共查询到20条相似文献，搜索用时 468 毫秒
1.
Analysis of the sections traversing the polar hydrological front on the shelf of the North-European basin has enabled us to reveal the areas limited by closed isotaches of the sound velocity existing in the interfrontal zone at depths of 50–150 m. These areas represent the closed waveguide which has the property of an underwater sound channel.Translated by Mikhail M. Trufanov. 相似文献
2.
东太平洋CC区板块构造和多金属结核资源效应探讨 总被引：4，自引：0，他引：4
利用东太平洋CC区多波束海底地形测量、结核覆盖率深拖系统探测、结核丰度地质采样和地球物理地震勘探资料,运用板块构造和沉积动力学理论,并与丰度趋势面和神经网络分析结果对比,对东太平洋CC区构造与多金属结核资源效应关系进行了探讨,并认为:(1)富集在研究区约200亿t结核的最主要控制因素是东太平洋海隆、莱恩山脉、克拉里昂-克利伯顿大断裂(Clarion-Clipperton Fracture Zone),东、西、南、北的四个构造单元为结核大量富集起到了框架性的关键作用;(2)本区经历了和遵循着海底扩张的基本过程,这个过程对结核物质来源、成矿作用、结核分布有重大影响,结核丰度、覆盖率与地形变化非常一致,重大相变距离为10～15km,基底自形成以来一直影响着地表结核;(3)地球深部地质作用过程对结核成矿作用也有一定影响,影响因素可能涉及基底岩浆房及其大小等. 相似文献
3.
On the basis of the results derived by theoretical analysis [1] and laboratory physical modelling [2] of the circulation seawater
and stratification, induced by buoyancy fluxes, the suggestion has been made that, possibly, the Black Sea currents system
is three-layered. It has been supposed that an anticyclonic current flows in the basin.
To verify this deduction, the data from MHI's archived dataset have been treated, and results from twoad hoc expeditions are submitted here. Analysis of the vertical structure of currents, based on thein situ velocity measurements, using various means and calculations of the geostrophic circulation, has confirmed that a flow with
the theoretically predicted parameters may exist in the Black Sea.
Translated by Vladimir A. Puchkin. 相似文献
4.
近年来长江河口北支水沙特性与河槽稳定性分析 总被引：3，自引：0，他引：3
根据崇头、青龙港、三条港和连兴港1950～2001年潮汐潮流观测资料和2005年6～7月的大、中、小潮及2007年5月5～10日沿北支河槽进行的两个连续潮周期水、沙、盐的现场观测数据并结合参考2005年的实测地形图.通过对长时间序列(1950～2001年)的分流比、年均流量、潮位、潮历时等数据的整理分析并与近期(1998～2005年)的水文特征值比较,发现随着北支分流量逐渐减少,河槽内强烈的潮波已成为影响北支河槽不稳定的主要因素;青龙港近年来(1998～2005年)平均高、低潮位出现增高,比多年(1950～2001年)平均高、低潮位分别高出15和17cm,是北支河床近年来持续性淤浅的体现;大潮期间北支河槽涨潮含沙量无论量值还是扩散强度均大于落潮,明显表现出河口涨潮槽具有的泥沙运动规律.自2001年以来除少数年份的小潮汛外,均表现出明显的涨潮优势,其中2002年3月大潮的潮量优势流仅为9.42%,显示出涨潮优势十分明显,说明北支河槽近几年来正朝着衰退的过程发展;2005年北支河槽-2、-4和-6 m等深线均呈喇叭状,闭合端指向上游,符合涨潮槽的几何形态;再从河槽类型系数(λ)看,大潮期间λ值均大于1,最大值为31.1,涨潮槽特征显著;而洪季中、小潮各测站λ值均小于1,最小值为0.000 3,A、B两测站在大潮时λ值均大于1,而小潮时又都小于1,显示北支河槽虽主要表现为涨潮槽的特征,但洪季受径流和潮汛影响,其涨潮槽特性不稳定.总体而言,目前北支河槽为一条不稳定的废弃型涨潮槽. 相似文献
5.
