固定式海洋平台利用TLD的减震研究   总被引：7，自引：0，他引：7  

李宏男  马百存 《海洋工程》1996,(3)

本文研究固定式海洋平台利用调谐液体阻尼器（ＴｕｎｅｄＬｉｑｕｉｄＤａｍｐｅｒ，简称ＴＬＤ）减小地震反应的方法。首先探讨了调谐频率比、激磁频率比对减震效果的影响，在此基础上建立了ＴＬＤ——平台系统的力学模型和运动方程，通过数值计算验证了该方法的有效性  相似文献   

Benthic mineralization rates at two locations in the southern North Sea     

Ronald Osinga  Arjen J. Kop  Gerard C. A. Duineveld  Rudolf A. Prins  Fleur C. Van Duyl 《Journal of Sea Research》1996,36(3-4)

Benthic oxygen uptake, sulphate reduction and benthic bacterial production were measured at two contrasting locations in the southern North Sea: the shallow and turbulent Broad Fourteens area in the Southern Bight, and the deeper Oyster Grounds, a deposition area, where thermohaline stratification occurs during summer. Oxygen uptake and sulphate reduction showed a clear seasonal pattern in the Broad Fourteens area, indicating a supply of carbon to the benthic system that is closely related to the standing stock of carbon in the water column. This close benthic-pelagic coupling is probably due to the influence of the tide in this part of the North Sea, which keeps the water column permanently mixed. At the Oyster Grounds, no seasonal pattern was observed. Peaks in oxygen uptake and sulphate reduction were found in winter. Irregularly occurring events, such as storms and fishery-related activities, are likely to affect the benthic mineralization patterns in this area. Annual benthic carbon mineralization rates estimated from oxygen uptake rates were 44 gC·m⁻² at the Broad Fourteens, and 131 gC·m⁻² at the Oyster Grounds, of which 26 and 28%, respectively, could be attributed to sulphate reduction (assuming an annual sulphide reoxidation rate of 100%). Although sulphate reduction rates in the southern North Sea are higher than previously suggested, aerobic respiration is the most important pathway for benthic carbon mineralization at the stations visited. Production rates of benthic bacterial carbon measured with labelled leucine were much higher than carbon mineralization rates based on oxygen uptake or sulphate reduction. This may either imply a very high bacterial carbon conversion efficiency, or point to shortcomings in the accuracy of the techniques. A critical evaluation of the techniques is recommended.  相似文献   

江苏大丰潮滩潮流边界层特征研究   总被引：7，自引：0，他引：7  

李占海  高抒  陈沈良 《海洋工程》2007,25(3):53-60

2003年7月中小潮期间使用MIDAS-400用户化数据采集系统在江苏大丰潮滩上进行了垂向多层位同步的流速和悬沙浓度观测。根据观测资料研究了潮流作用下的潮滩底部边界层过程,结果表明,观测地点的潮汐不对称现象十分明显,落潮流速、历时和输水输沙量皆明显大于涨潮;在潮周期内的多数时间里流速剖面符合对数分布,但在风力较强、水流快速增加和流速缓慢的情况下,流速剖面常偏离对数分布;悬沙颗粒垂向混合均匀,悬沙浓度剖面符合Rouse公式;落潮时的底部切应力和摩阻流速明显大于涨潮,摩阻流速与各水层流速通常有较好的线性关系;滩面糙度主要与沙纹形态和推移质运动强度有关,它与摩阻流速存在密切关系;悬沙浓度具有明显的减阻效应,受其影响,摩阻流速和底部切应力分别减小了28%~41%和40%~62%。  相似文献   

A Model for the Calculation of Velocity Reduction Behind A Plane Fishing Net     

桂福坤李玉成  赵云鹏董国海 《中国海洋工程》2006,20(4):615-622

1 .IntroductionOpen oceanaquacultureis becominga newfisheriesindustryasthe human demandfor seafoodin-creases .Consideringthe requirement of environmental protection,thelackof suitable shelteredsitesisforcingfishfarmers to move to more exposed offshore loc…  相似文献   

E1 Nio phenomenon in simple ocean data assimilation data     

GUI Maochang  *  WU Lingjuan  . Institute of Oceanology  Chinese Academy of Sciences  Qingdao  China. Laboratory of Numerical Modeling for Atmospheric Sciences  Geophysical Fluid Dynamics  Institute of Atmospheric Physics  Chine-se Academy of Sciences  Beijing  China. Graduate School  Chinese Academy of Sciences  Beijing  China 《海洋学报(英文版)》2005,(4)

