Wind-driven interannual variability over the northeast Pacific Ocean     

Patrick F. Cummins  Gary S.E. Lagerloef 《Deep Sea Research Part I: Oceanographic Research Papers》2004,51(12):365

Interannual variability of the sea surface height (SSH) over the northeast Pacific Ocean is hindcast with a reduced-gravity, quasi-geostrophic model that includes linear damping. The model is forced with monthly Ekman pumping fields derived from the NCEP reanalysis wind stresses. The numerical solution is compared with SSH observations derived from satellite altimeter data and gridded at a lateral resolution of 1 degree. Provided that the reduced gravity parameter is chosen appropriately, the results demonstrate that the model has significant hindcast skill over interior regions of the basin, away from continental boundaries. A damping time scale of 2 to 3 years is close to optimal, although the hindcast skill is not strongly dependent on this parameter.A simplification of the quasi-geostrophic model is considered in which Rossby waves are eliminated, yielding a Markov model driven by local Ekman pumping. The results approximately reproduce the hindcast skill of the more complete quasi-geostrophic model and indicate that the interannual SSH variability is dominated by the local response to wind forcing. There is a close correspondence the two leading empirical orthogonal modes of the local model and those of the observed SSH anomalies. The latter account for over half of the variance of the interannual signal over the region.  相似文献   

Spring-spawning herring (Clupea harengus L.) in the southwestern Baltic Sea: do they form genetically distinct spawning waves?     

Hede Jorgensen  Hanne B.; Hansen  Michael Moller; Loeschcke  Volker 《ICES Journal of Marine Science》2005,62(6):1065-1075

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Distribution of nonlinear wave crests     

J. Al-Humoud  M. A. Tayfun  H. Askar 《Ocean Engineering》2002,29(15):1929-1943

The distribution of nonlinear wave crests is examined on the basis of a theoretical probability density previously given elsewhere (J. Eng. Mech. 120 (1994) 1009). Certain errors contained in the original theoretical density are corrected, and the corresponding exceedance distribution is derived. The resulting theoretical forms of the probability density and exceedance distribution are then slightly simplified and compared with nonlinear wave data gathered under hurricane conditions. The results indicate that the proposed theoretical forms describe the observed distributions of large wave crests better than the Rayleigh law. However, the quantitative accuracy of the predictions is somewhat poor, as is typical of approximate theories based on Gram–Charlier-type expansions.  相似文献   

Long Waves Associated with Bichromatic Waves   总被引：1，自引：0，他引：1  

DONG Guohai 《中国海洋工程》2001,(2):281-289

A numerical model of low frequency waves is presented. The model is based on that of Roelvink (1993), but the nu-merical techniques used in the solution are based on the so-called Weighted-Average Flux (WAF) method with Time-Operator-Splitting (TOS) used for the treatment of the source terms. This method allows a small number of computational points to be used, and is particularly efficient in modeling wave setup. The short wave (or primary wave) energy equation is solved with a traditional Lax-Wendroff technique. A nonlinear wave theory is introduced. The model described in this paper is found to be satisfactory in modeling low frequency waves associated with incident bichromalic waves.  相似文献   

Separation of Waves by Interpolation Method     

孙鹤泉  王永学 《中国海洋工程》2003,17(1)

1 .ＩｎｔｒｏｄｕｃｔｉｏｎＴｏｍｅａｓｕｒｅｔｈｅｒｅｆｌｅｃｔｉｏｎｏｆｉｎｃｉｄｅｎｔｗａｖｅｓｐｒｏｄｕｃｅｄｂｙａｐｈｙｓｉｃａｌｍｏｄｅｌｉｎａｗａｖｅｆｌｕｍｅｉｓａｃｏｍｍｏｎｐｒｏｂｌｅｍｗｉｔｈｐｈｙｓｉｃａｌｔｅｓｔｓｏｆｗａｖｅａｃｔｉｏｎｏｎｃｏａｓｔａｌｓｔｒｕｃｔｕｒｅｓ .Ｗａｖｅｓｇｅｎｅｒａｔｅｄｂｙｔｈｅｗａｖｅ ｍａｋｅｒｐｒｏｐａｇａｔｅｆｏｒｗａｒｄｉｎｔｈｅｗａｖｅｆｌｕｍｅａｎｄａｒｅｒｅｆｌｅｃｔｅｄｂｙｔｈｅｐｈｙｓｉｃａｌｍｏｄｅｌ,ａｎｄｔｈｅ…  相似文献   

