A Whitecap Coverage Model Based on the Surface Slope For Criterion of Wave Breaking   总被引：3，自引：2，他引：1  

Xu Delun  Yu Dingyong  Lu Hongmin Professor  Physical Oceanography Laboratory  Ocean University of Qindao  Qingdao Associate Professor  Engineering School  Ocean University of Qindao  Qingdao Senior Engineer  Physical Oceanography Laboratory  Ocean University of Qingdao  Qingdao 《中国海洋工程》1998,(1)

Using the limit surface slope as a criterion of wave breaking,a simple model for estimatingthe spatial fraction of breaking surface of sea at an instant,which is regarded as the whitecap coverge inthis paper,is analytically derived from the probability density of surface slope based on Gaussianstatistics.The resulting fraction is found depending on the fourth moment of wave spectum,m_4,as well asthe critical threshold of surface slope.By expressing the fourth moment in terms of the Neumannspectrum,a formula linking the fraction and wind speed for fully developed sea states is obtianed.Anotherformula relating the fraction to both wind speed and fetch(or duration)is achieved by expressing m_4 interms of the Krylov spectrum and applying the empirical relationships used in the SMB ocean wave pre-dicting technique.A comparison between these results and the field data of whitecap coverage collected byMonahan and O＇Muircheartuigh shows an encouraging agreement.  相似文献   

三维地震相干应用研究新场、东泰及合兴场实例分析     

杨振武 《物探化探计算技术》1999,21(4)

本文研究了新场、东泰及合兴场三维地震相干及应用后认为：①断层、地层特征的不连续性通过三维地震相干数据体的低相干异常,能够获得十分清晰、直观的展示;②地层特征的连续性通过三维地震相干数据体的高相干异常能够得到非常清楚、明显的表现  相似文献   

西北太平洋黑潮主轴区浮游有孔虫的垂直分布及其古海洋学意义   总被引：5，自引：0，他引：5  

徐学东  宇田理重  土桥正也  尾田太良 《第四纪研究》1999,19(6):502-510

我们对位于西北太平洋黑潮主轴区ＭＴＤ－０２站的１１个不同深度进行水平浮游拖网,并将采集到的活体浮游有孔虫(＞１２５μｍ)进行定量分析。结果表明,绝大多数活体浮游有孔虫生存于１００～２００ｍ以上的水体中,并集中分布于７５ｍ以上的水体。本站位８月份的最主要属种为：Ｇｌｏｂｉｇｅｒｉｎｏｉｄｅｓｒｕｂｅｒ,Ｇ．ｓａｃｃｕｌｉｆｅｒ,Ｎｅｏｇｌｏｂｏｑｕａｄｒｔｎａｄｕｔｅｒｔｒｅｉ和Ｇｌｏｂｉｇｅｒｉｎｉｔａｇｌｕｔｉｎａｔａ。次主要属种为Ｇｌｏｂｉｇｅｒｉｎｅｌｌａ　ａｅｑｕｉｌａｔｅｒａｌｉｓ,　ｇｌｏｂｉｇｅｒｉｎａｂｕｌｌｏｉｄｅｓ,Ｐｕｌｌｅｎｉａｔｉｎａｏｂｌｉｑｕｉｌｏｃｕｌａｔａ,Ｇｌｏｂｏｒｏｔａｌｉａｔｒｕｎｃａｔｕｌｉｎｏｉｄｅｓ,Ｏｒｂｕｌｉｎａｕｎｉｖｅｒｓａ和Ｇ．ｃｏｎｇｌｏｂａｔｕａ。这些种在不同的深度其产出量大不相同,但绝大多数均在叶绿素最为丰富的２５ｍ处显示出最大值。这表明食物来源是控制浮游有孔虫在ＭＴＤ－０２站垂直分布的最主要因素。另外,Ｇｌｏｂｉｇｅｒｉｎｅｌｌａａｅｑｕｉｌａｔｅｒａｌｉｓ和Ｐｕｌｌｅｎｉａｔｉｎａｏｂｌｉｑｕｉｌｏｃｕｌａｔａ两个种在温跃层的底部５０ｍ处显  相似文献   

The coherence coefficient map and residue guided least square phase unwrapping algorithm   总被引：1，自引：0，他引：1  

ZHANG LiLIAO MingshengZHANG ZuxunZHANG Yong ZHANG Li  Doctoral Candidate  National Laboratory for Information Engineering in Surveying  Mapping  Remote Sensing  WTUSM  Luoyu Road  Wuhan  China 《地球空间信息科学学报》1999,2(1):55-62

  相似文献   

海口港风暴潮分析与预报   总被引：2，自引：1，他引：1  

丁千龙 《海洋预报》1999,16(1):41-47

本文根据海口港１９７１～１９８９年的实测潮位资料和有关文献,利用差值法分离出台风增减水的过程曲线,对海口港风暴潮的特性和引起增减水的物理机制进行了初步分析。采用经验方法确定了导致本站增水的主导风向及最大的区域,建立了增水极值与本站风力、气压的相互关系,并通过逐步回归分析,给出了海口港风暴潮过程预报方程。最后利用１９９０、１９９１两年的实测资料对预报方程进行了后报检验,结果表明,预报与实测值的吻合程度较好。  相似文献   

