辽东湾地区下第三系地震速度—岩性预测模型研究   总被引：9，自引：1，他引：9  

刘震  高先志 《海洋地质与第四纪地质》1993,13(4):25-34

地震速度－岩性预测模型由四个子模型组成：即（１）砂泥岩压实模型；（２）地震层速度转换模型；（３）速度校正模型；（４）砂岩指数转换模型。辽东湾地区的实际资料证明，上述四个子模型不但决定了岩性预测的具体方法，而且严格控制岩性预测的精度。  相似文献   

Wave Defending Effects of V-Type Bottom-Mounted Breakwaters     

缪国平程建生  龙云祥王景全 《中国海洋工程》2005,19(2):195-204

An analytical method is developed for the study of the wave defending effects of the V-type bottom-mounted breakwater. The breakwater is assumed to be rigid, thin, impermeable and vertically located in water of constant depth. The fluid domain is divided into three sub-regions by an imaginary interface. The velocity potential in each region is expanded by eigenfunctions. By satisfying the corresponding boundary conditions and matching conditions in and between sub-regions, a set of hnear algebraic equations can be obtained to determine the unknown coetfficients for the eigenfunction expansions for each sub-region. The accuracy of the present model is verified by a comparison with existing results for the case of an isolated breakwater. Numerical results, in the form of contour maps of the relative wave amplitude around the breakwater, are presented for a range of wave and breakwater parameters. The results show that the V-type bottommounted breakwater is generally effective in defending against waves. In general, the wave height in the protected area is about 20-50 percent of the incident wave height.  相似文献   

Experiments on the discrimination of fish and seabed echoes     

MacLennan  D.N.; Copland  P.J.; Armstrong  E.; Simmonds  E.J. 《ICES Journal of Marine Science》2004,61(2):201-210

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Air-Sea Gas Transfer Velocity in Stormy Winter Estimated from Radon Deficiency     

Hitoshi Kawabata  Hisashi Narita  Koh Harada  Shizuo Tsunogai  Masashi Kusakabe 《Journal of Oceanography》2003,59(5):651-661

Thirteen vertical profiles of ²²⁶Ra and ²²²Rn in the near-surface water were obtained in the western North Pacific in winter, and the gas transfer velocities across the air-sea interface were estimated. The transfer velocities found by applying a steady state model varied widely from 2.1 to 30.2 m day⁻¹ with a mean of 9.4 m day⁻¹. The mean value is almost 5 times higher than that in summer in other oceans, and the maximum value is a record high for world oceans. This is partly due to the inadequacy of the steady state model, which overestimates when stronger winds blow in more recent days than the ²²²Rn half-life of about 4 days. In fact, a strong low pressure zone passed through the station about 2 days earlier, which was one of the low pressure zones that with a period of develop once a week or so in the northwestern North Pacific in winter. Instead of steady-state removal, if half of the radon removal occurred sporadically every 7 days, and the last removal took place two days before the observation, the transfer velocity would be 26 m day⁻¹. Our mean transfer velocity, which is less than 20% different from the steady state value including both overestimated and underestimated values, 9.4 ± 4.8 m day⁻¹, seems to represent the mean state of this region in winter. This suggests that the gas exchange fluxes under extremely rough conditions in the open ocean are larger than those estimated by using a transfer velocity equation with a linear or quadratic relationship with wind speed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Correction method for full-depth current velocity with lowered acoustic Doppler current profiler (LADCP)   总被引：1，自引：0，他引：1  

Kanae Komaki  Masaki Kawabe 《Journal of Oceanography》2007,63(6):995-1007

A new method is presented to process and correct full-depth current velocity data obtained from a lowered acoustic Doppler current profiler (LADCP). The analysis shows that, except near the surface, the echo intensity of a reflected sound pulse is closely correlated with the magnitude of the difference in vertical shear of velocity between downcast and upcast, indicating an error in velocity shear. The present method features the use of echo intensity for the correction of velocity shear. The correction values are determined as to fit LADCP velocity to shipboard ADCP (SADCP) and LADCP bottom-tracked velocities. The method is as follows. Initially, a profile of velocity relative to the sea surface is obtained by integrating vertical shears of velocity after low-quality data are rejected. Second, the relative velocity is fitted to the velocity at 100–800 dbar measured by SADCP to obtain an “absolute” velocity profile. Third, the velocity shear is corrected using the relationship between the errors in velocity shears and echo intensity, in order to adjust the velocity at sea bottom to the bottom-tracked velocity measured by LADCP. Finally, the velocity profile is obtained from the SADCP-fitted velocity at depths less than 800 dbar and the corrected velocity shear at depths greater than 800 dbar. This method is valid for a full-depth LADCP cast throughout which the echo intensity is relatively high (greater than 75 dB in the present analysis). Although the processed velocity may include errors of 1–2 cm s⁻¹, this method produced qualitatively good current structures in the Northeast Pacific Basin that were consistent with the deep current structures inferred from silicate distribution, and the averaged velocities were significantly different from those calculated by the Visbeck (2002) method.  相似文献   

Comparison of equal-area cylindrical and circular piston transducers     

Foote  Kenneth G. 《ICES Journal of Marine Science》1995,52(1):67-75

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Types and characters of sub-bottom acoustic reflection in eastern part of Bohai Sea     

Wang Kuiyang  Liu Zhenxi  Xia Dongxing 《海洋学报(英文版)》1997,16(2):225-237

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Material properties of North Atlantic cod eggs and early-stage larvae and their influence on acoustic scattering   总被引：1，自引：2，他引：1  

Chu  Dezhang; Wiebe  Peter H.; Copley  Nancy J.; Lawson  Gareth L.; Puvanendran  Velmurugu 《ICES Journal of Marine Science》2003,60(3):508-515

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SSA1—1型声学水位在长江口潮位站的应用     

万里明 《台湾海峡》1996,15(2):210-214

本文介绍了长江口区水文泥沙概况，举例说明了ＳＳＡ１－１型声水位计在崇头潮位站比测试验和投产应用情况，结果表明该水位计是收集长江口区潮位资料较理想的仪器。  相似文献   

Dereverberation of marine reflection seismic data by a spatial combination of predictive deconvolution and velocity filtering     

C. Samson  G. F. West 《Marine Geophysical Researches》1995,17(1):1-15

Contamination of seismic reflection records at early times by first-order water reverberations can be especially severe during survey operations over hard and flat sea floors on the continental shelf or in lake environments. A new dereverberation scheme based on two classical techniques — predictive deconvolution and velocity filtering — has been developed to address this problem. The techniques are combined spatially to take advantage of their complementary offset- and time-dependent properties. Stage I of the scheme consists of applying predictive deconvolution at short offset. The data are previously conditioned by a normal moveout correction with the water velocity which restores the periodicity of the reverberations in the offset-time plane and enhances the performance of deconvolution. Stage II of the scheme involves velocity filtering in the common-midpoint domain which is particularly effective at long offset where the moveout difference between primary reflections and reverberations is largest. The dereverberation scheme is well suited for the initial processing of large volumes of data due to the general availability of cost-effective deconvolution and velocity filtering algorithms in seismic processing software packages. Practical implementation issues are illustrated by a field example from the GLIMPCE survey in Lake Superior.Lithoprobe Publication No. 475.  相似文献