渤海垂直湍流混合强度季节变化的数值模拟   总被引：4，自引：1，他引：4  

赵亮  魏皓 《中国海洋大学学报(自然科学版)》2001,31(3):313-318

渤海为极浅陆架海 ,其中湍流耗散作用显著。将三维斜压陆架海模式 HAMSOM应用于渤海 ,以渤海周边台站每天 4次的常规气象资料作为风和热驱动 ,渤海海峡开边界以 5个主要分潮调和常数计算水位强迫 ,计算了渤海 1982年水文要素和流场变化 ,并用模式以湍的局地平衡理论封闭计算出垂直湍流粘性的时空分布。结果表明 :渤海湍流混合冬强夏弱 ,变化幅度较大 ( 10～ 2 0 0 cm2 / s) ,这是风搅拌和潮混合的湍流输入在密度层化调整下的结果 ;风的作用在冬季强于潮的作用 ,而底层则由潮混合控制呈现半月周期 ;渤海湍粘性系数的空间分布十分复杂 ,这是在渤海地形和岸形轮廓限制下 ,由一定大气条件驱动的流场和密度场导致的湍流混合强度不同所致  相似文献   

长江中下游6月份降水的一个预报指标     

赵永平  陈永利 《海洋科学》1995,19(1):39-42

根据１９６３－１９９２年嵊山海洋站２月海气感热输送和２２ａ太阳磁周期与降水的关系，提出了一个长江中下游６月降水的综合预报指标，用此指标，对１９９３年６月长江中下游降水进行回报，结果与实况一致。  相似文献   

南疆博斯腾湖近12.OkaB.P.以来古气候与古水文状况的变化   总被引：6，自引：0，他引：6  

钟巍  舒强 《海洋与湖沼》2001,32(2):213-219

对南疆博斯腾湖湖相沉积物多手段的综合研究，揭示了近12.0kaB.P.以来古气候与古水文状况的变化过程与特征。结果表明，其气候的演化特征具有明显的西风型环境演变特征。研究还发现气候于12.0ka、10.0ka、4.0ka和1.5kaB.P.存在显著的阶梯式增暖变干特征，其中暖峰主要出现于11.5—11.0ka、9.4ka、7.5—7.0ka、6.5—6.0ka、3.0ka和2.0kaB.P.，气候特征以干暖为主，湖泊水文特征总体表现为盐度增加、水位下降、湖面缩小；而冷峰主要出现于11.0—10.0ka、8.8ka、5.0—4.5ka、3.3ka和1.5kaB.P.，此时湖泊膨胀淡化，湖面上升。在7.0—5.0kaB.P.期间出现的相对暖湿环境特征可能是全新世大暖期最盛期暖湿气候特征的反映，可能与此时西南夏季风势力增强有关，湖泊水文状况明显变好。  相似文献   

关于“包装产品的计量标准型一次抽检方案”的确定     

陈峥  赵维谦  李晓川 《中国海洋大学学报(自然科学版)》1989,(4)

本文给出了“包装产品的计量标准型一次抽检方案”,并通过一个实例说明本方案比一般《计量标准型一次抽检方案》更为优越。  相似文献   

胶南构造混杂岩带中糜棱岩的显微形变特征与古构造环境——来自榴辉岩围岩的构造信息     

赵广涛  张保民  韩宗珠 《中国海洋大学学报(自然科学版)》1992,(4)

以胶南构造混杂岩带中榴辉岩的围岩——套程度不同的糜棱岩化岩石为研究对象,重点研究了其显微形变的结构特征及环境意义、石英组构特征及动力学信息,并讨论其形成的古构造环境和构造机制。  相似文献   

Dynamics and control of a towed underwater vehicle system, part I: model development     

B. Buckham  M. Nahon  M. Seto  X. Zhao  C. Lambert 《Ocean Engineering》2003,30(4):82-470

Autonomous vehicles are being developed to replace the conventional, manned surface vehicles that tow mine hunting towed platforms. While a wide body of work exists that describes numerical models of towed systems, they usually include relatively simple models of the towed bodies and neglect the dynamics of the towing vehicle. For systems in which the mass of the towing vehicle is comparable to that of the towed vehicle, it becomes important to consider the dynamics of both vehicles. In this work, we describe the development of a numerical model that accurately captures the dynamics of these new mine hunting systems. We use a lumped mass approximation for the towcable and couple this model to non-linear numerical models of an autonomous surface vehicle and an actively controlled towfish. Within the dynamics models of the two vehicles, we include non-linear controllers to allow accurate maneuvering of the towed system.  相似文献   

渤海南部表层沉积的相特征   总被引：1，自引：0，他引：1  

王琦  赵其渊  杨作升  周莉  沈渭铨  周伟  李平 《中国海洋大学学报(自然科学版)》1989,(1)

通过海上调查及实验室分析,查明渤海南部表层沉积物在结构类型、矿物组合、生物组分及沉积构造等相特征方面具有明显的分区性。渤海南部存在五种沉积相:黄河水下三角洲相、陆架盆地相、海湾相、潮流浅滩相及古滨岸相。黄河水下三角洲相从河口延至水深15—20米处,沉积速率很高,沉积物富含碎屑云母及CaCo_3。陆架盆地相的沉积为粉砂质粘土,具有生物扰动构造。  相似文献   

A method for detecting the breaking of wind-generated waves in deep water   总被引：1，自引：0，他引：1  

Xu Delun  Lou Shunli  Zhao Meng  Liu Wentong 《海洋学报(英文版)》1991,10(2):281-285

The breaking of wind-generated waves is an important phenomenon in the ocean, having close relation to many aspects of the ocean, such as air-sea interaction, ocean wave dynamics, oceanic remote sensing and ocean engineering. The first problem encountered in both its theoretical study and practical measurement is how to detect the breaking of waves.  相似文献   

Cheniers in China: An overview   总被引：6，自引：0，他引：6  

Xitao Zhao 《Marine Geology》1989,90(4):311-320

In various regions along the east and southeast coast of China and on the outer shelf of the East China Sea, series of cheniers have been found and studied. Their geomorphological and sedimentological features have been described and the main conditions for their formation established.

The development of cheniers in China can be divided into three periods: 24,000-15,000 yrs B.P., 7000-5000 yrs B.P. and 5000 yrs B.P. onwards. These periods have been based on ¹⁴C datings of 80 shell samples. The chenier groups of the three periods are distributed throughout various geomorphological locations.

Using the geomorphological locations of the cheniers in combination with their age of formation, the palaeopositions of the Chinese coastline in the various periods since 24,000 yrs B.P. are described. The history of the position of the east coast of China, including the features attesting to sealevel changes during this era, is briefly discussed.  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