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1.
W. J. Hastie 《新西兰海洋与淡水研究杂志》2013,47(4):507-515
Wave data are presented for Timaru, New Zealand, based on instrumental records collected between October 1981 and October 1982. Significant wave height ranged from 0.32–3.33 m with a mean value of 0.97 m. Significant wave period ranged from 5–17 s with a mean value of 10 s. The maximum wave height recorded was 6.30 m. A marked variation was found between summer and winter conditions. Winter months displayed a much greater range of wave conditions, significant heights were generally higher and significant periods longer. 相似文献
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本文介绍了作者们设计并制造的小型内波实验水槽系统,它包括水槽、双缸法供水系统、造波与消波装置以及量测与显示手段。实验表明,此系统性能良好,可进行内波科研与教学实验。 相似文献
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I~IOXdifferent tabes of submerged structures restricting wave development are extensively appliedin coastal and barber engineering. Generally speaking, the submerged structures are classified intothree types (see Fig. 1 ): a submerged horizontal plate (fixed submerged structure), a submergedbreakwater (rectangular or trapezoidal) and a step-take structure (toPOgraphy). In order to get aclear understanding of the characteristics of wave motion around submemed structures, manyFig. 1. Fol'InS… 相似文献
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为了解杭州湾北部波浪特性,利用杭州湾北部一年实测波浪资料,统计分析该地区的波参数变化特征,运用回归分析获得波参数之间的相关关系,并用谱参数及波谱形态分析了实测波浪频谱的变化特性。结果表明,与杭州湾南部海域波浪特性明显不同之处是热带气旋对本观测水域波浪的影响强度大于冬季季风的影响强度,较大波浪主要由热带气旋引起,并且路径相似的热带气旋在杭州湾南、北部测点引起的最大波浪其参数较为接近。研究水域常浪向分布在东东北至东南向,强浪向主要分布在东东北方向。研究成果可为河口海湾相关工程的设计建造和沿海防灾减灾提供重要参考。 相似文献
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Saleh Abdalla 《Marine Geodesy》2015,38(3):365-380
SARAL/AltiKa surface wind speed (WS) and significant wave height (SWH) measurements are monitored and validated against operational European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric and wave model results in addition to available in-situ observations to access their suitability for various applications, especially SWH data assimilation. The quality of SWH is very high while that of WS is very good except for an underestimation of high wind speeds. The impact of assimilating SWH in the ECMWF Integrated Forecast System was assessed using several numerical experiments. The results show positive impact. Operational assimilation of SWH at ECMWF model is part of the forthcoming model change. 相似文献
6.
Pitch-roll buoy mean wave directions from heave acceleration, bow magnetism, and starboard magnetism
This paper describes the refinement of a previously published procedure for estimating Mean Wave Direction using azimuth, pitch, and roll derived from only the bow and starboard components of the earth magnetic field. To demonstrate the effectiveness of this refined procedure, it is applied to sensor time series records taken over a single twenty-minute period aboard a pitch-roll buoy, and results are presented. On the assumption that the method will be verified by additional data, practical means to apply it operationally are outlined. 相似文献
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The long-term trend of the sea surface wind speed and the wave height (wind wave, swell, mixed wave)in global ocean during the last 44 a 总被引：2，自引：1，他引：1
Utilizing the 45 a European Centre for Medium-Range Weather Forecasts(ECMWF)reanalysis wave data(ERA-40),the long-term trend of the sea surface wind speed and(wind wave,swell,mixed wave)wave height in the global ocean at grid point 1.5×1.5 during the last 44 a is analyzed.It is discovered that a majority of global ocean swell wave height exhibits a significant linear increasing trend(2–8 cm/decade),the distribution of annual linear trend of the significant wave height(SWH)has good consistency with that of the swell wave height.The sea surface wind speed shows an annually linear increasing trend mainly concentrated in the most waters of Southern Hemisphere westerlies,high latitude of the North Pacific,Indian Ocean north of 30 S,the waters near the western equatorial Pacific and low latitudes of the Atlantic waters,and the annually linear decreasing mainly in central and eastern equator of the Pacific,Juan.Fernandez Archipelago,the waters near South Georgia Island in the Atlantic waters.The linear variational distribution characteristic of the wind wave height is similar to that of the sea surface wind speed.Another find is that the swell is dominant in the mixed wave,the swell index in the central ocean is generally greater than that in the offshore,and the swell index in the eastern ocean coast is greater than that in the western ocean inshore,and in year-round hemisphere westerlies the swell index is relatively low. 相似文献
