浅海浮力平流效应     

杨殿荣  徐静琦  魏皓 《中国海洋大学学报(自然科学版)》1994,(4)

浮力平流直接影响着海洋内部的湍流混合过程，制约着海洋热盐结构的形成和变化。这一过程在浅海，尤其在象渤黄海那样具有较强浮力平流的中国大陆沿岸带海区，是十分重要的。本文主要讨论浅海浮力平流对温跃层和海洋锋的影响，从理论上导出在浮力平流效应作用下期混合锋的公式，并以南黄海为例进行了计算，计算结果是令人满意的。  相似文献   

Current and Turbidity Variations in the Western Part of Suo-Nada, the Seto Inland Sea, Japan: A Hypothesis on the Oxygen-Deficient Water Mass Formation     

Tomoharu Senjyu  Hidekazu Yasuda  Shigehiko Sugihara  Masato Kamizono 《Journal of Oceanography》2001,57(1):15-27

A hydrographic survey and a 25-hour stationary observation were carried out in the western part of Suo-Nada in the summer of 1998 to elucidate the formation mechanism of the oxygen-deficient water mass. A steep thermocline and halocline separated the upper layer water from the bottom water over the observational area except for near the Kanmon Strait. The bottom water, in comparison with the upper layer water, indicated lower temperature, higher salinity, lower dissolved oxygen, higher turbidity, and higher chlorophyll a. Turbidity in the upper layer water changed with semi-diurnal period while the bottom water turbidity showed a quarter-diurnal variation, though the M₂ tidal current prevailed in both waters. From the turbidity distribution and the current variation, it is revealed that the turbidity in the upper layer water is controlled by the advection due to the M₂ tidal current. On the other hand, the quarter-diurnal variation in the bottom water turbidity is caused by the resuspension of bottom sediments due to the M₂ tidal current. The steep thermocline and halocline were maintained throughout the observation period in spite of the rather strong tidal currents. This implies an active intrusion of the low temperature and high salinity water from the east to the bottom of Suo-Nada. Based on the observational results, a hypothesis on the oxygen-deficient water mass formation was proposed; the periodical turbidity variation in the bottom water quickly modifies the oxygen-rich water in the east to the oxygen-deficient bottom water in Suo-Nada in a course of circulation.  相似文献   

Species richness and environmental conditions of fish along the Norwegian Skagerrak coast     

Lekve  Kyrre; Stenseth  Nils Chr.; Gjosaeter  Jakob; Doledec  Sylvain 《ICES Journal of Marine Science》2002,59(4):757-769

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A dynamic study of explosive cyclogeneses developments over the ocean     

张永刚  孙成志  吕美仲  欧阳子济 《海洋预报》2001,18(Z1)

1 IwrRODUcrIONIt is necessary to understand disastrous weather systems as the activities of exploitingand uti1izing marine resources, especialIy for the needs of navigation and oil-gas prospecting.Typhoon is the most frequent and dangerous disastrous weather system in summer-autumnseason in the Nolthwest Pacific Ocean. The explosive cyclogenesis developing quickly overocean is the most terrible weather system in winteL The explosive cycnogenesis grows fastwith high intensity of violent wi…  相似文献   

Modelling the effect of a slope-water intrusion on advection of fish larvae in May 1995 on Georges Bank   总被引：1，自引：0，他引：1  

Manning  J. P.; Lough  R. G.; Naimie  C. E.; Churchill  J. H. 《ICES Journal of Marine Science》2001,58(5):985-993

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Stage-specific habitats of Calanus finmarchicus and Calanus helgolandicus in a stratified northern Norwegian fjord     

Skreslet  S.; Olsen  K.; Mohus  A.; Tande  K. S. 《ICES Journal of Marine Science》2000,57(6):1656-1663

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Modelling the population dynamics of Calanus in the Fair Isle current of northern Scotland     

