Numerical Experiment on Two-Dimensional Line Thermal     

J.H.W.LEE  G.Q.CHEN 《中国海洋工程》2002,16(4):453-467

The time evolution of a two-dimensional line thermal-a turbulent flow produced by an initial element with signifi-cant buoyancy released in a large water body, is numerically studied with the two-equation k - e model for turbulence closure. The numerical results show that the thermal is characterized by a vortex pair flow and a kidney shaped concentra-tion structure with double peak maxima; the computed flow details and scalar mixing characteristics can be described by self-similar relations beyond a dimensionless time around 10. There are two regions in the flow field of a line thermal: a mixing region where the concentration of tracer fluid is high and the flow is turbulent and rotational with a pair of vortex eyes, and an ambient region where the concentration is zero and the flow is potential and well-described by a model of doublet with strength very close to those given by early experimental and analytical studies. The added virtual mass coeffi-cient of the thermal motion is found to be approximat  相似文献   

Predictability of Interannual Variability in the Kuroshio Transport South of Japan Based on Wind Stress Data over the North Pacific   总被引：1，自引：3，他引：1  

Kiyoshi Tanaka  Motoyoshi Ikeda  Yukio Masumoto 《Journal of Oceanography》2004,60(2):283-291

It is expected that a roughly two-year forecast of the Kuroshio transport variation can be made from a past record of wind stress data over the ocean, since it takes nearly ten years for the first-mode baroclinic Rossby wave to traverse the entire basin in the midlatitude North Pacific (∼30°N). We therefore investigated the predictability using an ocean general circulation model driven by the wind stress data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. Referring to a hindcast experiment as the control run, we carried out fifteen forecast experiments, the initial conditions of which are taken from the hindcast experiment at intervals of two years during the period from the end of 1969 to the end of 1997. Each of the forecast experiments is driven only by wind stress in the year preceding each experiment. The forecasted Kuroshio transport anomaly south of Japan agrees better with the hindcasted one during the first two years of the forecast in most cases. In some cases, however, significant disagreements occur, most of which are likely due to larger unpredictable variations caused by wind stress anomalies near Japan. At the end of forecast year 2, the anomaly correlation coefficient is about 0.7, and rms of the forecast error is smaller than rms of the hindcasted anomaly. These results indicate that the prediction of the interannual variability in the Kuroshio transport could be made two years in advance at a statistically significant level. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Application of LICOM to the numerical study of the water exchangebetween the South China Sea and its adjacent oceans   总被引：8，自引：1，他引：8  

CAI Shuqun  LIU Hailong  LI Wei  LONG Xiaomin 《海洋学报(英文版)》2005,24(4):10-19

1 IntroductionThe South China Sea (SCS) is the largestmarginal sea in the western Pacific (see Fig. 1). It con-nects with the SCS through the Taiwan Strait, with thePacific through the Luzon Strait, with the Sulu Seathrough the Mindoro and Balabac Straits and with theJava Sea and Andaman Sea through the Sunda Shelf(For convenience, here we refer to the section at 1.5°N,Fig. 2). It is shown that the seasonal SCS circulation ismostly affected by the summer/winter monsoon, andthe no…  相似文献   

Influence of Current Width Variation on the Annual Mean Transport of the East Sakhalin Current: A Simple Model     

Yoichi?ShimadaEmail author  Atsushi?Kubokawa  Kay?I.?Ohshima 《Journal of Oceanography》2005,61(5):913-920

Recent observations suggest that the annual mean southward transport of the East Sakhalin Current (ESC) is significantly larger than the annual mean Sverdrup transport. Motivated by this observational result, transport of a western boundary current has been investigated using a simple numerical model with a western slope. This transport is defined as the instantaneous barotropic transport integrated from the western boundary to the offshore point where the barotropic velocity vanishes. The model, forced by seasonally varying wind stress, exhibits an annual mean of the western boundary current transport that is larger than that of the Sverdrup transport, as observed. The southward transport from October to March in the model nearly equals the instantaneous Sverdrup transport, while the southward transport from April to September decreases slowly. Although the Sverdrup transport in July vanishes, the southward transport in summer nearly maintains the annual mean Sverdrup transport, because the barotropic Rossby wave cannot intrude on the western slope. This summer transport causes the larger annual mean. Although there are some uncertainties in the estimation of the Sverdrup transport in the Sea of Okhotsk, the seasonal variation of the southward transport in the model is qualitatively similar to the observations.  相似文献   

Remote Sensing Analysis of the Suspended Sediment Transport in Lingdingyang   总被引：1，自引：0，他引：1  

