相似文献
108.
Aureococcus anophagefferens, a small pelagophyte algae, has caused brown tide blooms in coastal waters of Qinhuangdao in recent years, presenting significant negative impacts on the shellfish mariculture industry. Under standard light microscopy, it is visually indistinguishable from other small algae in field samples due to its extremely small size. In this study, quantitative polymerase chain reaction(q PCR) based on 18 S r DNA sequences was developed and used to detect and enumerate A. anophagefferens. A linear regression(R2 = 0.91) was generated based on cycle thresholds value(Ct) versus known concentrations of A. anophagefferens. Twenty-two field samples collected in coastal waters of Qinhuangdao were subjected to DNA extraction and then analyzed using q PCR. Results showed that A. anophagefferens had a wide distribution in coastal waters along Qinhuangdao. Elevated A. anophagefferens abundance, category 3 brown tide blooms(200 000 cells/m L) occurred at Dongshan Beach and Tiger-stone Beach in August in 2013. In shellfish mariculture areas along coastal waters of Qinhuangdao, 4 stations had category 3 blooms, and 6 stations had category 2 blooms(35 000–200 000 cells/m L) in August and all stations had category 1 blooms(0 to ≤35 000 cells/m L) in October. Quantitative PCR allows for detection of A. anophagefferens cells at low levels in filed samples, which is essential to effective management and prediction of brown tide blooms. 相似文献
109.
2008年中国沿岸冬季寒潮激发陆架波的小波分析 总被引:1,自引:0,他引:1
This study applies the wavelet analysis to the tidal gauge records, alongshore winds, atmospheric temperature and pressure along the China coast in winter 2008. The analysis results show three events of sea level oscillations(SLOs) on the shelf induced by winter storms. The first event occurred from January 9 to 21. The SLO periods were double-peaked at 1.6–5.3 and 7.0–16.0 d with the power densities of 0.04–0.05 and 0.10–0.15 m2·d, respectively.The second event occurred from February 5 to 18. The SLO period was single-peaked at 2.3–3.5 d with power density of 0.03–0.04 m2·d. The third event occurred from February 20 to March 8. The SLO periods were doublepeaked at 1.5–4.3 and 6.1–8.2 d with the power densities of 0.08–0.11 and 0.02–0.08 m2·d, respectively. The SLOs propagated along the coast from Zhejiang in north to Guangdong in south. The phase speeds ranged about 9–29m/s from Kanmen to Pingtan, 5–11 m/s from Xiamen to Huizhou and 11–22 m/s from Huizhou to Shuidong. The dispersion relation of the SLOs shows their nature of coastal-trapped wave. 相似文献
110.
A three-dimensional isopycnic-coordinate internal tidal model is employed to investigate the generation,propagation, vertical structure and energy conversion of M2 internal tides in the Luzon Strait(LS) with mooring observations. Simulated results, especially the tidal current amplitudes, agree well with observations,demonstrating the reasonability and accuracy of the model. Results indicate that M2 internal tides mainly propagate into three directions horizontally, i.e., eastward towards the western Pacific Ocean, westward towards the Dongsha Island and southwestward towards the South China Sea Basin. In the horizontal direction, tidal current amplitudes decrease as distance increases away from the LS; in the vertical direction, they show an obvious decreasing tendency with depth. Between the double ridges of the LS, a clockwise gyre of M2 baroclinic energy flux appears, which is caused by reflections of M2 internal tides at supercritical topographies, and resonance of M2 internal tides happens along 19.5° and 21.5°N due to the heights and separation distance of the double ridges. The total energy conversion in the LS is about 14.20 GW. 相似文献