共查询到20条相似文献，搜索用时 218 毫秒
1.
Instability analysis of three-dimensional ocean shear waves 总被引：1，自引：0，他引：1
Qiao Fangli 《海洋学报(英文版)》1996,15(1):1-8
Ｉｎｓｔａｂｉｌｉｔｙａｎａｌｙｓｉｓｏｆｔｈｒｅｅ－ｄｉｍｅｎｓｉｏｎａｌｏｃｅａｎｓｈｅａｒｗａｖｅｓ￥ＱｉａｏＦａｎｇｌｉ（ＲｅｃｅｉｖｅｄＮｏｖｅｍｂｅｒ６，１９９５，ａｃｃｅｐｔｅｄＮｏｖｅｍｂｅｒ３０．１９９５）Ａｂｓｔｒａｃｔ：Ｂａｓｅ... 相似文献
2.
The application of Hartley transform to ocean engineering 总被引：1，自引：0，他引：1
The Hartley transform is a real integral transform based on harmonic functions and hassome characteristics similar to the Fourier transform. Most applications in ocean engineering requiring the Fourier transform can also be performed by the Hartley transform. The fast Hartley transform is twice faster and more convenient to handle than the corresponding fast Fourier transform, so it is a real valued alternative to the complex Fourier transform in many applications. The use of the Hartley transform in ocean engineering is presented in detail in this paper, including wave spectral analysis, separation of waves, cross-correlation in PIV technique and expression of equation in the Hartley domain. The examples in the paper show deeply the advantage and efficiency of the Hartley transform over the Fourier transform. 相似文献
3.
《Ocean Modelling》2002,4(2):137-172
A new sea ice model, GELATO, was developed at Centre National de Recherches Météorologiques (CNRM) and coupled with OPA global ocean model. The sea ice model includes elastic–viscous–plastic rheology, redistribution of ice floes of different thicknesses, and it also takes into account leads, snow cover and snow ice formation. Climatologies of atmospheric surface parameters are used to perform a 20-year global ocean–sea ice simulation, in order to compute surface heat fluxes from diagnosed sea ice or ocean surface temperature. A surface salinity restoring term is applied only to ocean grid cells with no sea ice to avoid significant surface salinity drifts, but no correction of sea surface temperature is introduced. In the Arctic the use of an ocean model substantially improves the representation of sea ice, and particularly of the ice edge in all seasons, as advection of heat and salt can be more accurately accounted for than in the case of, for example, a sea ice–ocean mixed layer model. In contrast, in the Antarctic, a region where ocean convective processes bear a much stronger influence in shaping sea ice characteristics, a better representation of convection and probably of sea ice (for example, of frazil sea ice, brine rejection) would be needed to improve the simulation of the annual cycle of the sea ice cover. The effect of the inclusion of several ice categories in the sea ice model is assessed by running a sensitivity experiment in which only one category of sea ice is considered, along with leads. In the Arctic, such an experiment clearly shows that a multicategory sea ice model better captures the position of the sea ice edge and yields much more realistic sea ice concentrations in most of the region, which is in agreement with results from Bitz et al. [J. Geophys. Res. 106 (C2) (2001) 2441–2463]. 相似文献
4.
A simulation of radiation imagery for ocean color satellite 总被引：2，自引：0，他引：2
The ocean color satellite is mainly applied to measure the water constituents such as chlorophyll, suspended material and yellow substance. The leaving water radiance is very small part of the total radiance arrival at the sensor about 3%-15%,and depends on the properties of the orbit and sensor. Before the satellite is launched on the orbit, it needs to simulate the radiation imagery in order to evaluate the quality and availability of the satellite data.