近年来,长江中下游来沙量持续性减小,其对河床冲刷的效应已逐渐在长江口显现。然而,长江口河床容积的变化特征缺少定量研究,与来沙量减小的时空响应规律不明确。通过分析长江大通站、徐六泾站的泥沙资料,并统计不同高程下的河床容积随时间变化特征,建立不同区段、不同高程河床容积与上游不同时段平均来沙量的关系。结果表明,大通站2003—2020年的年输沙量较三峡工程建成前有大幅减少,其对徐六泾站的当年洪季含沙量有着直接且显著的影响。长江口南支0 m以下河床处于冲刷态势,2003年后河床冲刷速率有明显增加,其中-10 m以下深槽部分的冲刷量贡献最大。南支主要落潮通道河床容积与前1年大通平均来沙量具有显著的相关性,因此来沙量减小主要引起长江口落潮通道河床容积增加,其效应具有约1 a的滞后性。 相似文献
6.
E. V. Kaplya 《Izvestiya Atmospheric and Oceanic Physics》2016,52(7):760-767
Statistical regularity in the dynamics of wind direction has been found. The density distribution of the increment of the wind-direction angle has been approximated using a generalized advanced logistic distribution. The advanced logistic distribution involves an additional power-law parameter. The parameters of the approximation function have been computed from experimental data using the method of least squares. The consistency of the proposed function with meteorological data has been tested using Pearson’s chisquared test and the Kolmogorov test. 相似文献
7.
8.
A three-year study of the abrasion of coarse fragmental material on the Murmansk coast has been carried out. According to
the researchers, the average rate of the abrasion of the coarse-fragmental material of granitoid composition on the Murmansk
coast has been determined. It was revealed that the rate of the destruction of the blocks increases from the lower littoral
zone to the upper one. The estimation of the quantity of sedimentary material coming to the sedimentation basin as a result
of the abrasion of coarse-fragmental material has been carried out. 相似文献
9.
10.
On the basis of the experimental investigations conducted from an oceanographic tower, the variability of the structure of
temperature profiles has been analysed. The paper provides a classification of the basis types of temperature profiles and
determines their frequencies and duration in the annual cycle. Dynamics of the transition from one type of a temperature profile
to another has been found to have synoptic scales. The variability of parameters during an occurrence of some typical profile
have been assessed; it has been deduced that variations in profile shape are linked with fine structure effects of internal
waves.
Translated by Vladimir A. Puchkin. 相似文献
11.
The contribution of turbulence to the electrification of thunderstorm clouds is considered for the first time using a model of the large-scale electric field generation in a weakly conducting media containing two fractions of colliding hydrometeors. The calculation results are compared with experimental data. It has been found that scenarios of electric-field generation and growth are significantly different for inductive and noninductive charging mechanisms. The range of thundercloud parameters (of conductivity and particle radii) for which the electric field grows exponentially in the case of inductive charging has been found. In the case of noninductive charging, it has been shown that the electric field strength grows linearly in time due to intensive fluctuations of the electric charge. The linear growth of the electric field can be a significant factor when approaching the threshold of the discharge initiation. 相似文献
12.
全球变化影响下青岛海岸带地理环境的演变 总被引：8，自引：1，他引：7
在全球变化的影响下,近50多年来青岛海岸带地区的地理环境要素发生了许多超常的变化。其中,年平均气温1991-2002年比20世纪50年代上升了0．94℃,同期最冷月1月平均气温上升了2．18℃,≥10℃的天数由每年207．6d增至218．5d,近海年平均海水温度在20世纪60年代为13．45℃,而1991-2002年为14．20℃,上升了0．75℃。海岸沙滩侵蚀加剧,20世纪90年代以来灵山湾每年蚀退达7m;胶州湾面积由1952年的559km。缩减为2002年的382km^2;滨海漏湖湿地几乎全部消失。由于海岸带气候和水温的变暖使研究区动植物群落发生变化,如茶树从南方引中成功并形成产业,一些本来在长江三角洲地区越冬的鸟类（如大天鹅）已迁至山东半岛越冬;某些生活在温暖海洋中的海洋动物也频现青岛。 相似文献
13.