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An unstructured-grid, finite-volume, nonhydrostatic, parallel coastal ocean simulator 总被引：4，自引：4，他引：4
A finite-volume formulation is presented that solves the three-dimensional, nonhydrostatic Navier–Stokes equations with the Boussinesq approximation on an unstructured, staggered, z-level grid, with the goal of simulating nonhydrostatic processes in the coastal ocean with grid resolutions of tens of meters. In particular, the code has been developed to simulate the nonlinear, nonhydrostatic internal wave field in the littoral ocean. The method is based on the formulation developed by Casulli, in that the free-surface and vertical diffusion are semi-implicit, thereby removing stability limitations associated with the surface gravity wave and vertical diffusion terms. The remaining terms in the momentum equations are discretized explicitly with the second-order Adams–Bashforth method, while the pressure-correction method is employed for the nonhydrostatic pressure in order to achieve overall second-order temporal accuracy. Advection of momentum is accomplished with an Eulerian discretization which conserves momentum in cells that do not contain the free surface, and scalar advection is discretized in a way that ensures consistency with continuity, thereby ensuring local and global mass conservation using a velocity field that conserves volume on a local and global basis. The nonhydrostatic pressure field is solved efficiently using a block-Jacobi preconditioner, and while stability is limited by the internal gravity wave speed and vertical advection of momentum, applications requiring relatively small time steps due to accuracy or stability constraints are run efficiently on parallel computers, since the present formulation is written entirely with the message-passing interface (MPI). The ParMETIS libraries are employed in order to achieve a load-balanced parallel partitioning that minimizes interprocessor communication, and the grid is reordered to optimize per-processor performance by limiting cache misses while accessing arrays in memory. Test cases demonstrate the ability of the code to efficiently and accurately compute the nonhydrostatic lock exchange and internal waves in idealized as well as real domains, and we evaluate the parallel efficiency of the code using up to 32 processors. 相似文献
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利用海南东方近岸海域2014年至2015年间一整年的海浪观测资料, 分析了海浪的时间变化特征。观测时间段内, 有效波高最大值为4.03m, 平均值0.79m; 平均周期最大值为6.32s, 平均值为3.58s。该海域冬季波高较大, 秋季最小, 常浪向为SSW方向, 强浪向为WSW向。基于该长期观测数据, 文章亦研究了平均周期、有效波高之间的关系, 同时还确立了该海域波高与平均持续时间之间的关系。最后讨论了观测时间段内波浪能流密度的变化特征, 发现一年中能流密度大于2kW·m-1的频率为26%, 且从全年的计算结果来看, 观测位置处12月的波浪能较适宜开发, 但总体波浪能资源不够丰富。文章对于认识海南东方近岸海域波浪特征以及工程设计都具有重要的意义。 相似文献
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在理论分析的基础上利用根、茎、叶均可量化的植物模型,开展波浪水槽实验。通过改变实验水深、入射波高、植物分布密度等因素,研究不规则波在植物群传播时沿程波高衰减特性,利用快速傅里叶变换对不规则波频谱变化情况进行分析。结果表明,各植物模型消波效果较好,但很少出现植物消波的边界效应,不规则波沿植物群的波高变化情况多数时与Mendez理论曲线不一致,植物群各部分的波能衰减情况并无固定的变化规律。此外,波能衰减集中在谱峰频率处,且入射波高越大,透射波与入射波之间的谱峰值差值越大,但透射波的频谱宽度与入射波相比无明显变化。本研究可为采用近岸植物消波护岸提供一定的理论依据。 相似文献
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A study of sea surface wave propagation and its energy deformation was carried out using field observations and numerical experiments over a region spanning the midshelf of the South Atlantic Bight (SAB) to the Altamaha River Estuary, GA. Wave heights on the shelf region correlate with the wind observations and directional observations show that most of the wave energy is incident from the easterly direction. Comparing midshelf and inner shelf wave heights during a time when there was no wind and hence no wave development led to an estimation of wave energy dissipation due to bottom friction with corresponding wave dissipation factor of 0.07 for the gently sloping continental shelf of the SAB. After interacting with the shoaling region of the Altamaha River, the wave energy within the estuary becomes periodic in time showing wave energy during flood to high water phase of the tide and very little wave energy during ebb to low water. This periodic modulation inside the estuary is a direct result of enhanced depth and current-induced wave breaking that occurs at the ebb shoaling region surrounding the Altamaha River mouth at longitude 81.23°W. Modelling results with STWAVE showed that depth-induced wave breaking is more important during the low water phase of the tide than current-induced wave breaking during the ebb phase of the tide. During the flood to high water phase of the tide, wave energy propagates into the estuary. Measurements of the significant wave height within the estuary showed a maximum wave height difference of 0.4 m between the slack high water (SHW) and slack low water (SLW). In this shallow environment these wave–current interactions lead to an apparent bottom roughness that is increased from typical hydraulic roughness values, leading to an enhanced bottom friction coefficient. 相似文献
