共查询到20条相似文献，搜索用时 46 毫秒
1.
水团的识别与划分一直是物理海洋学的重要研究内容。本研究采用模糊密度聚类方法划分水团，并利用Fortran语言编制了该模型：同时，在Visual Basic 6．0环境下，利用MapX控件进行了GIS平台开发；并将两者紧密集成，使得水团分析的所有阶段，包括计算网格的获取、温盐场数据的提取和插值、模型的参数选择和设置、模型的计算以及最终结果的可视化等都在同一环境下完成，大大提高模型应用的数据分析和决策的效率。将该系统应用于舟山渔场及其邻近海域，所得结果比较理想。 相似文献
2.
变性水团软划分的一种FUZZY模式 总被引：1，自引：0，他引：1
在已知研究海区水团核心的前提下,考虑到各种指标对标识水团的不同贡献,提出了一种水团软划分的FUZZY模式。利用1987年5—6月黄东海的温、盐和溶解氧实测资料进行计算,与已有成果作了对比,结果令人满意。 相似文献
3.
东海北部是鲐鱼主要渔场之一 ,研究其水文及其变化特征对于掌握鲐鱼中心渔场的时空变化规律、指导渔业生产、合理利用海洋渔业资源具有重要意义。根据 1 987— 2 0 0 1年在 2 9°— 32°N、1 2 4 5°E以西海域的海洋环境调查资料和鲐鱼渔场资料 ,在GIS平台上 ,用最优隶属模型划分水团 ,并研究渔场的水团和温、盐跃层特性及其月、年变化之间的相关性 ,用于渔情预报。研究表明 ,用最优隶属模糊聚类方法划分该海域水团的结果与以往的研究结果比较一致 ;鲐鱼渔情与该区域水团第一强度、第二强度之间显示了一定的相关性 ;用稳健统计学方法 ,可确定中心渔场的底层、鱼类栖息水层的温盐范围及其聚类中心值 ;鲐鱼渔情、渔场与水文跃层的关系密切。 相似文献
4.
5.
应用Argo资料分析西北太平洋冬、夏季水团 总被引：1，自引：0，他引：1
应用Argo剖面浮标观测的温、盐度资料,分析了西北太平洋海域冬、夏季的温、盐度分布、水团结构及其分布。首先采用T-S点聚图法分析了该海域水团分布的基本情况,由点聚分析结果可知,该海域至少存在6种以上水团;再用模糊聚类软化法对水团作进一步划分,分别计算了该海域6至11类水团的F和△F值,结果表明,冬、夏季的△F值都以划分为8类时为最大,这与大洋水团的稳定性是一致的,因此,该海域冬、夏季水团以划分为8类最佳,它们分别是北太平洋热带表层水、北太平洋次表层水、北太平洋中层水、北太平洋副热带模态水、北太平洋深层水和赤道表层水,以及南太平洋次表层水和南太平洋中层水。 相似文献
6.
模糊数学方法在南海北部海区水团分析中的应用 总被引：9，自引：2，他引：9
本文将模糊数学的多种方法,用于南海北部海区的水团分析.在用模糊聚类方法划分水团时,提出了基于欧氏距离的相似关系,同时提出了基于F-检验而决定水团个数的方法.以模糊聚类划出的水团为基础,再用软划分方法,对水团边界和测样归属进行合理调整.根据上述结果及区域海洋学的分析,在该海区划出了8个水团:沿岸冲淡水团F、近岸混合水团M、暖表层水团WS、表层水团S、表次层混合水团SU、次层水团U、次中层混合水团UI和中层水团I.将各类水团在-S图解上的点集,归结为变形椭圆凸点集、半无界凸点集和单侧凹点集3种类型.分别提出了建立相应隶属函数的方法,并给出了拟合结果.计算了各季节各水团的熵,讨论了高熵和低熵水团的特征及形成原因.计算了各季节不同水团之间的格贴近度,借以讨论水团变性的特点和它们之间的相互关系.可将8个水团归纳为3种类型:径流冲淡型(F),浅海变性型(M、WS、S和SU),深海大洋型(U、UI和I). 相似文献
7.
应用Argo资料分析西北太平洋冬、夏季水团 总被引：1，自引：0，他引：1
应用Argo剖面浮标观测的温、盐度资料，分析了西北太平洋海域冬、夏季的温、盐度分布、水团结构及其分布。首先采用T-S点聚图法分析了该海域水团分布的基本情况，由点聚分析结果可知，该海域至少存在6种以上水团；再用模糊聚类软化法对水团作进一步划分，分别计算了该海域6至11类水团的F和△F值，结果表明，冬、夏季的△F值都以划分为8类时为最大，这与大洋水团的稳定性是一致的，因此，该海域冬、夏季水团以划分为8类最佳，它们分别是北太平洋热带表层水、北太平洋次表层水、北太平洋中层水、北太平洋副热带模态水、北太平洋深层水和赤道表层水，以及南太平洋次表层水和南太平洋中层水。 相似文献
8.
在文献[1]中,我们提出了水团模糊聚类划分的理由、原理;并且以1976年10月南海北部某一水域的资料为例,利用模糊聚类的原理作了水团划分的尝试,得到了比较合理的结果。在文献[2]里,我们以文献[1]为基础,建立了水团的模糊子集,运用隶属函数法,研究了如何确定水团的边界位置及混合带(层)的宽(厚)度问题。但是,有关水团个数的确定以及水团间的均匀化过程,上述文献均未具体涉及。有鉴于此,本文进一步假定每一个观测站(层)的海洋水文要素值代表了该测站(层)的小邻域内的海 相似文献
9.
10.
我国东部海域受近岸流、台湾暖流和黑潮的影响,不同水团间环境因子差异较大,甲藻作为初级生产者主要受环境影响,研究分析不同水团浮游甲藻群落组成及分布情况具有重要的生态意义。2014年5-6月,本研究对台湾以东黑潮主流径及东海200m等深线内陆架区进行采样调查,分析测站浮游甲藻的群落结构组成。研究结果表明,网采样品共鉴定出浮游甲藻17属81种,甲藻丰度范围为（0.45-1207.86）×103cell/m3。根据聚类分析结果,将海区浮游甲藻划分为3个群落类型,分别为受沿岸水团影响的群落Ⅰ、受台湾暖流水团影响的群落Ⅱ和黑潮水团影响的群落Ⅲ。不同水团间甲藻群落结构具有一定差异性,其中甲藻丰度变化趋势为沿岸水团 > 台湾暖流水团 > 黑潮水团,沿岸水团甲藻主要以广温广盐种为主,台湾暖流水团甲藻以广温高盐种为主,黑潮水团甲藻以高温高盐种为主。 相似文献
11.
Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
12.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
13.
The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
14.
Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
15.
16.
《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
17.
Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
18.
Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献
19.
This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner. 相似文献
20.
Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream. 相似文献