关于波浪破碎特性的研究     

王谅  金鹰  李宇  丁坚 《海洋工程》1995,(3)

有关波浪破碎问题的研究是海岸工程界十分关注的课题。本文列举了前人有关波浪破碎特性方面的研究成果；分析了波浪破碎前后波高的变化规律，作出了适当的假定；并考虑了动床海滩坡度、底摩擦以及紊动对波浪破碎特性的影响。应用波动能量耗散率理论，并结合孤立波理论的有关公式，作者推导了计算动床海滩上破碎指标ｒ_ｂ的公式，并进而给出破碎水深ｈ_ｂ与破碎波高Ｈ_ｂ的计算公式。通过不同规模实验水槽的资料验证表明，这组计算式具有广泛的实用性。  相似文献   

世界大洋长历时局地风速和有效波高的统计与分析   总被引：1，自引：0，他引：1  

李陆平 《海洋科学进展》1991,(1)

本文基于美国海军测地卫星高度计提供的全球范围长历时局地平均风速和有效波高资料进行统计分析,结果表明,世界大洋长历时局地平均风速和有效波高有明显的相关性,其散布点系统地位于Wilson提出的深水充分成长风浪平均风速和有效波高经验曲线之上;并从能量叠加平衡方程,近似定量估计出大洋中长历时涌浪有效波高与局地平均风速的关系。  相似文献   

Groupiness of Sea Waves and Their Characteristic Parameters   总被引：1，自引：0，他引：1  

Yu Yuxiu Gui Manhai Professor  Dept. of Civil Eng. Dalian University of Technology  Dalian Master  Dept. of Civil Eng. Dalian University of Technology  Dalian 《中国海洋工程》1996,(1)

Three methods for studying wave groups and their main parameters for describing wave groupiness are reviewed in this paper. Then they are analyzed and compared combined with field data from both aspects of group height and group length. A method and two parameters that can describe wave groupiness are suggested. The groupiness parameters of sea waves at three field stations are given. The effects of groupiness on both distributions of the wave height and the phase of component waves are investigated. The effects of datum length on the calculated value of grouping parameters are also discussed.  相似文献   

太平洋波高成份研究     

韩树宗  朱大勇  郭佩芳 《海洋湖沼通报》2003,(4):14-21

利用Topex／Poseidon卫星高度计1992年10月到1998年12月连续75个月，230个重复周期的有效波高资料对南北太平洋的波高成份进行了分析，结果显示所有的月份，频数密度峰值对应的波高成份因子为1．4，以赤道太平洋海域最高为1．6，南北太平洋海域为1．2左右。7、8、9、10月份太平洋涌浪成份占频数密度累积率的比例大于95％，其余各月占90%左右，表明太平洋海域波高成份以涌浪为主。  相似文献   

Sea State and Rain: A Second Take on Dual-Frequency Altimetry     

Graham D. Quartly 《Marine Geodesy》2004,27(1):133-152

TOPEX and Jason were the first two dual-frequency altimeters in space, with both operating at K_u- and C-band. Thus, each gives two measurements of the normalized backscatter, σ⁰, (from which wind speed is calculated) and two estimates of wave height. Departures from a well-defined relationship between the K_u- and C-band σ⁰ values give an indication of rain. This study investigates differences between the two instruments using data from Jason's verification phase. Jason's K_u-band estimates of wave height are ∼1.8% less than TOPEX's, whereas its σ⁰ values are higher. When these effects have been removed the root mean square (rms) mismatch between TOPEX and Jason's K_u-band observations is close to that for TOPEX's observations at its two frequencies, and the changes in σ⁰ with varying wave height conditions are the same for the two altimeters. Rain flagging and quantitative estimates of rain rate are both based on the atmospheric attenuation derived from the σ⁰ measurements at the two frequencies. The attenuation estimates of TOPEX and Jason agree very well, and a threshold of-0.5 dB is effective at removing the majority of spurious data records from the Jason GDRs. In the high σ⁰ regime, anomalous data can be caused by processes other than rain. Consequently, for these low wind conditions, neither can reliable rain detection be based on altimetry alone, nor can a generic rain flag be expected to remove all suspect data.  相似文献   

Derivation of coastal wind and wave parameters from offshore measurements of TOPEX satellite using ANN     

Ruchi Kalra  M.C. Deo 《Coastal Engineering》2007

The paper discusses an artificial neural network (ANN) approach to project information on wind speed and waves collected by the TOPEX satellite at deeper locations to a specified coastal site. The observations of significant wave heights, average wave period and wind speed at a number of locations over a satellite track parallel to a coastline are used to estimate corresponding values of these three parameters at the coastal site of interest. A combined network involving an input and output of all the three parameters, viz., wave height, period and wind speed instead of separate networks for each one of these variables was found to be necessary in order to train the network with sufficient flexibility. It was also found that network training based on statistical homogeneity of data sets is essential to obtain accurate results. The problem of modeling wind speeds that are always associated with very high variations in their magnitudes was tackled in this study by imparting training in an innovated manner.  相似文献   

Euclid贴近度聚类分析鉴别海面溢油   总被引：3，自引：0，他引：3  

徐恒振  尚龙生  周传光  刘彤 《海洋与湖沼》1995,26(6):625-631

于１９８６年对我国常见的１４种油品的１９８４年８月大连湾海面溢油进行气相色谱分析，用模糊数学方法建立Ｅｕｃｌｉｄ贴近度聚类分析的海面溢油鉴别模式提出油鉴别的Ｅｕｃｌｉｄ贴近度置信水平λｉ的模糊区概念。  相似文献   

Prediction of breaking waves with neural networks     

M. C. Deo  S. S. Jagdale 《Ocean Engineering》2003,30(9):1163-1178

The height of a wave at the time of its breaking, as well as the depth of water in which it breaks, are the two basic parameters that are required as input in design exercises involving wave breaking. Currently the designers obtain these values with the help of graphical procedures and empirical equations. An alternative to this in the form of a neural network is presented in this paper. The networks were trained by combining the existing deterministic relations with a random component. The trained network was validated with the help of fresh laboratory observations. The validation results confirmed usefulness of the neural network approach for this application. The predicted breaking height and water depth were more accurate than those obtained traditionally through empirical schemes. Introduction of a random component in network training was found to yield better forecasts in some validation cases.  相似文献   

由模拟波面统计分析波高－周期联合分布     

黎满球  陈俊昌 《热带海洋学报》1996,(3)

阐述以实测或拟合海浪谱为靶谱，用等能量分割法作波面数值模拟，从而利用模拟波面统计分析波高（Ｈ）－周期（Ｔ）联合分布。对波候的Ｈ－Ｔ联合分布、长时段海浪连续记录的Ｈ－Ｔ联合分布以及风浪、涌浪和混合浪的Ｈ－Ｔ联合分布进行了讨论。结果表明，只要已知特征波高和周期，就可反演出模拟波面，进而估测Ｈ－Ｔ联合分布情况，这对了解与各种特征波高对应的周期问题及在海洋工程应用上有一定的参考意义。  相似文献   

非线性随机海浪模型的一种新形式   总被引：5，自引：1，他引：5  

刘新安  黄培基 《海洋与湖沼》1997,28(3):310-314

以反映随机海浪非线性的波面高度分布高阶矩为参量，提出一种新形式的非线性随机海浪模型，在三阶近似下具体导出其波面高度的表达工和推导出二阶谱。本文模式为Ｌｏｎｇｕｅｔ－Ｈｇｇｉｎｓ模式的另一种新的数学表示。  相似文献