If the parameters of satellite orbit, the properties of sensor as well as the characteristics of the atmosphere and water have been known, the radiation scattered by air molecule and aerosol, reflected solar radiation, water leaving and total radiation arriving at the sensor can be simulated by the models of radiation transfer in the atmosphere, air/water and subsurface water. In this paper, the mechanism, models and procedures of the radiation simulation are first discussed and employed to simulate a series of imageries for the Chinese satellites FY-lA, FY-1B, and ROCSAT-1 (Taiwan, China), and American satellite Ses STAR. Their results show that the solar irradiance arrived at water surface and the sun glitter mainly affect the quality and availability of satellite data, which depend on the orbit properties. Finally, some suggestions are proposed to improve the quality and availability of a:ean color satellite data. 相似文献
If the parameters of satellite orbit, the properties of sensor as well as the characteristics of the atmosphere and water have been known, the radiation scattered by air molecule and aerosol, reflected solar radiation, water leaving and total radiation arriving at the sensor can be simulated by the models of radiation transfer in the atmosphere, air/water and subsurface water. In this paper, the mechanism, models and procedures of the radiation simulation are first discussed and employed to simulate a series of imageries for the Chinese satellites FY-lA, FY-1B, and ROCSAT-1 (Taiwan, China), and American satellite Ses STAR. Their results show that the solar irradiance arrived at water surface and the sun glitter mainly affect the quality and availability of satellite data, which depend on the orbit properties. Finally, some suggestions are proposed to improve the quality and availability of a:ean color satellite data. 相似文献
5.
An operational satellite remote sensing system for ocean fishery 总被引：3，自引：0，他引：3
Ocean environmental information is very important to supporting the fishermen in fishing and satellite remote sensing technology can provide it in large scale and in near real-time. Ocean fishery locations are always far away beyond the coverage of the satellite data received by a land-based satellite receiving station. A nice idea is to install the satellite ground station on a fishing boat. When the boat moves to a fishery location, the station can receive the satellite data to cover the fishery areas. One satellite remote sensing system was once installed in a fishing boat and served fishing in the North Pacific fishery areas when the boat stayed there. The system can provide some oceanic environmental charts such as sea surface temperature (SST) and relevant derived products which are in most popular use in fishery industry. The accuracy of SST is the most important and affects the performance of the operational system, which is found to be dissatisfactory. Many factors affect the accuracy of SST and it is difficult to increase the accuracy by SST retrieval algorithms and clouds detection technology. A new technology of temperature error control is developed to detect the abnormity of satellite-measured SST. The performance of the technology is evaluated to change the temperature bias from-3.04 to 0.05 ℃ and the root mean square (RMS) from 5.71 to 1.75 ℃. It is suitable for employing in an operational satellite-measured SST system and improves the performance of the system in fishery applications. The system has been running for 3 a and proved to be very useful in fishing. It can help to locate the candidates of the fishery areas and monitor the typhoon which is very dangerous to the safety of fishing boats. 相似文献
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Abstract The wave‐induced cyclic shear stresses in ocean‐floor sands may cause a progressive buildup of pore water pressure, leading to instability of the bed. This instability may constitute an important consideration in the analysis and design of various offshore engineering facilities. This paper presents a general procedure for the analysis of pore water pressure in the ocean‐floor sands under the action of random waves. Using a simple linear model for the generation of pore water pressure and incorporating the effect of its simultaneous dissipation, a formulation for the expected damage associated with buildup of pore pressure is developed in a stochastic framework. Numerical results of an example analysis are also presented. 相似文献
8.
A 5’ detailed gravimetric geoid has been computed for the northwest Atlantic Ocean as ground truth for the GEOS‐3 satellite altimeter experiment. Comparisons of this geoid with satellite derived geoceiver station heights show an r.m.s. difference of 1.2 m. Initial comparisons with GEOS‐III altimeter derived geoid profiles have indicated a relative agreement of generally better than 2 m. 相似文献
9.
