青岛附近夏季风和海面坡度对沿岸流的影响     

蒲书箴  程军  张义钧  石强  骆敬新  范文静 《海洋通报》2004,23(2):1-7

根据1999—2001年月平均海面高度资料讨论了青岛和胶州湾附近海面高度的年变化。结果表明：各验潮点夏季的海面高度普遍高于冬季的海面高度,具有明显的季节变化。此外,夏季胶州湾口外的海面高度低于胶州湾内的海面高度,表现为由北向南下倾的海面坡度。同时说明了形成这利海面坡度的原因。文章还利用动力学原理探讨了夏季风和海面坡度的动力作用,及其对月平均海流的影响,强调指出了夏季风和海面坡度所产生的压强梯度力的重要性。  相似文献   

Wave shoaling and diffraction in current over a mild-slope   总被引：2，自引：2，他引：0  

LI Yucheng  LIU Deliang  CHEN Bing  LI Linpu 《海洋学报(英文版)》2004,23(4):741-746

The wave relative frequency in the coordinate system moving with current and the angle between the direction of wave propagation and that of current are computed based on the wave dispersion relation. The current field is computed by solving the depth averaged shallow water equations. The wave field is computed by solving the mildslope equation which has taken the current‘s effect into account. A numerical model is established using a finite element method for simulating the wave shoaling and diffraction in current over a mild-slope, and the numerical results are reasonable to compare with the experimental data.  相似文献   

潮流能发电装置现状分析          下载免费PDF全文

白杨  杜敏  周庆伟  孟洁  武贺 《海洋开发与管理》2016,33(3):57-63

潮流能是海洋新能源中相对稳定且可提前预报的一类,较传统的拦坝式潮汐能开发具有环境影响小、开发规模灵活等优点,其大力发展可为海岛经济发展和海洋观测设备提供能源。文章对潮流能发电技术的研究现状进行了总结分析,详细介绍了水平轴、垂直轴和其他形式潮流能发电装置的构造以及国际上主流装置的设计参数和试验示范情况,重点对比分析了不同类型潮流能发电装置的特点和技术参数,简要总结了我国潮流能示范电站安装运行情况,并对其装置类型、导流罩作用以及布放形式等内容进行了讨论,可为我国潮流能资源的开发利用和潮流能装置测试区建设提供科学参考和设计依据。  相似文献   

Nearshore directional wave measurements by surface-following buoy and acoustic Doppler current profiler   总被引：1，自引：0，他引：1  

Paul A. Work   《Ocean Engineering》2008,35(8-9):727-737

Directional energy spectra of nearshore surface waves were measured for a 3-year period (2004–2007) at a site with mean depth 14 m and mean tidal range 2.1 m. Triaxys surface-following wave buoys reported hourly directional wave energy spectra and wave parameters near the offshore end of the Savannah River Entrance Channel, Georgia, USA. An acoustic Doppler current profiler (ADCP) was located beside the wave buoy for 3 months. Directional and non-directional surface wave energy spectra and the corresponding bulk wave parameters (height, period, and direction) are compared for the two systems. Most parameters derived from the spectra agree closely; the most significant differences were found at the upper and lower frequency measurement limits, where signal-to-noise ratios were lower. The wave buoy consistently reports a small amount of energy below 0.05 Hz that does not appear in the ADCP-derived spectra and does not appear to be related to the mooring system. This leads to larger mean and peak periods reported by the buoy. All directional spectra were computed using the Maximum Entropy Method for both instruments, but the buoy, with spectra derived from six independent time series, provides lower directional resolving power than the ADCP, which utilizes twelve time series. Both systems gave similar results defining mean and peak wave directions, with the primary difference being that the ADCP indicates energy to be more tightly concentrated around the peak direction.  相似文献   

Deformation of monochromatic water wave trains propagating over a submerged obstacle in the presence of uniform currents     

