共查询到19条相似文献，搜索用时 125 毫秒
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海洋测深的波束角效应及其改正 总被引：11，自引：6，他引：5
测深仪波束角效应使记录的测深图像(海底地形)产生变形,本文将测深仪波束角效应分为三种:时移效应;双曲线增伪丢失效应;深度丢失效应。并对这三种效应进行了分析研究,提出了改正方法,不同类型海底地形的数值试验结果证实了该方法的有效性,该方法可极大地提高海洋测深的精度和可靠性。 相似文献
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海洋测深中时移和偏移效应综合分析与改正 总被引：2，自引：2，他引：2
海洋测深中，定位与测深分属两个独立的技术系统，测深时两系统在时间和空间上难以保持一致，从而存在匹配误差。本文着重论证了产生匹配误差的两种因素(延时效应和定位中心与测深中心的偏移效应)之间的关系及其对测深结果的综合影响，最后给出了各种情况下匹配误差的改正方法。数值实验结果表明该算法的有效性。 相似文献
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海洋测深中的波浪效应改正技术 总被引：3，自引：5，他引：3
以GPS海洋测量手段为代表的现代海洋测量技术已经形成,海洋测量的测深、定位两大主题已得到较好的解决。但是,海洋水深测量数据的改正和归算理论与方法还需要进一步改进。本文对海洋测深中的波浪效应问题进行探讨,提出了波浪效应改正技术,为提高精密海底信息场测量与表征的精度,建立了海洋水深测量数据的改正和归算问题中由波浪效应引起的相关测深改正的数学模型。 相似文献
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This paper derives the explicit expressions for the average intensity, beam width and angular spread of Gaussian Schell-model (GSM) beams with edge dislocation propagating through atmospheric turbulence along a slant path. The propagation of GSM beams with edge dislocation through horizontal atmospheric turbulence can be treated as a special case through a slant one. The propagation properties of GSM beams with edge dislocation through slant atmospheric turbulence are studied, where the influence of edge dislocation parameters including the slope p and off-axis distance d on the spreading of GSM beams with edge dislocation in atmospheric turbulence is stressed. It shows that the spreading of the intensity profile of GSM beams with edge dislocation along a slant path is smaller than that along a horizontal path in the long-distance atmospheric propagation. The larger the slope vert pvert and the smaller the off-axis distance vert dvert are, the less the beam-width spreading and angular spread of GSM beams with edge dislocation are affected by turbulence. The GSM beams with edge dislocation is less affected by turbulence than that of GSM beams without edge dislocation. The results are illustrated numerically and their validity is interpreted physically. 相似文献
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Hydroacoustic methods are particularly suitable for investigations of the occurrence, cyclicity and amount of bubbles released at cold seeps without disturbing them. Experiments with a horizontally looking single beam transducer (40 and 300 kHz) directed towards artificially produced bubbles show that the backscattering strength of the bubbles increases with the gas flux rate independently of the bubble radii distribution. It is demonstrated that an acoustic system can be calibrated in such a way that gas flux rates of bubble-size spectra, as observed at natural seeps, can be directly related to the echo level of a known, acoustically insonified volume. No system-specific parameters have to be known except the beam width. 相似文献
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基于浮标站海浪历史数据,利用回归分析方法建立了海浪数值模式有效波高预报产品的一元二次回归方程订正统计模型。通过2017年7月1日-2018年10月10日期间业务试运行结果发现:订正方程能有效改善有效波高数值预报产品的预报精度,且预报时效越短订正效果越显著。其中,第6~11 h预报时效内的订正前后平均绝对误差值减小0.17~0. 241 m,第6~18 h预报时效内订正前后均方根误差减小幅度为0.103~0. 28 m。这说明应用订正统计模型对海浪模式输出产品进行订正,也是改进海浪模式预报准确率的一种有效途径。 相似文献
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There are rich natural gas resources in the northwestern South China Sea deepwater areas, with poor degree of exploration. Because of the unique tectonic, sedimentary background of the region, velocity... 相似文献
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陆架波的性质如频散关系、形成机制等受地形影响。研究地形对陆架波的性质影响具有重要意义。基于陆架拦截波理论,数值计算了分段线性地形下不同宽度陆架上陆架拦截波的频散关系、长波假设下波动的相速度、阻尼情况下的波动耗散率以及强迫波的外力影响因子。分析了陆架宽度及坡度对自由及强迫陆架拦截波性质的影响。陆架宽度影响陆架拦截波的频散关系。陆架变宽,使得长波频散曲线的斜率增大。陆架宽度的增加使第一模态陆架拦截波有明显的性质变化:相速度增大,波动受辐散影响的程度变大,摩擦衰减距离增大,且风应力旋度在波动的生成机制中起到的作用渐强。在宽的陆架上,研究陆架拦截波的生成及强迫波的振幅时,应充分考虑风应力旋度的作用。第二、三模态波动的相速度受陆架坡度的影响较大,但摩擦衰减距离基本都在200km左右,几乎不随陆架宽度改变,属于局地波。 相似文献
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Marine airborne multispectrum scanner (MAMS) onboard the China marine surveillance plane can be used to survey marine environment, resources and disaster and provide the technical support for high-frequency, high-efficiency and high-resolution remote sensing monitoring for the coastal management. MAMS did not have the IMU/POS equipment, so it brought severe challenge for the geometry correction. One airborne geometry correction method is introduced for marine multispectrum data without the attitude information. First, it is the coarse geometry correction, which simulates the roll angle and pitch angle of plane according to the ideal flying model; the second step is the precise geometry correction by using the SPOT orthogonal projected data as the reference of registration, based on maximization of alignment metric method. With the validation, relative error of coarse correction is 81.42 m compared with SPOT data, and 11.3 m for precise correction. This method provides the high precision localization information for the oceanic remote sensing and application, and establishes the foundation for monitoring the marine resource and environment. 相似文献
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A computer simulation is used to analyze errors in high-frequency (HF) radar ocean surface current measurements. Two pointing algorithms used for current extraction, a direction finding approach using MUltiple SIgnal Characterization (MUSIC) developed by Schmidt (1986), and conventional beam forming, are compared in terms of the effect of variations in sea state parameters on current measurement error. The radar system parameters used in the simulation were taken from the University of Michigan's multi-frequency coastal radar (MCR), which operates on four frequencies from 4.8 to 21.8 MHz and employs an eight-element linear phased array for its receive antenna. Results show MUSIC direction finding to be applicable to phased array systems and to have a better sensitivity to sharp current features, but larger random error than traditional beam forming methods. Also, for cases where beam forming errors are dominated by beam width or low signal to noise ratio, results show MUSIC to be a viable alternative to beam forming 相似文献
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This paper extends the theory on capture width, a commonly used performance indicator for a wave energy converter (WEC). The capture width of a linear WEC is shown to depend on two properties: the spectral power fraction (a property introduced in this paper), which depends entirely on the sea state, and the monochromatic capture width, which is determined by the geometry of the WEC and the chosen power take off (PTO) coefficients. Each of these properties is examined in detail. Capture width is shown to be a measure of how well these two properties coincide. A study of the effects of PTO control on the capture width suggests that geometry control, a form of control that has not been the focus of much academic research, despite its use in the wave energy industry, deserves more attention. The distinction between geometry control and PTO control is outlined. While capture width is a valuable design tool, its limitations must be recognised. The assumptions made in the formulation of capture width are listed, and its limitations as a tool for estimating annual power capture of a WEC are discussed. 相似文献