Zhang Huai 《海洋学报(英文版)》1988,7(4):514-520
The paper studies the short period response of an unbounded and uniform ocean to moving wind field. Firstly, it is shown that the response disturbance has two kinds of motion, one is geostrophical and other is inertial gravity wave. Secondly, this paper studies the disturbance source caused by a circular wind field which moves rapidly in a straight path on a horizontal plane. It is shown that the disturbance source is mainly determined by the distribution of the curl of wind stress. Thirdly, this paper studies the solution of disturbance equation with nonhomogeous term of disturbance source as an impulse. It is shown that the oceanic response is determined by disturbance source. Finally, by calculating numerically the current velocity and surface elevation in time, it is shown that the intensity, spatial scale and duration of the response are closely related to wind field. 相似文献
10.
Ｍａｘｉｍｕｍｅｎｔｒｏｐｙｐｒｉｎｃｉｐｌｅａｎｄｓｔａｔｉｓｔｉｃａｌｄｉｓｔｒｉｂｕｔｉｏｎｏｆｏｃｅａｎｗａｖｅｈｅｉｇｈｔｓ￥ＷｕＫｅｊｉａｎａｎｄＳｕｎＦｕ（ＲｅｃｅｉｖｅｄＭａｙ１５，１９９５；ａｃｃｅｐｔｅｄＪｕｎｅ２１，１９９５）Ａ... 相似文献
11.
A technique is currently under development a the Naval Research Laboratory for imaging of backscatterec acoustic returns from ocean basin topography. The method is straightforward. An explosive sound source is detonated near the center of an ocean basin and the round‐trip travel time from source to reflectors and return is measured. Distance to back‐scattering topography is assumed to be proportional to round‐trip time, with a proportionality constant equal to half the sound speed. A multielement receiving array is used to determine the azimuthal directions to topographic features. Reverberation data are output to an imaging system to study the spatial distribution of sea bottom reverberation. The images are in the form of two‐dimensional maps of backscattered acoustic energy. Typical maps are larger than 2,000 km x 2,000 km (or area coverage greater than 4 x 106 km2). After correction of maps from individual shot detonations for range‐dependent propagation losses, we average ("integrate") maps together on a pixel by pixel basis for a clear picture of major basin reverberators. 相似文献
12.
A long-term warming pattern of global subsurface ocean was detected separately from other natural variations. Three dominant modes were extracted: a long-term warming mode, a mode related to the El Niño/Southern Oscillation, and a mode related to the Atlantic Multidecadal Oscillation. The long-term warming mode explained 78 % of the global mean temperature variance from the surface to a depth of 300 m, and the other two modes could explain most of the residual variance. Subsurface warming associated with the long-term warming mode was strong in the subtropics. In contrast, there was a local minimum of warming in the northern hemisphere subarctic ocean, and warming was suppressed in subsurface waters south of the equator. Atmospheric changes associated with the long-term warming mode showed negative (positive) sea level pressure anomalies at high (middle) latitudes in both hemispheres, and an intensification and/or a poleward expansion of mid-latitude westerlies. Wind stress curl changes were negative in the subtropics and positive in the subarctic of the northern hemisphere; changes that were consistent with the strong warming in the subtropics and the local minimum of warming in the subarctic. Warming of Southern Ocean subsurface waters coincided with southward migration and intensification of westerly winds, whereas surface warming to the south of 50°S was suppressed, probably by strengthened northward Ekman transport. Positive wind stress curl off the equator with weakening of the tropical easterly winds in the Pacific and Indian Oceans was consistent with the subsurface negative temperature anomaly there. 相似文献
13.
Qiao Fangli 《海洋学报(英文版)》1996,15(2):145-158
Ｔｈｅｍｉｘｉｎｇｍｅｃｈａｎｉｓｍｉｎｔｈｅｆｏｒｍａｔｉｏｎｏｆｏｃｅａｎｓｈｅａｒｗａｖｅｓ￥ＱｉａｏＦａｎｇｌｉ（ＦｉｒｓｔＩｎｓｔｉｔｕｔｅｏｆＯｃｅａｎｏｇｒａｐｈｙ，ＳｔａｔｅｏｃｅａｎｉｃＡｄｍｉｎｉｓｔｒａｔｉｏｎ，Ｑｉｎｇｄａｏ２... 相似文献
14.