You Yuming Hou Min Senior Engineer  River  Harbour Department  Nanjing Hydraulic Research Institute    Nanjing Assistant Engineer  River  Harbour Department  Nanjing Hydraulic Research Institute    Nanjing 《中国海洋工程》1992,(3)

- The data of landsat TM of multi-temporal for Lingdingyang Estuary, Pearl River in China is firstly used with suspended sediment concentration of field measurement to establish a correlative model equation. After the ratio processing of TM data and atmospheric correction, the images of suspended sediment concentration of different temporals are exported from the image processing systems AREIS II and III. These images express the characteristics of suspended sediment distribution, the mode of sediment transport and the extent of dispersion under the actions of tidal current and wind condition of different seasons.  相似文献   

白沙河地下水资源管理模型     

刘贯群  邱汉学  焦超颖 《中国海洋大学学报(自然科学版)》1994,(Z3)

针对白沙河地下水含水层的内部结构和本区开采特点以及已出现的环境问题，建立了地下水资源管理模型，确定了优化开采方案。该管理模型针对本区每年２个管理时段的长度及其开采量均不同的特点，导出了新的响应矩阵的公式。管理模型的建立有助于对该区地下水的合理开采。  相似文献   

Modeling bed-load transport of coarse sediments in the Great Bay Estuary, New Hampshire   总被引：1，自引：0，他引：1  

A. Bilgili  M. R. Swift  D. R. Lynch  J. T. C. Ip 《Estuarine, Coastal and Shelf Science》2003,58(4):937-950

Current, sea level and bed-load transport are investigated in the Lower Piscataqua River section of the Great Bay Estuary, New Hampshire, USA—a well-mixed and geometrically complex system with low freshwater input, having main channel tidal currents ranging between 0.5 and 2 m s⁻¹. Current and sea level forced by the M₂M₄M₆ tides at the estuarine mouth are simulated by a vertically averaged, non-linear, time-stepping finite element model. The hydrodynamic model uses a fixed boundary computational domain and accounts for flooding–drying of tidal flats by making use of a groundwater component. Inertia terms are neglected in comparison with pressure gradient and bottom friction terms, which is consistent with the observed principal dynamic balance for this section of the system. The accuracy of hydrodynamic predictions in the study area is demonstrated by comparison with four tidal elevation stations and two cross-section averaged current measurements. Simulated current is then used to model bed-load transport in the vicinity of a rapidly growing shoal located in the main channel of the lower system. Consisting of coarse sand and gravel, the shoal must be dredged every five to eight years. Two approaches are taken—an Eulerian parametric method in which nodal bed-load flux vectors are averaged over the tidal cycle and a Lagrangian particle tracking approach in which a finite number of sediment particles are released and tracked. Both methods yield pathways and accumulations in agreement with the observed shoal formation and the long-term rate of sediment accumulation in the shoal area.  相似文献   

Sensitivity to stress of the estuarine bivalve Macoma balthica from areas between the Netherlands and its southern limits (Gironde)     

H. Hummel  C. Amiard-Triquet  G. Bachelet  M. Desprez  J. Marchand  B. Sylvand  J.C. Amiard  H. Rybarczyk  R.H. Bogaards  J. Sinke  Y. De Wit  L. De Wolf 《Journal of Sea Research》1996,35(4):315-321

Variation in the sensitivity to stress of Macoma balthica was measured in several French and Dutch estuaries. For adult and juvenile Macoma balthica exposed to copper under conditions of starvation, differences in mortality rate, condition, glycogen, burrowing rate and copper content were assessed. No significant differences were observed between adults and juveniles; the influence of treatment and origin was always evident. Animals from the most southern estuaries, Loire and Gironde, near to the species's southern limit of distribution, showed, in the field, the strongest deviations for the ecophysiological traits measured, and were in the experiments the most sensitive to stress.  相似文献   

A computer simulation model for predicting rates and scales of movement of demersal fish on the European continental shelf   总被引：1，自引：1，他引：1  

Arnold  G. P.; Holford  B. H. 《ICES Journal of Marine Science》1995,52(6):981-990

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菲律宾海热含量分布及其变化的初步探讨   总被引：2，自引：0，他引：2  

白虹  胡敦欣 《海洋科学》1989,13(3):7-12

本文利用1986年及1987年秋季在菲律宾以东海域进行的CTD观测资料,分析了该海域上层海水热含量分布及变化,得出,热含量由南向北随纬度逐渐增大,这主要是北赤道流引起的等温线自南向北下倾造成的,另外也与南部和北部的冷涡和暖涡有关。本文认为,两年里热含量的差异可能与1986年生成的El Nin有关。另外,北太平洋赤道流体积输送量的变化与菲律宾海热含量的变化也有一定的联系。  相似文献