1 IntroductionIt is well known that interaction between the trop-ical ocean and atmosphere produces the largest inter-annual climate signal, El Nino-Southern Oscillation(ENSO). In past decades many efforts have been madein understanding and predicting ENSO: such as the hy-pothesis of Bjerknes (1969) that ENSO arises as aself-sustained cycle in which SSTA in the Pacific O-cean causes the trade winds to strengthen or slackenand that this in turn drives the ocean circulation changesthat …  相似文献   

The Agulhas Ridge, South Atlantic: The Peculiar Structure of a Fracture Zone     

Gabriele Uenzelmann-Neben  Karsten Gohl 《Marine Geophysical Researches》2004,25(3-4):305-319

The Agulhas Ridge is a prominent topographic feature that parallels the Agulhas-Falkland Fracture Zone (AFFZ). Seismic reflection and wide angle/refraction data have led to the classification of this feature as a transverse ridge. Changes in spreading rate and direction associated with ridge jumps, combined with asymmetric spreading within the Agulhas Basin, modified the stress field across the fracture zone. Moreover, passing the Agulhas Ridge’s location between 80 and 69 Ma, the Bouvet and Shona Hotspots may have supplied excess material to this part of the AFFZ thus altering the ridge’s structure. The low crustal velocities and overthickened crust of the northern Agulhas Ridge segment indicate a possible continental affinity that suggests it may be formed by a small continental sliver, which was severed off the Maurice Ewing Bank during the opening of the South Atlantic. In early Oligocene times the Agulhas Ridge was tectono-magmatically reactivated, as documented by the presence of basement highs disturbing and disrupting the sedimentary column in the Cape Basin. We consider the Discovery Hotspot, which distributes plume material southwards across the AAFZ, as a source for the magmatic material.  相似文献   

新型波浪采集系统平台设计     

刘世萱  王孝坤  牟长青 《海洋技术学报》2004,23(2):90-92

主要介绍了新型波浪采集系统的设计思想与主要参数，采集、存储、运算和电源控制部分的结构与组成，以及各部分的特点和关键技术。  相似文献   

多波束数据的海底数字地形模型构建   总被引：11，自引：0，他引：11  

高金耀  金翔龙  吴自银 《海洋通报》2003,22(1):30-38

提出大批量多格式原始多波束数据的DTM构建方法，以满足大区域、大比例尺海底地形制图的需要。在多种格式原始多波束数据接口和系统内部标准数据结构的基础上，通过对数据文件、数据种类和数据运算量的有效组织管理，实施边读入、边权重配赋的网格插值，分析了高斯、指数和距离平方反比权重函数的适用性，及最小值、最大值和平均值的实用性。在权重配赋网格插值基础上，提出分形fBM和张力样条配合使用的方程式插值方法，保证DTM数据的有效外延和地形分辨。整套算法效率高，并能有效保证DTM的精度，对存储在外部介质的数据遍历一次即可完成网格插值。  相似文献   

Geophysical Evidence of a Relict Oceanic Crust in the Southwestern Scotia Sea     

Lodolo  Emanuele  Coren  Franco  Schreider  Anatoly A.  Ceccone  Giulio 《Marine Geophysical Researches》1997,19(5):439-450

The southwestern part of the Scotia Sea, at the corner of the Shackleton Fracture Zone with the South Scotia Ridge has been investigated, combining marine magnetic profiles, multichannel seismic reflection data, and satellite-derived gravity anomaly data. From the integrated analysis of data, we identified the presence of the oldest part of the crust in this sector, which tentative age is older than anomaly C10 (28.7 Ma). The area is surrounded by structural features clearly imaged by seismic data, which correspond to gravity lows in the satellite-derived map, and presents a rhomboid-shaped geometry. Along its southern boundary, structural features related to convergence and possible incipient subduction beneath the continental South Scotia Ridge have been evidenced from the seismic profile. We interpret this area, now located at the edge of the south-western Scotia Sea, as a relict of ocean-like crust formed during an earlier, possibly diffuse and disorganized episode of spreading at the first onset of the Drake Passage opening. The successive episode of organized seafloor spreading responsible for the opening of the Drake Passage that definitively separated southern South America from the Antarctic Peninsula, instigated ridge-push forces that can account for the subduction-related structures found along the western part of the South Scotia Ridge. This seafloor accretion phase occurred from 27 to about 10 Ma, when spreading stopped in the western Scotia Sea Ridge, as resulted from the identification of the marine magnetic anomalies.  相似文献   

周期浅析     

战淑芸  杨淑瑞 《海洋预报》1992,9(4):47-51

本文分析了滑动平均的数据处理方法对周期分析结果产生的影响。提出了过程变量同号积分的数据处理方法,并对亚洲西风指数序列进行了试验分析。分析结果表明,周期的长短与振幅的大小有密切关系,亚洲逐日西风指数的周期振荡具有明显的季节特征。  相似文献