M. Heath  W. Robertson  J. Mardaljevic  W. S. G. Gurney 《Journal of Sea Research》1997,38(3-4)

The population dynamics of a marine zooplankton species in the Fair Isle Current off northern Scotland have been investigated by modelling and field study. An age- and weight-structured model of a population of the copepods Calanus finmarchicus and Calanus helgolandicus was embedded in a biomass based ecosystem model comprising nutrients, phytoplankton, and other non-Calanus zooplankton. The model was configured to represent a Lagrangian water column drifting in the Fair Isle Current off the north of Scotland during June 1988, with physical characteristics derived from the results of a three-dimensional hydrodynamic model of the northwest European shelf. The time-series results from the model were compared to data from a semi-synoptic field study by assuming the system to be short-term steady state and transposing the spatially resolved field observations into pseudo-time series along the modelled column drift track. The hydrodynamic model correctly reproduced the general physical characteristics of the system which were destratification of an initially stratified water column as a result of advection through a tidally energetic mixing zone, and subsequent re-establishment of stratification with distance downstream. The biological components of the model were broadly successful at reproducing the main features of the phytoplankton biomass response to the physical processes. The field data indicated that, despite the short-term changes in phytoplankton abundance along the drift track, the stage composition and biomass of the Calanus population was relatively stable. However, the model revealed that the main diagnostic features of the response were at the individual level, reflected in the weight at age distribution and reproductive output. The study highlights the difficulty of obtaining adequate data for testing complex models of zooplankton responses to short-term spatio-temporal variations in physical forcing.  相似文献   

赤道太平洋温度纬向对流距平分析及其与El Ni(n)o/La Ni(n)a的关系     

蔡怡  余宙文 《海洋预报》2004,21(1)

本文用最近 20 年赤道太平洋温度、流场资料,诊断了绝热不可压缩热平衡方程中纬向对流项,并且利用 EOF 分析方法,讨论了纬向对流距平变化及其与 El Nino/La Nina 的关系。分析发现:赤道太平洋温度纬向对流距平 EOF 分析第一模态反映了在经向的振荡,第二模态反映了在纬向的振动,它们都与 El Nino/LaNina 有密切的联系。这两个模态占了总量的 70%左右。纬向温度对流距平在 3°S~3°N、3°S 以南和 3°N 以北分为正负相间的三个不同的区域,当 3°S 以南和 3°N 以北的区域温度纬向对流正/负距平沿着斜温层向西太平洋移动时,赤道区域的温度纬向对流负/正距平则穿越斜温层向东太平洋移动,形成以赤道为对称的南北两个回路。对应赤道,在 3°S 以南和 3°N 以北区域的纬向温度对流距平并不是对称的,它们在位相、中心强度和中心强度位置上都是不同的,其中 3°N 以北与赤道区域形成一个比较明显的回路,而赤道以南的回路就不是那么明显。在赤道西太平洋暖池,温度的纬向对流有很大的贡献。在 El Nino 发生前一年,赤道西太平洋暖池,主要暖的对流发生在赤道和其以南地区。  相似文献   

Case Comparing Study of Downstream Circulation Development during Typhoon Extratropical Transition     

Chen Hua  Huo Ye 《地球科学进展》2016,31(4):409-421

The interaction between extratropical transition process and the mid-latitude jet system stimulates the downstream development. In this paper, three typhoon cases were selected to study their downstream development mechanism through the analysis of the eddy kinetic energy budget and the idealized simulations. The results of Chen’s work to the Pacific region were examined. The results were consistent with the results of Chen’s Atlantic hurricane Case. ET downstream at the upper levels generated first eddies, and the disturbances triggered the low level eddy development. Then the upper and the lower coupled and formed a deep cyclone system throughout the whole troposphere. The ageostrophic geopotential flux promoted the formation and development of the downstream ridge from the typhoon. Vertical ageostrophic geopotential flux transferred energy from upper downward that convergence happened in lower, which stimulated the lower-level cyclone development. Simulation results showed that, in the process of ET, TC outflow transported low potential vorticity to mid-latitude jet, which enhanced the PV gradient and the baroclinic. Then, it is inspired the Rossby wave in the jet and propagated downstream. The formation of downstream ridge-trough couple and development of the further wave was the spread to the downstream through the Rossby wave.  相似文献   

基于单颗粒受力的均匀推移质颗粒对流和扩散特征          下载免费PDF全文

范念念  聂锐华  杨克君  刘兴年  陈日东 《水科学进展》2016,27(2):249-255

为揭示均匀推移质颗粒对流和扩散特性的控制因素,建立了间歇郎之万方程模型。该模型可在单颗粒尺度充分考虑颗粒的受力特性,模拟颗粒随机、间歇运动过程。通过该模型引入不同的停时分布,对模拟的大量单颗粒运动过程进行统计,从而研究均匀颗粒在大的时空尺度上的对流和扩散特征。结果表明,对于均匀颗粒,受颗粒速度分布的窄尾性限制,即便单步步长是长尾分布,也不一定产生超扩散,扩散特性由停时分布的尾部特征决定,不同分布的停时可导致欠扩散、超扩散和正常扩散。进一步与已有的、复杂程度不同的随机模型进行对比,表明忽略单步时间将影响颗粒的扩散(二阶)特性,但不影响颗粒的对流(一阶)特性,类似地可以推广到更普遍规律,即所研究随机发生的统计矩阶数越高,需要的模型越复杂。  相似文献