末次盛冰期以来长江三角洲地区的沉积相和古地理   总被引：16，自引：6，他引：10       下载免费PDF全文

李从先  陈庆强  范代读  张家强  杨守业 《古地理学报》1999,1(4):12-25

末次盛冰期低海平面期间,长江三角洲地区可划分为2个古地理单元：古河谷和古河间地。下切河谷底部侵蚀面和古河间地顶面构成了冰后期海侵沉积旋回的底界面,它相当于层序地层学中的层序界面。位于河口湾-浅海相中的最大海侵面将冰后期海侵沉积旋回分为其下的海侵层序和其上的海退层序。随着δ¹⁸O ₃期的海平面下降,长江开始下切,至δ¹⁸O ₂期低海面时形成巨大的下切河谷。冰后期海平面上升引发的海侵造成了长江古河谷系的充填和河床、河漫滩－河口湾和部分河口湾－浅海相的形成,尔后的进积产生了部分河口湾－浅海相及三角洲相等。溯源堆积是产生下部河流沉积单元的主要过程,其中河漫滩沉积中出现的潮汐层理和少量小个体有孔虫说明了海洋因素的影响,河口湾－浅海相泥质沉积主要形成于最大海侵之时,三角洲的进积则产生了具有多期河口坝的三角洲。古河间地表面的硬粘土层经历了沉积和成壤作用交替、持续成壤作用和早期成岩作用,它们大致分别对应于δ¹⁸O ₃期、δ¹⁸O ₂期和δ¹⁸O ₁期,硬粘土层中留下了这3种作用的烙印。长江三角洲古河间地的古土壤母质属河漫滩相。持续成壤阶段河流基面和地下水位均较低,年降雨量约为500～800 mm,相当于现今的温带地区,干湿周期变化明显,地下水升降频繁。所有这些表明,当时并非干旱气候。  相似文献   

ON CHANGES OF CHINA’S MAXIMUM AND MINIMUM TEMPERATURES IN 1951-1990          下载免费PDF全文

Zhai Panmao  Ren Fumin 《Acta Meteorologica Sinica》1999,13(3):278-290

Based on China's observational data in 1951-1990,after minimizing the possible biases caused by station relocation and urban heat island,the spatial and temporal distributions of trends for maximum and minimum temperatures are studied.The results show that increasing trends of maximum temperatures are in the areas west to 95°E,and north to the Huanghe (Yellow) River,while decreasing trends exist in eastern China south to the Yellow River.Minimum temperatures are generally increasing throughout China,with dominant warming trends at the higher latitudes.This resulted in very obvious decreasing trends in diurnal temperature ranges.The periodic cycles are consistent between the maximum and minimum temperatures,but asymmetric trends are very obvious.The significant increase of minimum(nighttime) temperatures reflects the evidence of enhancement of greenhouse effect.Further analysis shows that the changes of maximum and minimum temperatures are mainly related to sunshine duration and atmospheric water vapor content.  相似文献   

带周期项的海平面变化灰色分析模型及广西海平面变化分析   总被引：7，自引：0，他引：7  

夏华永  李树华 《海洋学报》1999,21(2):9-17

提出了一种带周期项的海平面变化灰色分析模型.该模型保持了GM(1,1)模型能较好反应海平面变化趋势的优点,不仅能求出海平面变化速率,还能方便求出海平面变化的加速度,同时,该模型能较好的模拟海平面变化中的周期现象,从而克服了GM(1,1)不能预报周期性显著的月平均海面的缺点,并提高了预报精度.模型用于广西沿岸海平面变化分析,结果表明北海、涸洲、白龙尾3站的相对海平面上升速率分别为1.67、2.51、0.89mm/a;石头埠相对海平面呈下降趋势,下降速率为0.5～1.0mm/a;广西沿岸绝对海平面上升速率为2.0mm/a.和线性趋势项与周期项叠加的海平面分析模型相比,两者模拟精度相当.  相似文献   

A grey model with periodic term for sea-level analysis and its application to the Guangxi coast     

Xia Huayong  Li Shuhua 《海洋学报(英文版)》1999,18(3):325-335

A~as~Sof~~LIngeneral,sealevelisresolvedintOatrendtermplusaPeriedictermintheanalysisofsealevelvdriations(haetal.1996;ZuoandChen,1996;QinandLi,1997;Zhengetal.,1993;RenandZhang,1993),namely,thetimeequencesofmonthlyorannualmeansealevely(o)(t)canbeexpr~asy(o)(t)=T(o)(t) p(o)(t) X(o)(t) .(o)(t),(l)whereT(o)(t)isadefinitetrendterm;p(o)(t)isadefiniteperiedicterm;X(o)(t)isatimeseriesofrandomterm;a(o)(t)iswhitenoise.Thefunctionstructuresofthetrendtermaregenerallyunknown,whiledeterminingthetrendter…  相似文献   

A laboratory study of directional spectra with maximum likelihood mehod-Ⅱ Decaying swell     

Zhao Dongliang  Masuda Akir  Wen Shengchang  Guan Changlong 《海洋学报(英文版)》1999,18(1):75-85

INTRODUCTIONForavarietyofapplications,includingcoastalandoceanengineering,shiproutingandtheinterpretationofremotelysensedata,informationonthedirectionalwavespectrumisdesirable.Knowledegeoftheintegratedorone-dimensionalspectrumisconsiderable,duelargelytofieldmeasurementssuchasJONSWAP.Asimilarsituation,however,doesnotexistinthecaseofdirectionalsprectra.Thisislargelyduetotheaddedcomplexityandthecostofdirectionalmeasure1.InstituteofPhysicalOceanography,OceanUniversityofQingdao,Qingdao266…  相似文献