《Marine Policy》2007,31(5):628-631
This paper focuses on the revision to the Bathing Water Directive and its likely implications for local authorities in the United Kingdom. It outlines the proposal and its current status in European negotiation and the likely outcome. It then details the work the Solent Forum, in particular a subgroup that focuses on water quality, the Solent Water Quality Association, has done in relation to the proposed revision and their implications for coastal local authorities. Initially, this group considered what the implications for coastal local authorities might be through a national conference and has since concentrated on ensuring authorities at the local level are prepared for the enhanced responsibilities the changes will place on them. This has been achieved through individual project work related to ensuring beach management plans are in place for incidents of non-compliance, undertaking research at local beaches to understand the needs of the public vis-a-vis information, and hosting national events to share best practice. 相似文献
14.
15.
16.
长江口南支涨潮槽新桥水道冲淤变化的定量计算 总被引：8，自引：3，他引：5
根据1861~2002年100多年中的15幅海图资料,以GIS技术为支持,建立不同时期长江口水下数字高程模型(DEM),对长江河口南支涨潮槽新桥水道进行了冲淤变化的定量计算,并对比计算了多年来新桥水道0m岸线和5m等深线以及横断面的演变.计算结果显示在所研究的区域内自1861年以来新桥水道冲淤过程明显被分为三个阶段:1861~1926年的66a间新桥水道区域经过一段时间的冲刷后又重新产生淤积,总容积变化不大;1926~1958年的33a间新桥水道在不断的冲刷中总容积由2.603亿m3增长到5.076亿m3;1958年至今的45a时间里水道容积基本保持在平均5.02亿m3.1926年新桥水道10m等深线已经形成一定的格局.1947年5m等深线向上延伸,扁担沙已经不再与崇明岛相连;1958年上下扁担沙的5m等深线基本连成一体,可以认为此时新桥水道已经形成.从新桥水道的横断面变化来看,其主泓不断发生变化,主泓经历了向北移的过程,移动约为1.1~2.8km. 相似文献
17.
长江口横沙东滩近30年来自然演变及工程影响的GIS分析 总被引：1，自引：0，他引：1
利用长江口深水航道治理一、二期工程实施前后的地形资料,在GIS软件及相关的统计分析软件的支持下,分析了治理工程对横沙东滩冲淤演变的影响。结果表明:横沙东滩在长期的自然演变过程中滩地面积相对稳定,但20世纪90年代中期以来,由于长江来沙量减少,滩地面积出现减小的趋势;深水航道北导堤工程(1998—2000年5月)使横沙东滩的冲淤形势发生了较大的变化:横沙东滩窜沟扭曲、萎缩,白条子沙及其以东浅水区域淤积加剧;促淤工程实施后,形成了一个有利泥沙沉积的环境,过境泥沙的大量淤积及人工吹泥上滩使得横沙东滩淤长速度显著加快。 相似文献
18.
Hydrodynamics of the Bottom-Water Flow from the Arctic to the Atlantic through the Strait of Denmark
Morozov E. G. Frey D. I. Gladyshev S. V. Gladyshev V. S. 《Izvestiya Atmospheric and Oceanic Physics》2020,56(5):479-487
Izvestiya, Atmospheric and Oceanic Physics - The overflow of bottom waters through the Strait of Denmark to the Atlantic has been investigated. A unique physical and hydrodynamic effect of... 相似文献
19.
Putting the principles of the Sustainable Livelihoods Approach into fisheries development policy and practice 总被引：1，自引：1，他引：1
The Sustainable Livelihoods Approach (SLA) combines a conceptual framework with a set of operational principles to provide guidance on policy formulation and development practice. The SLA has been widely used in coastal and fisheries development research and has informed the design of development programmes but experience of operationalising it remains largely undocumented. In the Sustainable Fisheries Livelihoods Programme, which involves 25 West African countries, the SLA has helped to align fisheries policy with wider poverty reduction initiatives and to identify means of contributing to poverty reduction that do not directly increase pressure on fully or over-exploited fish resources. 相似文献
20.
Tullio Treves 《Marine Policy》1981,5(3):273-276
The Drafting Committee of UNCLOS has encountered severe difficulties. Drafting problems derive from the presence in the Draft Convention of different layers of language originating from various sources, such as the Geneva and IMCO Conventions. An entirely new procedure has been adopted by the Drafting Committee to overcome the difficulties. This procedure is based on the work of six ‘language groups’ and their coordinators. 相似文献