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   

HY1200声速剖面仪计算测深仪声速改正数方法     

关致和  赵先龙  邵海涛  王莉娜  阮锐  于政 《海洋测绘》2006,26(1):66-67,74

介绍了HY1200声速剖面仪平均声速的定义及应用,以及用平均声速进行测深仪声速改正数的方法和公式。  相似文献   

莱州湾地区郯庐断裂带的构造特征及其新生代演化   总被引：22，自引：0，他引：22  

吴时国  余朝华  邹东波  张海英 《海洋地质与第四纪地质》2006,26(6):101-110

郯庐断裂带中段分东西两支从莱州湾进入渤海,在莱州湾地区的构造特征与演化历史一直鲜为人知。通过对横穿研究区的两条地震测线的解释和分析,揭示了该区郯庐断裂带中段在研究区的构造差异,研究表明郯庐断裂带东西两支在该研究区表现出不同的断裂性质,西支断裂表现为正断层,东支断裂表现为走滑断层。郯庐断裂是本研究区的主控断裂,通过对本地区地层形态及其组合、断层的剖面形态和空间展布规律的深入研究,揭示了郯庐断裂带在莱州湾地区新生代以来的构造演化历史:古新世—始新世的伸展阶段、渐新世—中新世早期的挤压和右行走滑阶段、中新世中晚期至今的稳定发展阶段,这几个不同时期的演化阶段主要受太平洋板块运动的方向和速度变化的控制。  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   

Imaging of Buried Archaeological Materials: The Reflection Properties of Archaeological Wood   总被引：1，自引：0，他引：1  

Stephanie H.L. Arnott  Justin K. Dix  Angus I. Best  David J. Gregory 《Marine Geophysical Researches》2005,26(2-4):135-144

Effective marine archaeological site management demands detailed information on not only the spatial distribution of artefacts but also the degradation state of the materials present. Although sonar methods have frequently been used in an attempt to detect buried wooden shipwrecks they are currently unable to indicate their degradation state. To assess the sensitivity of acoustic measurements to changes in the degradation state of such material, and hence the potential for sonars to quantify degradation, laboratory measurements of compressional wave velocity, as well as bulk density for oak and pine samples, in varying states of decay, were undertaken. These data enabled the calculation of theoretical reflection coefficients for such materials buried in various marine sediments. As wood degrades, the reflection coefficients become more negative, resulting in the hypothesis that the more degraded wood becomes, the easier it should be to detect. Typical reflection coefficients of the order of −0.43 and −0.52 for the most degraded oak and pine samples in sand are predicted. Conversely, for wood exposed to seawater the predicted reflection coefficients are large and positive for undegraded material (0.35 for oak, 0.18 for pine) and decrease to zero or slightly below for the most degraded samples. This indicates that exposed timbers, when heavily degraded, can be acoustically transparent and so undetectable by acoustic methods. Corroboration of these experimental results was provided through comparison with high resolution seismic reflection data that has been acquired over two shipwrecks.  相似文献   

Modelling of periodic wave transformation in the inner surf zone     

P. Bonneton   《Ocean Engineering》2007,34(10):1459-1471

In this paper, we analyse the ability of the nonlinear shallow-water (NSW) equations to predict wave distortion and energy dissipation of periodic broken waves in the inner surf zone. This analysis is based on the weak-solution theory for conservative equations. We derive a new one-way model, which applies to the transformation of non-reflective periodic broken waves on gently sloping beaches. This model can be useful to develop breaking-wave parameterizations (in particular broken-wave celerity expression) in both time-averaged wave models and time-dependent Boussinesq-type models. We also derive a new wave set-up equation which provides a simple and explicit relation between wave set-up and energy dissipation. Finally, we compare numerical simulations of both, the NSW model and the simplified one-way model, with spilling wave breaking experiments and we find a good agreement.  相似文献   

First results from the North Iceland experiment     

C. Riedel  A. Tryggvason  B. Brandsdottír  T. Dahm  R. Stéfansson  M. Hensch  R. Böðvarsson  K. S. Vogfjord  S. Jakobsdottír  T. Eken  R. Herber  J. Holmjarn  M. Schnese  M. Thölen  B. Hofmann  B. Sigurdsson  S. Winter 《Marine Geophysical Researches》2006,27(4):267-281

Between June 2004 and September 2004 a temporary seismic network was installed on the northern insular shelf of Iceland and onshore in north Iceland. The seismic setup aimed at resolving the subsurface structure and, thus, the geodynamical transition from Icelandic crust to typical oceanic crust along Kolbeinsey Ridge. The experiment recorded about 1,000 earthquakes. The region encloses the Tjörnes Fracture Zone containing the Husavik–Flatey strike-slip fault and the extensional seismic Grimsey Lineament. Most of the seismicity occurs in swarms offshore. Preliminary results reveal typical mid-ocean crust north of Grimsey and a heterogeneous structure with major velocity anomalies along the seismic lineaments and north–south trending subsurface features. Complementary bathymetric mapping highlight numerous extrusion features along the Grimsey Lineament and Kolbeinsey Ridge. The seismic dataset promises to deliver new insights into the tectonic framework for earthquakes in an extensional transform zone along the global mid-ocean ridge system.  相似文献   

海洋沉积物声速与物理参数的关系   总被引：4，自引：0，他引：4       下载免费PDF全文

卢博  梁元博 《海洋科学》1993,17(6):54-57

海洋沉积声速与物理性质密切相关，特别是含水量Ｗ和孔隙度Ｎ，它们在建立回归议程和预报沉积物性质中有所贡献。中国东，南海沿海沉积物的资料和数据表明：声速和声速比可以用来预报沉积物性质。  相似文献   

渤海湾沿岸泥炭沼泽形成机制与时空分布   总被引：4，自引：0，他引：4  

李汉鼎  王升忠 《海洋地质与第四纪地质》1995,15(2):11-16

渤海湾沿岸的海陆过渡带，优越的水文地理环境有利于泥炭沼泽的形成与发育。海洋海退导致的海岸线变迁，是控制泥炭沼泽发育时间和空间分布的主导因素。间冰期和冰后期的海面上升期间，自海向陆发育了海侵基底泥炭；中全新世高海面期，在山前扇缘洼地和沟谷有泥炭沼泽发育；晚全新世海面下降期，泥炭沼泽主要发育在沿岸的海湾、泻湖、三角洲汊河间洼地及平原上的河滩、阶地、古河道等地。  相似文献   

珠江口现代沉积速率及其反映的沉积特征   总被引：2，自引：0，他引：2  

陈耀泰  罗章仁 《热带海洋学报》1991,(2)

文章分析了珠江河口海区泥沙来源及淤积动态,采用以历史海图分析对比为主,~(210)Pb测年数据校核等方法,参考有关沉积速率定性方面的标志,推算出珠江口不同地段的现代沉积速率,并相应划分出高速率沉积、快速率沉积、中速率沉积和慢速率沉积或稍有侵蚀等4个分区.进而,还论述了沉积作用的特征.  相似文献