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Discussion on Coastal Erosion Near Xizhuang, Penglai, China 总被引：1，自引：0，他引：1
Wu Guiqiu Li Wei Professor First Institute of Oceanography State Oceanic Administration Qingdao Associate Researcher 《中国海洋工程》1994,(2)
-In this work, on the basis of the characteristics of coastal erosion near Xizhuang (Penglai, Shandong, China) and the in-situ measured data and theoretical calculation, the causes of coastal erosion there are obtained: (1) natural erosion, (2) beach sand borrowing, and (3) sand borrowing at the Dengzhou shoal near Xizhuang, which results in the loss of the function of the wave force resistance of the shoal. Since the wave energy is increased, the longshore sediment transport rate is increased. Coastal erosions are more and more serious. A scientific basis to reduced the calamity of coastal erosion in local area is presented. Some experiences are accumulated for studying coastal erosion. 相似文献
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联合SWAN模型和改进的椭圆型缓坡方程,结合考虑台湾海峡地形效应的改进藤田公式风场模型,建立了台湾海峡及近岸波浪场的数值嵌套模式.边界采用波谱离散驱动,模拟了0908号台风“莫拉克”期间台湾海峡波浪场的演变和崇武西沙湾浅水台风浪传播的物理过程.以实测数据进行单点验证表明,整个模拟过程风速的平均绝对误差为3.38 m/s,波高的平均绝对误差为0.30 m,计算结果较好地反映海峡内波浪对台风的响应过程.“莫拉克”台风登陆台湾岛时,台湾海峡有效波高最大值为5.0m;台风中心进入台湾海峡后,海峡东北部为巨浪到狂涛,有效波高最大值可达10.5 m.接近福建崇武沿岸时,偏E向台风浪向西沙湾内近岸传播,发生浅化、破碎、反射、绕射等变形现象,有效波高最大不足2 m,最小仅为0.2m,波向趋于SE向,波峰线则趋于与峡湾岸线平行;崇武闽台贸易码头附近,大部分波浪受到阻挡作用发生反射,少部分发生绕射,使得码头以北水域波浪较小,有效波高仅为0.2 ～0.6 m,对湾内避风坞起到较好的保护作用. 相似文献
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Generation and propagation of several-day period fluctuations along the southeast coast of Honshu, Japan, were investigated by analyzing sea level data and by using a numerical model. The sea level data obtained at twelve stations from Choshi to Omaezaki in fall in 1991, showed energy peaks at the 3–6 day period at the eastern stations in this coast. Time lags of the 3–6 day period fluctuations between station and station indicate westward propagation along the coast. However, the energy level of the 3–6 day period fluctuations suddenly decreased south of the Izu Peninsula. Numerical experiments using a two-layer model were performed to clarify the generation and propagation mechanism of the several-day period fluctuations by periodical wind in fall. The amplitude distributions of observed sea level were qualitatively explained by a coastal-trapped wave (CTW) in the numerical experiment. From the discussions on propagation of a free wave, CTW with the characteristics of a shelf wave generated by the wind along the northeast of the Boso Peninsula was separated into two types of wave at the southeast of the peninsula. One is an internal Kelvin wave with large interface displacement and the other is the shelf wave propagating over the northern part of the Izu Ridge. The sudden decrease in the surface displacement with the 3–6 day period observed at the western stations is considered to be due to the local effect of the wind and phase relation between the internal Kelvin wave and shelf wave. 相似文献
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A local-scale phase-resolving wave transformation model with CGWAVE is established in connection with a regional-scale coupled STWAVE-ADCIRC wave-current model for its application in the Half Moon Bay, Grays Harbor. Wave transformation from offshore to the harbor entrance is simulated by the STWAVE model which includes wave-current interaction. The STWAVE results provide incident wave conditions for the local-scale CGWAVE model at its outer boundary. A simple method is developed to take into ac- count the lateral variation of wave height in constructing the model's wave boundary conditions. The model was validated for three wave condition cases which yielded good agreement with field data. The validated model was applied to predicting nearshore waves in the Half Moon Bay and longshore transport parameters along the wave breaking line for the existing condition and three engi- neering alternatives. A comparative analysis indicated that storm waves that have a combination of long period and large height are the most destructive to the crenulate shoreline in the Half Moon Bay; both 152 m jetty extension (Alt. 2) and diffraction mound enlargement ( Alt. 3) would significantly reduce breaking wave height and longshore transport potential in the southwest comer of Half Moon Bay. 相似文献
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不规则波Boussinesq型方程的造波,消波和反射 总被引：5，自引：1，他引：4
对前人提出的造波、消波和反射边方法分析表明,其方法是极浅水波近似,不适用于任意水深的水域,本文就任意水深变化Ｂｏｕｓｓｉｎｅｓｑ型方程,提出了不规则波新的造波原理、方法和消波边界及部分反射边界波动方程,试验表明,本文提出的造波、消波和反射方程有效而可靠的。 相似文献
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