Spatial and Temporal Variations of Sound Speed at the PN Section   总被引：3，自引：0，他引：3  

Lian-Gang Lü  Hong-Xia Chen  Ye-Li Yuan 《Journal of Oceanography》2004,60(4):673-679

Gridded sound speed data were calculated using Del Grosso's formulation from the temperature and salinity data at the PN section in the East China Sea covering 92 cruises between February 1978 and October 2000. The vertical gradients of sound speed are mainly related to the seasonal variations, and the strong horizontal gradients are mainly related to the Kuroshio and the upwelling. The standard deviations show that great variations of sound speed exist in the upper layer and in the slope zone. Empirical orthogonal function analysis shows that contributions of surface heating and the Kuroshio to sound speed variance are almost equivalent. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

动力定位系统与单波束测深仪在科考船定点作业中的应用     

张彬彬  张道建  张海泉  刘凯  张学贤  卢永平 《海洋通报》2020,39(6):651-656

科考船定点作业时会受到海洋风、涌、浪、流等外界环境因素影响，导致工作效率降低，原位测量精度下降，甚至影响作业安全。动力定位系统 （DP） 具有自动定位功能，能够抵抗外界环境因素的影响，可实现科考船高精度定点控位。 单波束测深仪不仅可以测量水深，也可反映水下设备深度信息，可以起到辅助监控水下设备功能。本文在介绍定点作业施工现状与局限性的基础上，分析 DP 系统与单波束测深仪工作原理，以“向阳红 01”船为载体，在定点作业时开启 DP 系统与单波束测深仪，发现该方法可以提高科考船定点作业工作效率、原位测量精度并保障作业安全，可为其他科考船定点作业提供参考。  相似文献   

Dissipation source function and an improvement to LAGFD-WAM model   总被引：1，自引：0，他引：1  

Yuan Yeli  Hua Feng  Pan Zengdi  Sun Letao 《海洋学报(英文版)》1992,11(4):471-481

In this paper, a new theoretical expression of dissipation term is presented on the basis of statistical model of breaking wave, which is an improvement to LAGFD-WAM wave model. The computational results in three typical wind fields show a good improvement to LAGFD-WAM model and a better accuracy in comparison with the observed data in the South China Sea.  相似文献   

Monitoring the Kuroshio Extension with Dynamically Constrained Synthesis of the Acoustic Tomography, Satellite Altimeter and in situ Data     

Konstantin V. Lebedev  Max Yaremchuk  Humio Mitsudera  Iwao Nakano  Gang Yuan 《Journal of Oceanography》2003,59(6):751-763

A finite-difference quasigeostrophic (QG) model of an open ocean region has been employed to produce a dynamically constrained synthesis of acoustic tomography and satellite altimetry data with in situ observations. The assimilation algorithm is based upon the 4D variational data interpolation scheme controlled by the model's initial and boundary conditions. The data sets analyzed include direct and differential travel times measured at the array of five acoustic transceivers deployed by JAMSTEC in the region of the Kuroshio Extension in 1997, Topex/Poseidon altimetry, CTD soundings, and ADCP velocity profiles. The region monitored is located within the area 27.5°–36.5°N, 143°–155°. The results of assimilation show that mesoscale variability can be effectively reconstructed by five transceivers measuring direct and reciprocal travel times supported by relatively sparse in situ measurements. The misfits between model and data lie within the observational error bars for all the data types used in assimilation. We have compared the results of assimilation with the statistical inversion of travel time data and analyzed energy balances of the optimized model solution. Energy exchange between the depth-averaged and shear components of the observed currents reveals a weak decay of the barotropic mode at the rate of 0.2 ± 0.7⋅10⁻⁵ cm²/s³ due to topographic interaction. Mean currents in the region are unstable with an estimate of the available potential energy flux from the mean current to the eddies of 4.7 ± 2.3⋅10⁻⁵ cm²/s³. Kinetic energy transition has the same sign and is estimated as 2.8 ± 2.5⋅10⁻⁵ cm²/s³. Potential enstrophy is transferred to the mesoscale at a rate of 5.5 ± 2.7⋅10⁻¹⁸ s⁻³. These figures provide observational evidence of the properties of free geostrophic turbulence which were predicted by theory and observed in numerical experiments. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