Statistics of nonlinear wave crests and groups   总被引：1，自引：0，他引：1  

M. Aziz Tayfun   《Ocean Engineering》2006,33(11-12):1589-1622

Groups of large nonlinear waves with sharper higher crests can pose hazards to ships, induce harbor resonance and cause wave-overtopping of fixed and floating structures. Past interest in wave groups has mostly been focused on the statistics and modeling of linear wave groups. Studies on nonlinear wave groups are surprisingly few, and address deep water waves only. Here, statistics of nonlinear wave crests and wave-crest groups in deep and transitional water depths are considered, using an appropriate second-order representation for crest heights and the continuous wave-envelope approach. In particular, theoretical expressions describing the statistics of nonlinear wave crests and their groups are posed in the form of a simple second-order transformation of well-known results on linear waves. Predictions from the transformation so posed compare well with nonlinear wave data gathered in the North Sea, and demonstrate that nonlinearities do affect the statistics of large wave crests and their groups significantly.  相似文献   

Three-dimensional numerical simulation of obfique wave action on vertical walls     

LI Benxia YU Xiping YU Yuxiu 《海洋学报(英文版)》2006,25(1):147-153

A three-dimensional numerical model based on the potential theory was developed to study the oblique wave action on vertical walls. A source term inside the domain was used to generate incident waves and outgoing waves were dissipated by sponge layers and transmitted by radiation boundaries. The finite difference method was used to solve the governing equations and boundary conditions in the regular transformed domain in σ-coordinate. Satisfactory agreements between the numerical predictions and experimental results of wave force were obtained. It is concluded that the maximum wave force acting on the vertical walls is induced by the obliquely incident waves rather than the normally incident waves.  相似文献   

双层局部开孔板沉箱对波浪反射的理论研究   总被引：1，自引：0，他引：1  

李玉成  刘洪杰滕斌 《海洋工程》2005,23(1):18-27,32

提出了一种用于研究由双层开孔板和一个不透水后板的开孔结构对斜向波反射率的理论分析方法。整个流域被分成三个子域，在每个子域内应用特征函数展开法以得到该域内包含未知展开系数的势函数的表达式，在速度势的展开中，考虑了非传播模态波浪的影响。通过匹配开孔板处的边界条件可以求解待定的展开系数，继而求解双层开孔板防波堤结构对斜向波的反射率。数值计算结果与试验结果进行了比较，符合较好。并进一步讨论了几个重要因素对反射系数的影响。  相似文献   

Analytic Solution of Interaction Between Surface Waves and Floating Elastic Plates with Elastic End-Restraints     

赵存宝张嘉钟  邢海燕黄文虎 《中国海洋工程》2007,21(1):23-38

Based on the dynamic theories of water waves and Mindlin plates,the analytic solution of interaction between surface waves and two-dimensional floating elastic plates with edge-restraint is constructed by use of the Wiener-Hopf technique.Firstly,without regard for elastic edge restraint,the wave-induced responses of elastic floating plate analyzed by the present method are in good agreement with the results from literature and experimental results.Therefore,it can be shown that the present method is valid.Secondly,three end-restraint cases(i.e.,the left-end elastic restraints,the both-end elastic restraints,and the right-end elastic restraints)are proposed to reduce the vibration of floating plates,in which the spring is used to connect the sea bottom and the floating plate's left(or right)edge.The relations between the spring stiffness and the parameters of wave-induced responses of floating plates are discussed.Moreover,the effective method to reduce the vibration of floating elastic plates can be obtained through comparison.  相似文献   

Numerical Investigation on the Generation and Propagation of Irregular Waves in A Two-Dimensional Wave Tank     

Ruey-syanSHIH Chung-renCHOU JohnZ.YIM 《中国海洋工程》2004,18(4):551-566

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