M. Hasanat Zaman  Hiroyoshi Togashi  R. Emile Baddour 《Ocean Engineering》2008,35(8-9):823-833

A nonlinear numerical model based on depth averaged equations and a relevant physical model have been investigated for the deformation of the water wave propagating over a submerged parabolic obstacle in the presence of uniform current. Physical and numerical modeling for wave with both following and opposing currents are done to explore the wave evolutions during passage over the submerged obstacle. A third-order Stokes dispersion relation is utilized in some cases in the computation. Separated flow zone is taken into consideration by two empirical equations obtained from the physical model testing done by the authors. Verification and validation of the numerical model by other published theoretical and experimental data are presented.  相似文献   

Changes in trophic flow structure of Independence Bay (Peru) over an ENSO cycle     

Marc H. Taylor  Matthias Wolff  Jaime Mendo  Carmen Yamashiro 《Progress in Oceanography》2008,79(2-4):336

During the strong warm El Niño (EN) that occurred in 1997/98, Independence Bay (14°S, Peru) showed a ca. 10 °C increase in surface temperatures, higher oxygen concentrations, and clearer water due to decreased phytoplankton concentrations. Under these quasi-tropical conditions, many benthic species suffered (e.g. macroalgae, portunid crabs, and polychaetes) while others benefited (e.g. scallop, sea stars, and sea urchins). The most obvious change was the strong recruitment success and subsequent proliferation of the scallop Argopecten purpuratus, whose biomass increased fiftyfold. To understand these changes, steady-state models of the bay ecosystem trophic structure were constructed and compared for a normal upwelling year (1996) and during an EN (1998), and longer-term dynamics (1996–2003) were explored based on time series of catch and biomass using Ecopath with Ecosim (EwE) software. Model inputs were based on surveys and landings data collected by the Instituto del Mar del Perú (IMARPE). Results indicate that while ecosystem size (total throughput) is reduced by 18% during EN, mainly as a result of decreased total primary production, benthic biomass remains largely unchanged despite considerable shifts in the dominant benthic taxa (e.g. scallops replace polychaetes as secondary consumers). Under normal upwelling conditions, predation by snails and crabs utilize the production of their prey almost completely, resulting in more efficient energy flow to higher trophic levels than occurs during EN. However during EN, the proliferation of the scallop A. purpuratus combined with decreased phytoplankton increased the proportion of directly utilized primary production, while exports and flows to detritus are reduced. The simulations suggest that the main cause for the scallop outburst and for the reduction in crab and macroalgae biomass was a direct temperature effect, whereas other changes are partially explained by trophic interactions. The simulations suggest that bottom-up effects largely control the system.  相似文献   

Laminated sediments from the central Peruvian continental slope: A 500 year record of upwelling system productivity, terrestrial runoff and redox conditions   总被引：1，自引：1，他引：0  

A. Sifeddine  D. Gutirrez  L. Ortlieb  H. Boucher  F. Velazco  D. Field  G. Vargas  M. Boussafir  R. Salvatteci  V. Ferreira  M. García  J. Valds  S. Caquineau  M. Mandeng Yogo  F. Cetin  J. Solis  P. Soler  T. Baumgartner 《Progress in Oceanography》2008,79(2-4):190

Sedimentological studies including X-ray digital analyses, mineralogy, inorganic contents, and organic geochemistry on cores of laminated sediments accumulated in the oxygen minimum zone of the central Peruvian margin reveal variable oceanographic and climate conditions during the last 500 yr. Coherent upcore variations in sedimentological and geochemical markers in box cores taken off Pisco (B0405-6) and Callao (B0405-13) indicate that variability in the climate proxies examined has regional significance. Most noteworthy is a large shift in proxies at 1820 AD, as determined by ²¹⁰Pb and ¹⁴C radiometric dating. This shift is characterized by an increase in total organic carbon (TOC) in parallel with an abrupt increase in the enrichment factor for molybdenum Mo indicating a regional intensification of redox conditions, at least at the sediment water interface. In addition there was lower terrestrial input of quartz, feldspar and clays to the margin. Based on these results, we interpret that during several centuries prior to 1820, which corresponds to the little ice age (LIA), the northern Humboldt current region was less productive and experienced higher terrestrial input related to more humid conditions on the continent. These conditions were probably caused by a southward displacement of the inter-tropical convergence zone and the subtropical high pressure cell during the LIA. Since 1870, increases in TOC and terrigenous mineral fluxes suggest an increase of wind-driven upwelling and higher productivity. These conditions continued to intensify during the late 20th century, as shown by instrumental records of wind forcing.  相似文献   

