Probable gas hydrate/free gas model over western continental margin of India     

Satyavani  N.  Shankar  Uma  Thakur  N.K.  Reddi  S.I. 《Marine Geophysical Researches》2002,23(5-6):423-430

Multi-channel seismic reflection data from the western continental margin of India (WCMI) have been analyzed to construct a plausible model for gas hydrate formation. A reflector at 2950 ms two way travel time (TWT) on one of the sections is interpreted to represent the base of the layer of the methane hydrate, identified by a bottom simulating reflector (BSR) that lies almost 500 ms beneath the sea floor. BSRs of similar origin are common world wide, where they are usually interpreted to mark the base of gas hydrate bearing clastic sediment, with or without underlying free gas. In this study we present a model with the contrasting physical properties that produce synthetic wavelets that match with the observed BSR amplitude and waveforms for varying source-receiver offsets of multi-channel seismic reflection data. The preliminary results presented here put important constraints on models that predict the distribution and formation of hydrate. Offset-dependent amplitude recovery also gives an appropriate response for hydrate characterization.  相似文献   

印度东南部海岸拉梅斯沃勒姆滨外保克湾底层水特征对底栖有孔虫的影响     

Kumar V  高莉玲 《海洋地质前沿》2001,17(12):13-15

有孔虫生活在海洋和半咸水环境。底栖有孔虫的存在很大程度上受物理因素（深度、温度、光量、水体扰动）、化学因素（盐度、溶解氧和可用元素）和生物因素（食物供给量和底层沉积物特征）的制约。研究人员对印度东、西岸现代底栖有孔虫生态学和分布状态进行了研究。Ｎａｉｄｕ等在对Ｖｉｓａｋｈａｐａｔｎａｍ港复合体有孔虫进行分析后提出 ,可以将有孔虫作为海洋污染的指示物。ＳｒｅｅｎｉｖａｓａＲａｏ等采用Ｑ模式系数分析对尼赞伯德讷姆湾有孔虫的分布进行了研究 ,确认此区域存在４种组合 ,受不同环境条件的影响。Ｋｈａｒｅ等对门格…  相似文献   

Hydrodynamic characteristics of floating toroidal bodies     

S.A. Mavrakos 《Ocean Engineering》1997,24(4):381-399

The paper deals with the linearized exciting wave forces and hydrodynamic coefficients of a toroidal body floating in water of finite depth. For the solution of the diffraction and the radiation problems the flow field around the body is subdivided into ring-shaped fluid regions, in each of which axisymmetric eigenfunction expansions for the velocity potential is made. By implementing Galerkin's method the various potential solutions are matched and numerical results concerning the exciting wave forces and the hydrodynamic coefficients in all modes of motion are obtained.  相似文献   

New models for the exploration of biological processes at fronts     

Franks  Peter J. S. 《ICES Journal of Marine Science》1997,54(2):161-167

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The responses of some estuarine organisms to heavy metals applied under various experimental conditions     

N.V. Jones  R.F. Uglow 《Marine environmental research》1985,17(2-4)

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Wave forces on a single and on a group of cylinders in response to two wave spectra of same significant wave height     

S. Meenakshi Sundaram  C. K. Madheswaran 《Ocean Engineering》1991,18(4)

Spectral analysis is used to determine the wave force characteristics on structures exposed to random waves. Considerable work has been carried out to determine the magnitude of random wave forces acting on a single cylinder, but little information is available in the case of a group of cylinders in random waves. Such situations arise when structures comprise multiple tubular members which are in close proximity, and wave forces cannot be calculated precisely by analytical methods due to complicated flow conditions past the group. Experimental studies are also required for proper understanding and analysis. An experimental scheme was carried out to study the wave force characteristics on a single cylinder and on a group of cylinders in response to two different wave spectra with the same significant wave height, and the results are compared.  相似文献   

Raising the packing density of computerized oceanographic data records     

V. V. Dolotov  L. V. Eremeeva 《Physical Oceanography》1995,6(3):237-239

In this paper the peculiarities of compiled oceanographic data sets, which consist primarily in the presence of some characteristic information as well as in the planned incomplete filling of the files with observations, are discussed. A number of special ways are suggested which essentially improve the packing density of computerized data without applying special archiving algorithms. The effectiveness of these methods has been tested by treating thein situ hydrological/chemical data file compiled in the Black Sea in 1988.Translated by Vladimir A. Puchkin.  相似文献   

Relationship between the anomalies of temperature and air pressure over the ocean     

S. G. Boguslavsky  S. I. Kazakov  Yu. P. Krasovsky 《Physical Oceanography》1994,5(5):359-367

This paper considers the relationship between multi-year air temperature and pressure fluctuations over the ocean, based on an approximate solution of the problem on the determination of large-scale seawater temperature anomalies from the conditions predominating at the sea surface. The dependence derived is numerically analysed using observations made in the North Atlantic. It is shown that the variability of annual mean air temperature anomalies is largely controlled by the air pressure field which has taken place during the preceding long-term period. The dependence derived may be applied to generate long-term forecasts of the ocean's hydrometeorological regime.Translated by Vladimir A. Puchkin.  相似文献   

Modification of a seasonally oscillating growth function for use with mark-recapture data     

Appeldoorn  Richard S. 《ICES Journal of Marine Science》1987,43(3):194-198

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Some General Properties of Transverse Motions of the Geostrophic Front     

Dotsenko  S. F.  Rubino  A.  Brandt  P. 《Physical Oceanography》2003,13(4):189-200

Within the framework of the reduced-gravity model of the ocean taking into account the effect of friction in the Rayleigh form, we study the two-dimensional problem of nonlinear motions of a subsurface front of finite width. We consider the conservation laws and the character of motion of the center-of-mass of the cross section of the front and their variations caused by the losses of energy. For fields with special structure, the problem is reduced to the solution of a system of nonlinear ordinary differential equations. It is shown that the initially geostrophic frontal current decays with time according to a power law. The deviations of the initial state of the front from the state of geostrophic balance result in the generation of superinertial oscillations of the hydrodynamic fields.  相似文献