南海北部—观测点内潮特征的初步分析   总被引：2，自引：0，他引：2  

邱章  徐锡祯  龙小敏 《热带海洋学报》1996,(4)

采用功率谱分析、调和分析等方法，对南海北部－观测点连续９ｄ（１９８８年５月８—１６日）的温度。盐度和海流及跨越该期间较长的（１９８８年４月２４日－７月２２日）潮位资料进行了分析研究。结果表明，观测点存在着一种内潮现象，其波动的周期在２４ｈ左右，它传播的方向大体是偏北。  相似文献   

分层海洋的内孤立波     

徐肇廷 《中国海洋大学学报(自然科学版)》1989,(3)

本文从流体力学基本方程组出发,在非地转条件下导得了分层海洋的内孤立波方程—Kbv和mKdv方程,证实了在非地转条件下,一类海洋非线性波动是可以严格满足内孤立波方程的。在地转条件下采用f平面近似导出了KdV方程的演化形式一有源KdV方程,地转的影响含于源项中。由初步的分析得出,f对KdV方程的影响是微弱的。由已得的KdV和mKdV方程的解可知,内孤立波与线性波有着本质差别。  相似文献   

Aspects of Deep Ocean Mixing     

Chris Garrett  Louis St. Laurent 《Journal of Oceanography》2002,58(1):11-24

The turbulent motions responsible for ocean mixing occur on scales much smaller than those resolved in numerical simulations of oceanic flows. Great progress has been made in understanding the sources of energy for mixing, the mechanisms, and the rates. On the other hand, we still do not have adequate answers to first order questions such as the extent to which the thermohaline circulation of the ocean, and hence the earth's climate, is sensitive to the present mixing rates in the ocean interior. Internal waves, generated by either wind or flow over topography, appear to be the principle cause of mixing. Mean and eddy flows over topography generate internal lee waves, while tidal flows over topography generate internal tides. The relative importance of these different internal wave sources is unknown. There are also great uncertainties about the spatial and temporal variation of mixing. Calculations of internal tide generation are becoming increasingly robust, but we do not know enough about the subsequent behavior of internal tides and their eventual breakdown into turbulence. It does seem, however, that most internal tide energy flux is radiated away from generation sites as low modes that propagate over basin scales. The mechanisms of wave-wave interaction and topographic scattering both act to transfer wave energy from low modes to smaller dissipative scales. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

High Frequency Current Fluctuations and Cross-shelf Flows around the Pycnocline near the Shelf Break in the East China Sea     

In-Seong Han  Koichiro Kamio  Takeshi Matsuno  Atsuyoshi Manda  Atsuhiko Isobe 《Journal of Oceanography》2001,57(2):235-249

Relation between internal waves with short time scale and density distribution near the shelf break in the East China Sea is studied utilizing moored current meters, thermometers and conductivity-temperature-depth (CTD) casts. A well developed pycnocline was frequently observed around 150–200 m depth near the shelf break accompanied with the development of internal waves with short time scale. During the cruise in May 1998, the intensified internal wave motion with short time scale and the distinct offshore flow were observed just below the lower pycnocline, which shoaled and extended above the shelf area. It is suggested that vertical mixing generated by amplified internal waves would produce cross-shelf ageostophic density current around the pycnocline. During the cruise in May 1999, on the other hand, the lower pycnocline was located offshore below the shelf break, and the internal wave motion was amplified just above the lower pycnocline. In this case, the offshore flow should be generated above the lower pycnocline, but vertical profiles of current velocity were not obtained because acoustic Doppler current profiler (ADCP) data were not available around the lower pycnocline.  相似文献   

三次样条插值在浮性频率计算中的应用     

蔡树群  甘子钧  仇德忠 《热带海洋学报》1997,(3)

在普遍利用海洋观测站标准层的温度、盐度数据估算稳定层化海水浮性频率的传统算法中引入自然三次样条插植方法，不仅可使计算结果的精度得以提高，而且还可方便地对观测深度范围内的任一水层进行插值，从而获得总体曲率最小的温度、盐度和浮性频率随深度的分布。本文以南海（13°30’N，118°30’E；9°30’N，lll°30’E）及北太平洋（40°00’N130°00’W）3个测站为例，说明了在浮性频率的传统算法中引入自然三次样条插值法的可行性。  相似文献   