东大港水道流速垂线分布探讨   总被引：2，自引：0，他引：2  

吴德安  崔效松  童朝锋  张忍顺 《海洋科学》2008,32(3):49-54

对辐射沙洲海域东大港水道4号站位连续2个潮次的流速测量资料进行了分析、研究,拟合给出了流速垂线分布关系,并根据实际测量资料率定了该站位各时刻6个水层的浑水水流的尾流函数项表达式,这些表达式表明浑水水流的尾流函数项是相对深度和摩阻速度的函数。  相似文献   

Surface current and vertical thermal structure on the continental slope in Tosa Bay     

Hiroshi Kuroda  Manabu Shimizu  Yuuichi Hirota  Daisuke Ambe  Hideki Akiyama 《Journal of Oceanography》2008,64(1):81-91

In order to specify a vertical thermal structure related to surface current variation on the continental slope in Tosa Bay, Japan, we analyzed monthly regular hydrographic measurements in the years 1991–2004. Subsurface temperature below 200 m on the slope was found to vary synchronously with the vertical displacement of the main thermocline around 200 m. It is shown that the vertical-averaged temperature below 200 m is significantly correlated with an along-isobath/southwestward surface current velocity on the slope. This correlation indicates that when a strong (weak) southwestward surface current is observed, temperature below 200 m decreases (increases) simultaneously, that is, isotherms below the 200 m are displaced upward (downward) together with the main thermocline. Moreover, when the strong southwestward flow is detected, across-isobath isotherms around 200 m slope upward toward the offshore direction. Furthermore, it is suggested that as the Kuroshio axis moves offshore south of the bay, the southwestward flow tends to be weakened by the combined effect of other Kuroshio parameters such as transport and stream width as well as the Kuroshio axis position. As a result, it is inferred that the correlation between the surface current and subsurface temperature can be interpreted in terms of the formation and decay of an anticlockwise circulation interacting with a cold eddy.  相似文献   

Tidal modification and its effect on sluice-gate outflow after completion of the Saemangeum dike,South Korea     

Seok Lee  Heung-Jae Lie  Kyu-Min Song  Cheol-Ho Cho  Eun-Pyo Lim 《Journal of Oceanography》2008,64(5):763-776

This study examined tidal modification and change in tidal currents caused by the construction of the Saemangeum dike, based on field observations and a numerical model. The Saemangeum dike was completed in April 2006, enclosing an estuarine area along the mid-western coast of South Korea. After closure of the dike, the tidal range outside the dike decreased slightly but significantly, while the inside tidal range decreased drastically. The numerical model results show that the dike construction has influenced tidal energy propagation and the tidal system in the Yellow Sea. The tidal current speed near the dike decreased abruptly following closure of the dike, except in front of the sluice gates. Since completion of the dike, outflow water discharged from the sluice gates has longer residence times due to the weakened tidal current; the change in the tidal current field has also caused greater northward expansion of outflow water. The sluice gates release fresher water, which spreads over the sea surface mainly by inertial momentum near the gate; this water is then gradually mixed with sea water farther from the gate. The less saline, possibly more contaminated outflow impacts the marine environment near the Saemangeum dike. Controlling the discharge and gate-opening timing can partially mitigate these impacts on the marine environment.  相似文献