1 IwrRODUcrIONIt is necessary to understand disastrous weather systems as the activities of exploitingand uti1izing marine resources, especialIy for the needs of navigation and oil-gas prospecting.Typhoon is the most frequent and dangerous disastrous weather system in summer-autumnseason in the Nolthwest Pacific Ocean. The explosive cyclogenesis developing quickly overocean is the most terrible weather system in winteL The explosive cycnogenesis grows fastwith high intensity of violent wi… 相似文献
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ＲＥＥｄｉｓｔｒｉｂｕｔｉｏｎｉｎｗａｔｅｒ－ｓｅｄｉｍｅｎｔｉｎｔｅｒｆａｃｅｓｙｓｔｅｍａｔｄｅｅｐｏｃｅａｎｆｌｏｏｒ￥ＺｈａｎｇＬｉｊｉｅ；ＬｉｕＪｉｈｕａａｎｄＹａｏＤｅ（ＲｅｃｅｉｖｅｄＦｅｂｒｕａｒｙ１，１９９４；ａｃｃｅｐｔｅｄＭａｙ... 相似文献
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The data of beam propagation of internal waves into the ocean are confirmed by several analytical solutions of the linear
long wave theory. The obtained solutions are applied to calculate the mode of the internal waves. 相似文献
18.
ＮｕｍｅｒｉｃａｌｓｉｍｕｌａｔｉｏｎｏｆｔｈｅｕｐｐｅｒｏｃｅａｎｃｕｒｒｅｎｔｓｉｎＳｏｕｔｈＣｈｉｎａＳｅａ￥ＬｉＲｏｎｇｆｅｎｇ；ＨｕａｎｇＱｉｚｈｏｕａｎｄＷａｎｇＷｅｎｚｈｉ（ＩｎｓｔｉｔｕｔｅｏｆＡｔｍｏｓｐｈｅｒｉｃＰｈｙｓｉｃｓ，Ｃ... 相似文献
19.
Wave–current flow is a phenomenon that is present in many practical engineering situations. Over the past several decades, this type of flow has been increasingly investigated under controlled laboratory conditions. This paper presents a numerical study of wave–current flow in the ocean basin of the LabOceano (COPPE/UFRJ). A homogeneous multiphase model based on the RANS equations and the k–ɛ turbulence model implemented in ANSYS-CFX code were used. A cross section of the ocean basin was represented. A regular wave with a height of 0.08 m and a period of 1.80 s (i.e., a wave steepness of H/L = 0.016), propagating on favourable currents, was simulated. The behaviour of the free surface elevation over time and the streamlines along the basin for wave and wave–current flows were presented. The numerical results were compared to the non-viscous theory given by the Rayleigh equation applied to the problem of wave–current interaction. Good agreement was found between the wave length estimated by the numerical results and the analytical solutions, with a deviation of less than 2%. 相似文献
20.
《Ocean Modelling》2003,5(2):157-170
Model results from a regional model (BRIOS) of the Southern Ocean that includes ice shelf cavities and the interaction between ocean and ice shelves are used to derive a simple parameterization for ice shelf melting and the corresponding fresh water flux in large-scale ocean climate models. The parameterization assumes that the heat loss and fresh water gain due to the ice shelves are proportional to the difference in freezing temperature at the ice shelf edge base and the oceanic temperature on the shelf/slope area of the adjacent ocean as well as an effective area of interaction. This area is proportional to the along-shelf width of ice shelf and an effective cross-shelf distance, which turns out to be rather uniform (5–15 km) for a variety of different ice shelves. The proposed parameterization is easy to implement and valid for a wide range of circumstances. An application of the proposed scheme in a global ice ocean model (CLIO) supports our hypothesis that it can be used successfully and improves both the ocean and sea ice component of the model. This parameterization should also be used in models of the climate system that include a coupling between an ice sheet and an oceanic component. 相似文献