Baroclinic Buoyancy-Inertia Joint Stability Parameter     

Hideo Kawai 《Journal of Oceanography》2005,61(2):235-246

At present, the barotropic buoyant stability parameter has been derived from a vertical virtual displacement of a water parcel. The barotropic inertial stability parameter in the eccentrically cyclogeostrophic, basic current field was derived in 2003 from a horizontal cross-stream virtual displacement of a parcel. By expressing acceleration of a parcel due to a virtual displacement, which is arbitrarily sloping within a vertical section across the basic current, in terms of natural coordinates, we derived the vertical component of baroclinic buoyant stability parameter B ₂ ², the horizontal component of baroclinic inertial stability parameter I ₂ ², the baroclinic joint stability parameter J ², its buoyant component B ² and its inertial component I ². B ² is far greater than I ₂ ², and when neglecting relative vorticity except for vertical shear, a downward convex curve of J ² plotted against the slope of a virtual displacement follows a trend of B ² curve. If a parcel displaces along a horizontal surface or an isopycnal surface, however, B ² vanishes, and J ² becomes equal to I ². Actual parcel is apt to displace not only along the bottom slope, but also along the sea surface and an isopycnal interfacial surface, which is approximately equivalent to an isentropic surface, preferred by lateral mixing and exchange of momentum. Such actual displacement makes B ² vanishing, and grants I ² an important role. The present analysis of I ² examining effects due to curvature and horizontal and vertical shear vorticities are useful in deepening our understanding of baroclinic instability in actual oceanic streams.  相似文献   

The Effect of Internal Fluid on the Response of Vortex-Induced Vibration of Marine Risers   总被引：5，自引：1，他引：5  

郭海燕  王元斌傅强 《中国海洋工程》2004,18(1):11-20

Based on Iwan‘s wake oseillator model developed with the classical van der Pol equalion, the differential equation for the response of the vortex-induced vihration (VIV) of the riser considering the effect of the internal flowing fluid and the external marine environmental condition is derived. The effect of the intermal flowing fluid on the response of VIV of the riser is studied by means of the Finite Element Method. The results show that the effect of the internal fluid velocity on the VIV of the riser is strong when the natural frequency of the riser is close to the vortex shedding frequency. In addition, the increase of the top tension can decrease the sensitivity of the riser to the internal fluid velocity.  相似文献   

两层分层流体中初始内孤立波分裂的数值研究     

徐肇廷  贾村  陈旭  文凡 《中国海洋大学学报(自然科学版)》2006,36(3):345-348

本文导得了1个研究内波分裂的射线型二维KdV方程。利用这一方程的一维退化方程进行了实验室尺度下孤立子型内波分裂的数值研究。数值结果表明,深水区的初始内孤立波和实测的内孤立波(内潮)在通过陆坡区时都会产生分裂,并在陆架上(浅水区)生成一内孤立子波列。这表明在实际海洋条件下,深海区内潮的分裂是陆架上海洋内孤立子波包(或波列)生成的主要机制之一。  相似文献   

波群作用于垂直桩柱的峰力统计性质     

徐立论  陈志军  焦海英 《中国海洋大学学报(自然科学版)》1994,(1)

研究具有窄谱和Ｗｅｉｂｕｌｌ波高分布的波群对非线性桩柱系统作用力的统计性质。求得了桩桩的波浪峰力的各种特征值及其比值。指出这些数值不仅是阻力一惯性力参数ｂＨ的函数，也随着波群因子而变化。本文模式更具广泛性。文中给出了一系列计算图表，可从理论计算波群作用于桩柱的波浪峰力。  相似文献   

卫星高度计海上定标场及定标方法研究进展   总被引：1，自引：0，他引：1  

张有广  林明森 《海洋通报》2007,26(3):87-92,116

介绍了卫星高度计定标中海面高度和后向散射系数的定标方法。在后向散射系数的定标中介绍了利用有源定标器和微波辐射计定标两种方法。结合卫星高度计的特点,提出了海上定标场选取所需注意的问题,并介绍了目前比较成功的几个定标场及其定标结果,旨在为我国今后发射的卫星高度计绝对定标和定标场的选取提供依据。  相似文献