An Introduction to 2-CCD Digital Particle Image Velocimetry System and Its Application in Ocean Engineering     

Daichin  Timothy P.Dewhirst 《中国海洋工程》1997,(3)

The basic principle of particle image velocinmetry(PIV)is described.When a PIV image is an-alyzed by the method of auto-correlation,there is a direction ambiguity of 180~0 in velocity measurement.The problem can be solved by using"Image Shifting Technique",but this makes devices much complicat-ed and difficult to control.A new arrangement of 2-CCD(Charge Coupled Device)fully digitized PIV sys-tem,which can also solve the problem successfully,is introduced in the paper.As an example of applica-tion of the system,an experimental result of flow field around a horizontal cylinder in wave is presented.  相似文献   

高能波控陆架的风暴沉积和风暴层序——以澳大利亚东南部陆架为例          下载免费PDF全文

李从先  庄武艺  P.S.Roy 《海洋学报》1993,15(2):63-72

根据浅层地震和钻孔资科,将澳大利亚东南部研究地区高能波控陆架风暴沉积分为直立风暴层、叠瓦状风暴层、无序风暴层、水平风暴层和纹层状风暴层等五类。各类风暴层及风暴层与非风暴层组合而成悬移风暴层序、悬移-推移混合风暴层序和推移风暴层序三大类。中陆架风暴沉积与现今近岸和水下岸坡相似,岩性、岩相和古生物属海岸带,风暴沉积厚,底板埋深大,组成物质粗。推断中陆架风暴沉积当形成于冰后期海侵、该地带处在近岸带和水下岸坡环境时,此时海面上升速度可能减缓,或趋近于零,甚至可能有短时间的下降。  相似文献   

Conservation of Mediterranean seascapes: analyses of existing protection schemes     

Fraschetti S  Terlizzi A  Bussotti S  Guarnieri G  D'Ambrosio P  Boero F 《Marine environmental research》2005,59(4):309-332

Marine protected areas (MPAs) are aimed at managing and protecting marine environments. Their design, however, often disregards both a thorough knowledge of the distribution of habitats and assemblages and the use of proper experimental evaluations of the efficacy of MPAs by comparing protected vs. unprotected zones. About 200 MPAs have been recently instituted in the Mediterranean area, but the evidence of their efficacy is scant. The MPA of Torre Guaceto (Southern Adriatic Sea, Italy) is one of the rare cases of effective protection enforcement. The reserve was instituted more than 10 years ago, a period currently considered as sufficient to show responses by organisms to protection. The MPA is divided into a C zone, the general reserve, where many activities are permitted, a B zone, the partial reserve where restrictions increase and two A zones, the integral reserve where access is prohibited. The goals of the paper were to map the distribution of benthic assemblages to assess if they were properly represented in the differently protected zones, and to test the efficacy of protection by quantifying possible differences between the assemblages in two control areas and in the two A zones, where human impact is completely excluded. The analysis of habitat and assemblage distribution within the MPA showed that the zones with total protection do not include most valuable environmental types. Most of the considered variables (i.e. cover of substratum, number of taxa, and average abundance of the most common taxa) were not significantly different in and out of the A zones, at each time of sampling. Results, however, suggested a possible effect of protection in modifying patterns of abundance of sponges under Cystoseira canopy (more abundant in the fully protected zone). In the subtidal habitat, differences were found in the structure of the whole assemblage and in the abundance of encrusting coralline red algae (more abundant outside the fully protected area). Notwithstanding the correct general methodology employed in the study, a lack of statistical power could have a role in preventing the detection of ecologically relevant effects of protection. In some instances, data pooling allowed a discrimination between cases where there was clearly no effect of protection and cases where there might be. On this basis, the optimization of this experimental design should be considered in further studies. In any case, if the goals of MPAs have not been clearly stated, efficacy of protection might prove very difficult to test even with the use of sound experimental designs.  相似文献   

海上净化实验舱     

C.S.Wong  W.J.Cretney  J.Piuze  P.Christensen  P.G.Berrang 《海洋科学》1982,6(1):60-62

已报道的关于大洋水中某些痕量金属的基线浓度,总的说来是随着经历的年代而一直在减少的。这样,在文献中看到的大部分有关痕量金属浓度的数据就似乎没有什么价值,而只不过是污染水平的指标罢了,因为,实验室之间精心的相互校正实践已证明,只有严格净化的采样、操作和分析技术才会产生准确的数据。  相似文献   

2万年来热带温度变化：调节半球间的气候变化     

T.P．Guilderson胡季平  陈宗团 《海洋地质前沿》1995,(1):17-19

２万年来热带温度变化：调节半球间的气候变化Ｔ．Ｐ．Ｇｕｉｌｄｅｒｓｏｎ等世界范围内因ＣＯ＿２含量倍增引起的全球温度变化估计为１°－４℃，这与热带海洋表面温度（ＳＳＴｓ）的变化非常相似。相似的热带ＳＳＴｓ变化范围（＋１°－＋３℃）显然取决于全球循环模型...  相似文献   

越南东南陆架及陆坡区油气地质调查     

K.  PГ 陈邦彦 《海洋地质》1992,(1):36-52

  相似文献   

澳大利亚海洋生物研究概况     

P.哈钦斯  吴宝铃 《海洋科学》1987,11(2):54-57

澳大利亚从事海洋生物研究的单位很多。下面我们仅扼要介绍一下其主要研究机构、经费来源及研究概况。 一、海洋生物的主要研究机构、 澳大利亚共有19所大学,主要分布在州政府所在地。除一所大学之外,这些大学都设有生物系。这些系都从事一定的海洋研究,只不过其中有些系更偏重海洋生物学研究而已。北昆士兰詹姆斯·科克大学海洋生物学在生物系享有一定地位,而其它大学在生物  相似文献   

墨西哥南下加利福尼亚上新世洛雷托盆地构造与加利福尼亚湾的演化     

P．J．Umhoefer高莉玲  张光威 《海洋地质前沿》1995,(2):15-16

墨西哥南下加利福尼亚上新世洛雷托盆地构造与加利福尼亚湾的演化Ｐ．Ｊ．Ｕｍｈｏｅｆｅｒ等洛雷托盆地滨岸部分位于南下加利福尼亚州洛雷托正北的加利福尼亚湾沿岸，面积１５×５０ｋｍ。在盆地南部，上上新统沉积岩覆于中新统火山岩之上。这些沉积物沿着盆地西南边缘洛...  相似文献   

黄、东海及其邻海的气旋与埃尔尼诺现象     

龙宝森  Howard P. Hanson 《海洋科学进展》1985,(3)

一、序言ENSO现象对全球大气环流及其伴随天气的影响,一直是近年来海气相互作用研究的焦点之一,一些有趣的研究表明,ENSO现象对中纬度气候有显著的影响.本文统计了1899-1962年每年发生在20°-40°N,120°-150°E区域(图1)以及主要气旋活动中心(图1阴影  相似文献   

亚洲的传播挤出构造：从简单的塑泥挤压实验...     

Tappo.  P 袁友仁 《南海研究与开发》1990,(4):23-31

  相似文献