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   

Outer wave number spectrum and statistical distribution of apparent wave number vector     

J. -B. Song  K. -J. Wu  Y. -H. Wu 《Ocean Engineering》2003,30(3):401-412

Based on the ray theory and Longuet-Higgins’s linear model of sea waves, the joint distribution of wave envelope and apparent wave number vector is established. From the joint distribution, we define a new concept, namely the outer wave number spectrum, to describe the outer characteristics of ocean waves. The analytical form of the outer wave number spectrum, the probability distributions of the apparent wave number vector and its components are then derived. The outer wave number spectrum is compared with the inner wave number spectrum for the average status of wind-wave development corresponding to a peakness factor P = 3. Discussions on the similarity and difference between the outer wave number spectrum and inner one are also presented in the paper.  相似文献   

Environmental impact of chemical wastes produced by the salmon aquaculture industry   总被引：1，自引：0，他引：1  

Haya  K.; Burridge  L. E.; Chang  B. D. 《ICES Journal of Marine Science》2001,58(2):492-496

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Modelling the timing of plankton production and its effect on recruitment of cod (Gadus morhua)     

Brander  K. M.; Dickson  R. R.; Shepherd  J. G. 《ICES Journal of Marine Science》2001,58(5):962-966

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Imbalance in the carbonate budget of surficial sediments in the North Atlantic Ocean: variations over the last millenium?     

C. Rabouille  H. Stahl  F. Bassinot  A. Tengberg  J. Brunnegard  P. Hall  K. Kiriakoulakis  J. -L. Reyss  L. Dezileau  P. Crassous  P. Roos  R. S. Lampitt 《Progress in Oceanography》2001,50(1-4)

Fluxes contributing to the particulate carbonate system in deep-sea sediments were investigated at the BENGAL site in the Porcupine Abyssal Plain (Northeast Atlantic). Deposition fluxes were estimated using sediment traps at a nominal depth of 3000 m and amounted to 0.37±0.1 mmol C m⁻² d⁻¹. Dissolution of carbonate was determined using flux of total alkalinity from in situ benthic chambers, is 0.4±0.1 mmol C m⁻² d⁻¹. Burial of carbonate was calculated from data on the carbonate content of the sediment and sedimentation rates from a model age based on ¹⁴C dating on foraminifera (0.66±0.1 mmol C m⁻² d⁻¹). Burial plus dissolution was three times larger than particle deposition flux which indicates that steady-state is not achieved in these sediments. Mass balances for other components (BSi, ²¹⁰Pb), and calculations of the focusing factor using ²³⁰Th, show that lateral inputs play only a minor role in this imbalance. Decadal variations of annual particle fluxes are also within the uncertainty of our average. Long-term change in dissolution may contribute to the imbalance, but can not be the main reason because burial alone is greater than the input flux. The observed imbalance is thus the consequence of a large change of carbonate input flux which has occured in the recent past. A box model is used to check the response time of the solid carbonate system in these sediments and the time to reach a new steady-state is in the order of 3 kyr. Thus it is likely that the system has been perturbed recently and that large dissolution and burial rates reflect the previously larger particulate carbonate deposition rates. We estimate that particulate carbonate fluxes have certainly decreased by a factor of at least 3 and that this change has occurred during the last few centuries.  相似文献   

A New Methodology for Incorporating Tide Gauge Data in Sea Surface Topography Models   总被引：1，自引：0，他引：1  

J. C. Iliffe  M. K. Ziebart  J. F. Turner 《Marine Geodesy》2007,30(4):271-296

As part of the Vertical Offshore Reference Frames (VORF) project sponsored by the U. K. Hydrographic Office, a new model for Sea Surface Topography (SST) around the British Isles has been developed. For offshore areas (greater than 30 km from the coast), this model is largely derived from satellite altimetry. However, its accuracy and level of detail have been enhanced in coastal areas by the inclusion of not only the 60 PSMSL tide gauges with long-term records around the coasts of the United Kingdom and Ireland but also some 385 gauges established at different epochs and for different observation spans by the U. K. Admiralty. All tide gauge data were brought into a common reference frame by a combination of datum models and direct GPS observations, but a more significant challenge was to bring all short-term sea level observations to an unbiased value at a common epoch. This was achieved through developing a spatial-temporal correlation model for the variations in mean sea level around the British Isles, which in turn meant that gauges with long-term observation spans could be used as control points to improve the accuracy of Admiralty gauges. It is demonstrated that the latter can contribute point observations of mean sea level (MSL) with a precision of 0.078 m. A combination of least squares collocation and interpolation was developed to merge the coastal point and offshore gridded data sets, with particular algorithms having to be developed for different configurations of coastal topology. The resulting model of sea surface topography is shown to present a smooth transition from inshore coastal areas to offshore zones. Further benefits of the techniques developed include an enhanced methodology for detecting datum discontinuities at permanent tide gauges.  相似文献   

Effect of ice cover on oscillations of fluid in a closed basin   总被引：1，自引：0，他引：1  

I. V. Sturova 《Izvestiya Atmospheric and Oceanic Physics》2007,43(1):112-118

Within the framework of the linear theory of long waves, the problem of the effect of ice cover on seiche oscillations of fluid in a two-dimensional constant-depth basin is solved. The eigenfrequencies and eigenfunctions of seiche oscillations are obtained for different boundary conditions at ice edges: rigid coupling and free edges. The forced oscillations of fluid and ice under the action of a moving disturbance of atmospheric pressure are investigated. The change in the stress of ice bending is considered and it is shown that the coast ice can be broken.  相似文献   

Numerical simulation of convective clouds developing in the atmosphere in emergency situations (explosions,fires)     

N. E. Veremei  Yu. A. Dovgalyuk  E. N. Stankova 《Izvestiya Atmospheric and Oceanic Physics》2007,43(6):731-744

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Variations in the sedimentation in Kara Bogaz Gol Bay related to sea level fluctuations during the Novocaspian time     

Yu. A. Karpychev 《Oceanology》2007,47(6):857-864

The structure of the bottom sediments in Kara Bogaz Gol Bay is correlated with the history of the sea level fluctuations in the Caspian Sea during the Novocaspian time based on the radiocarbon geochronology of the coastal and bottom sediments. Instrumental observations of the sea level and the hydrochemical regime of the bay are considered to substantiate the correlations obtained.  相似文献