复合加载模式作用下地基承载性能数值分析   总被引：11，自引：3，他引：11  

栾茂田  赵少飞  袁凡凡  吕爱钟  武科 《海洋工程》2006,24(1):34-40

确定竖向荷载(V)、水平荷载(H)和力矩(M)共同作用下建筑物地基的破坏模式及在荷载空间(H,V,M)中的破坏包络面是地基设计中的关键问题。为提高Swipe试验方法计算精度,提出了改进方案,进而利用有限元方法分析了复合加载模式作用下均质粘性土地基上条形基础的破坏包络面。计算表明,基于改进Swipe试验方法的数值模拟结果明显好于常规Swipe试验方法。针对海洋工程中实际复合加载模式的特点,探讨了竖向荷载分量V对地基破坏模式和H-M荷载平面上的破坏包络线的影响,结果表明竖向荷载分量显著地改变了地基的破坏模式及包络线的形状。  相似文献   

海洋平台复杂节点阴极保护电位分布的有限元法计算   总被引：1，自引：0，他引：1  

王爱萍  杜敏  陆长山  曹圣山  王庆璋 《中国海洋大学学报(自然科学版)》2007,37(1):129-134

了解阴极保护电位分布是合理设计阴极保护工程的必要条件和评价阴极保护效果的重要依据。本文应用有限元素法(FEM)计算海洋平台复杂节点表面的阴极保护电位分布。在实验室通过边界条件试验建立数学模型,计算海水中被保护的I,Y,K型复杂节点电位分布情况。计算结果与测量结果吻合得很好,说明FEM能够应用于海洋平台复杂节点阴极保护电位分布的计算,所获得的边界条件合理。  相似文献   

湿地水文模型浅析   总被引：1，自引：0，他引：1  

朱爱美  叶思源  卢文喜 《海洋地质前沿》2006,22(9):27-31

介绍了湿地系统模型的研究现状。分别阐述湿地水量模型、地表及地下水模型、溶质运移模型、蒸散模型及泥沙运移模型,并对当前湿地综合模型系统进行评述,指出建立湿地模型的意义及存在的问题。  相似文献   

GPS测高技术在无验潮水深测量中的应用   总被引：8，自引：5，他引：8  

欧阳永忠  陆秀平  孙纪章  黄谟涛  翟国君  许家琨  申家双  王克平  刘传勇  侯世喜 《海洋测绘》2005,25(1):6-9,13

应用双频GPS动态后处理高精度定位技术，建立了一套完整的GPS无验潮海洋深度测量作业模式，通过海上试验与传统作业模式作了数值分析比较，结果表明，该作业模式不仅无需验潮，而且能够有效消除传统作业模式中船只动态吃水和涌浪等因素对测量成果的影响，显著提高水深测量成果的精度。  相似文献   

地震勘探在不同地质条件下的新应用     

卢占武  张宏远 《海洋地质前沿》2005,21(4):28-32,i002

20世纪末，地震勘探技术在油气勘探、煤田勘探、工程勘探等多方面的应用都有了突飞猛进的发展。总结了近年来地震勘探在岩性、沉积相、构造体系等不同地质条件下的应用实例，用以说明地震勘探的多用性及其强大的生命力。  相似文献   

晚中生代─新生代南海周缘地块运动与南海演化   总被引：1，自引：0，他引：1  

袁友仁  杨树康  汤贤赞  王保贵  侯红明  柳枞阳 《热带海洋学报》1994,(2)

报道了由华南几个盆地的古地磁数据综合而得的反映该区白垩纪以来古纬度变化曲线，结合Ｓｃｈｍｉｄｔｋｅ等（１９９０）发表的加里曼丹１５０Ｍａ以来的古地磁数据，表明华南与加里曼丹在４０Ｍａ前具有大致相同的古纬度变化史，差异仅出现在距今３０Ｍａ前后和１０Ｍａ以来。若此趋势可靠，则可作出下列推断：（１）南海的扩张只能发生在距今３０Ｍａ附近或１０Ｍａ以后华南与加里曼丹反向运动时期；距今３０Ｍａ的扩张已被广为接受；（２）华南与加里曼丹之向可能存在的古南海只能在９１Ｍａ之前存在；（３）南海演化可能存在两期扩张。南海的拟合可通过沿３５００ｍ等深线的先道时针旋转、后北向平移两个步骤完成。这与Ｈａｙａｓｈｉｄａ等（１９９１）提出的日本海张开与扩张模式很相似，提示东亚边缘海的形成和演化可能具有同样的机制。华南距今５０Ｍａ以来的古纬度变化与Ｔａｐｐｏｎｎｉｅｒ（１９８２）的传播挤出构造模式所预期的基本吻合，表明距今５０Ｍａ以来华南古纬度变化的运动学机制可用Ｔａｐｐｏｎｎｉｅｒ模式作解释。  相似文献