A thermal centroid or a mass centroid?     

Mingqiang Fang 《Journal of Oceanography》2006,62(5):759-766

This study reveals the physical backgrounds of the geometric centroid and the thermal centroid of the Western Pacific Warm Pool (WPWP) and points out their differences. The geometric centroid (actually a very close approximation to the mass centroid) anomaly of the surface WPWP correlates more closely with the Niño-3 region sea surface temperature anomaly (Niño-3 SSTA, an important indicator of El Niño/La Niña events) than the surface thermal centroid. Taking the WPWP depth (or heat storage) into account, the “real” mass or thermal centroid of the WPWP might correlate better with the El Niño/Southern Oscillation (ENSO) signals.  相似文献   

长期非平稳荷载调谐质量减振阻尼器优化设计     

李华军  陆建辉  嵇春艳 《中国海洋大学学报(自然科学版)》2002,32(3):489-494

研究外荷载为长期非平稳随机过程。考虑长期荷载的特性 ,采用 1个概率谱密度函数来反映长期非平稳随机荷载及其特征 ;概率谱密度函数是基于大量的一般谱密度函数的统计特性获得。以延长结构的抗疲劳使用寿命为目标函数 ,提出了调谐质量减振阻尼器的优化设计方法 ,这在实际工程中有着极为广阔的应用前景。本文旨在从理论上发展长期非平稳随机荷载作用下调谐质量减振阻尼器的优化设计方法 ;文中采用长期波浪实测数据 ,给出了 1个数值算例说明整个设计过程。  相似文献   

烟威及石岛近海春季水团分析     

郑东  张瑞安 《中国海洋大学学报(自然科学版)》1989,(Z1)

本文使用1960—1980年春季的水文资料,以温度和盐度作为主要指标,根据聚类分析逼近温盐图解,结合对该海域地理环境特征的分析,对烟台、威海及石岛近海春季的水团结构演变及其和渔场、渔期的关系进行综合分析。结果表明,北黄海及青岛外海的冷水团,以及黄海暖水团的强度与位置的变动,对春季渔期的早迟以及渔场位置的变动,都有很大的影响。  相似文献   

Determination of cadmium(II), copper(II), manganese(II) and nickel(II) species in Antarctic seawater with complexing resins   总被引：1，自引：0，他引：1  

Raffaela Biesuz  Giancarla Alberti  Girolamo D'Agostino  Emanuele Magi  Maria Pesavento 《Marine Chemistry》2006,101(3-4):180-189

The strong species of cadmium(II), copper(II), manganese(II) and nickel(II) in an Antarctic seawater sample are investigated by a method based on the sorption of metal ions on complexing resins. The resins compete with the ligands present in the sample to combine with the metal ions. Two resins with different adsorbing strengths were used. Very stable metal complexes were investigated with the strong sorbent Chelex 100 and weaker species with the less strong resin, Amberlite CG-50. Strong species were detected for three of the considered metal ions, but not for Mn(II). Cu(II) is completely linked to species with a side reaction coefficient as high as log α_M(I) = 11.6 at pH = 7.3. The ligand concentration was found to be similar to that of the metal ion, and the conditional stability constant was around 10²⁰ M^− 1. In the considered sample, only a fraction of the metal ions Cd(II) and Ni(II) is bound to the strong ligands, with side reaction coefficients equal to log α_M(I) = 5.5 and 6.5 at pH = 7.3 for Cd(II) and Ni(II), respectively. These findings were confirmed by the test with the weaker sorbent Amberlite CG-50. It can be calculated from the sorption equilibria that neither Mn(II) nor Ni(II) is adsorbed on Amberlite CG-50 under the considered conditions and, in fact, only a negligible fraction of Mn(II) and Ni(II) was adsorbed. A noticeable fraction of Cd(II) was adsorbed on Amberlite CG-50, meaning that cadmium(II) is partially linked to weak ligands, possibly chloride, while no copper(II) was adsorbed on this resin, confirming that copper(II) is only combined in strong species. These results are similar, but not identical, to those obtained for other seawater samples examined in previous investigations.  相似文献   

应用Argo资料分析西北太平洋冬、夏季水团   总被引：1，自引：0，他引：1  

孙朝辉  刘增宏  童明荣  朱伯康  许建平 《海洋学研究》2007,25(3):1-13

应用Argo剖面浮标观测的温、盐度资料,分析了西北太平洋海域冬、夏季的温、盐度分布、水团结构及其分布。首先采用T-S点聚图法分析了该海域水团分布的基本情况,由点聚分析结果可知,该海域至少存在6种以上水团;再用模糊聚类软化法对水团作进一步划分,分别计算了该海域6至11类水团的F和△F值,结果表明,冬、夏季的△F值都以划分为8类时为最大,这与大洋水团的稳定性是一致的,因此,该海域冬、夏季水团以划分为8类最佳,它们分别是北太平洋热带表层水、北太平洋次表层水、北太平洋中层水、北太平洋副热带模态水、北太平洋深层水和赤道表层水,以及南太平洋次表层水和南太平洋中层水。  相似文献   

Modelling linear wave transformation induced by dissipative structures—Random waves     

R. Silva  M.A. Losada  P. Salles 《Ocean Engineering》2006,33(16):2174-2194

The relevant theory is presented and numerical results are compared with the analytical solution for the interaction of non-breaking waves with an array of vertical porous circular cylinders on a horizontal bed. The extension to the cases of unidirectional and multidirectional waves is obtained by means of a transfer function. The influence of the mechanical properties of porous structures and wave irregularity on wave transformation is analysed. Results for unidirectional and multidirectional wave spectra are compared to those obtained for regular waves. The model presented reproduces well the analytical results and provides a tool for analysing several engineering problems.  相似文献   

一种污水排海的近远区计算与控制方法──以大亚湾水容量计算及污水排海为例     

韩保新  彭海君  曾小清  胡康萍  吕先林 《热带海洋学报》1996,(4)

针对点容量计算中混合区限制的要求，采用了动量积分法、经验公式法和有限差分法，分别对污水排放后可能引起的近区、过渡区和远区的污水浓度变化进行了模拟预测，并就一定的限制性条件对容量点近区、高浓度混合区及容量点远区影响范围进行了分析。在大亚湾水容量计算及污水排海规划中的应用表明，该法具有计算机时较省、精度相对较高等优点。  相似文献   

An experimental method for determining the frequency-dependent added mass and added mass moment of inertia for a floating body in heave and pitch motions     

Jong-Shyong Wu  Mang Hsieh   《Ocean Engineering》2001,28(4):528

Most of the existing relevant materials have been obtained from experiments, in which evaluating the added mass at the resonant frequency corresponding to the peak of a frequency-response curve obtained from the “forced” vibration analysis is the most popular technique. In this paper, a simple experimental method was presented where the “free” vibration responses instead of the “forced” ones were used to determine the values of m_ah and I_ap. The main part of the experimental system is composed of a floating body (model) and a spring–shaft shaker. The “free” vibration of this main part was induced by imposing on it an initial displacement (and/or an initial velocity), and from the time histories of displacements information such as the “damped” natural frequencies, damping ratios, sectional added mass coefficients (C_V and C_P) were obtained. Since the displacements of the spring–shaft shaker are “translational” and those of the floating body due to pitch motions are “angular”, a technique for the transformation between the associated parameters of the two components of the main part was presented.  相似文献   

柴达木盆地新构造运动主要特征与成因机制   总被引：10，自引：0，他引：10  

杨明慧 《海洋地质与第四纪地质》1997,17(3):71-78

研究表明，在壳幔结构、地球物理背景、沉积物结构、多层关地幔和构造样式等方面，达木盆地与中国东部新生代裂谷类伸展盆地具有可比性，应该归属 展性盆 。盆地伸展和收缩作用相间进行，伸展起因于地幔底辟；而收缩受两人因素影响；（１）盆地伸展作用受相邻造山带反作用诱导的挤压应力；（２）板块碰撞传递的远程板内应力。在此基础邮新的构造期达木盆地演化的“双层模式”，即地幔上隆－地壳伸展；被动挤压＋板内应力－地壳收缩  相似文献   

MM5数值预报产品在舟山海域风力分区预报中的释用   总被引：1，自引：0，他引：1  

黄辉  陈淑琴 《海洋预报》2006,23(2):67-71

本文阐述了舟山海域地理气候特征及开展舟山海域风力分区预报的重要性,详细介绍了利用海岛测风站资料研究的MM5数值预报产品在舟山海域风力分区预报中的释用技术,实践证明该释用技术能为风力分区预报提供重要的技术支撑,并为研究同类数值预报产品释用技术提供重要的参考依据。  相似文献