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针对半参数回归模型求解过程可能出现的法方程病态问题，提出了用岭估计原则改进半参数模型的求解。通过模拟算例将岭估计解法和其他方法进行了比较，结果表明，岭估计解法能较好地解决半参数回归模型求解过程中的病态问题。 相似文献
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对KSS31M型海洋重力仪阻尼延迟时间进行了修正,分别用修正前的110s阻尼延迟时间和修正后的60s阻尼延迟时间对南海某工区的重力数据进行了校正和处理,结果表明:用110s阻尼延迟时间对数据进行校正后得到的测量精度在平差前为1.6mGal,平差后为1.0mGal,用60s阻尼延迟时间对数据进行校正后得到的测量精度在平差前为1.4mGal,平差后为0.8mGal,平差前和平差后的测量精度均提高了0.2mGal。此结果证明了利用船只机动转向确定海洋重力仪在测量过程中的实际阻尼延迟时间方法的必要性和实际应用价值。 相似文献
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基于国际共享MW9006航次船载实测资料,针对目前已经被广泛运用的最小二乘和半系统差调整两种平差模型进行讨论,提出了一种适用于不规则复杂测网下重力测线数据的平差方法。规则测线网下,随着半系统差调整平差次数的增加,其结果趋近于最小二乘平差。然而,在实际应用于不规则测线网平差中时,由于存在斜交主测线和联络线的补充测线,最小二乘平差只能损失部分交点数据不参与平差而降低精度,而半系统差调整可通过遍历测线的方式计算全部交点并参与平差,但存在交点差重复参与计算的问题。所以两种平差方法又均有局限,亟待提出一种新的方法来处理解决上述问题。基于补充测线与主测线、联络线交点的分布及大小等因素,将不规则测线网分为6种类型开展最小二乘平差和半系统差调整平差工作。在对6种结果进行评价时,选取了测线精度、交点差均方根及平差结果整体均一性等三个要素进行分析评估,并最终确定不规则测线网下的平差方式及结果,最终航次内114个交点均方根降为(±1.84×10-5)m/s2。 相似文献
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北部湾南部重力柱状样的MSCL地声学性质测量及分析 总被引：1，自引：0，他引：1
利用钻孔多参数连续记录仪(multi-sensorcorelogger,MSCL),对在南海北部湾南部海区所取得的6个孔重力柱状样进行了测量,获得了连续P波波速、湿密度和孔隙度数据。在室内实验室对柱状样分样之后的沉积物样品进行了孔隙度与湿密度的测定。利用不同的统计回归方法对所获得的6个柱状样的孔隙度与P波波速进行相关分析,并对比室内测量的P波波速、湿密度、孔隙度,建立了基于孔隙度数据对沉积物P波波速进行预测的方法,对MSCL测量方法的优缺点进行了讨论。结果表明,MSCL测量结果与实验室柱状样测定结果较为吻合。样品所在深度对声速的变化影响不大。孔隙度与声速的多项式回归,样条插值回归和GAM模型回归都获得了较高的相关系数,GAM模型可以提供一个较为接近测量值的声速预测方法。MSCL用来测量海底沉积物,可以获得大量的高密度、高精度的沉积物地声学及其他参数数据,但是,如果空气混入沉积物样品中则会导致MSCL测量结果失真。该研究为使用MSCL在区域海底地声学性质、恢复区域海洋沉积历史、海底地声学模型建立等研究提供了参考。 相似文献
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A two-dimensional non-hydrostatic ocean model and a hydrostatic version of the same model are used to simulate convective adjustment, without the use of an instantaneous adjustment parameterization. The model geometry is a domain on the vertical plane of width 40 km and depth 500 m. Model results for four cases are examined: hydrostatic and non-hydrostatic, at 0.1 and 1 km spatial resolution. The convectively adjusted stable state obtained in all four cases are qualitatively similar; thus the hydrostatic approximation does not eliminate convective adjustment. The details of the simulated convective plumes depend on resolution and whether the hydrostatic approximation is made. The adjusted state has significant stratification which cannot be captured by the conventional instantaneous adjustment or diffusion-based parameterizations. We also compare the results to the case when an instantaneous adjustment parameterization is used. 相似文献
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JUN Ki Cheon JEONG Weon Mu CHOI Jin Yong PARK Kwang Soon JUNG Kyung Tae KIM Mee Kyung CHAE Jang Won QIAO Fangli 《海洋学报(英文版)》2015,34(12):19-28
Record-breaking high waves occurred during the passage of the typhoon Bolaven (1215) (TYB) in the East China Sea (ECS) and Yellow Sea (YS) although its intensity did not reach the level of a super typhoon. Winds and directional wave measurements were made using a range of in-situ instruments mounted on an ocean tower and buoys. In order to understand how such high waves with long duration occurred, analyses have been made through measurement and numerical simulations. TYB winds were generated using the TC96 typhoon wind model with the best track data calibrated with the measurements. And then the wind fields were blended with the reanalyzed synoptic-scale wind fields for a wave model. Wave fields were simulated using WAM4.5 with adjustment of Cd for gust of winds and bottom friction for the study area. Thus the accuracy of simulations is considerably enhanced, and the computed results are also in better agreement with measured data than before. It is found that the extremely high waves evolved as a result of the superposition of distant large swells and high wind seas generated by strong winds from the front/right quadrant of the typhoon track. As the typhoon moved at a speed a little slower than the dominant wave group velocity in a consistent direction for two days, the wave growth was significantly enhanced by strong wind input in an extended fetch and non-linear interaction. 相似文献
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Linear structural relations express the linear relationship between random variables when each of the variables under consideration is subjected to inherent variability and measurement error. The linear structural method is more general than the classical regression, which is often used incorrectly in calibration of altimeter data or validation of wave model results. In this work the linear structural method is elaborated and applied for the adjustment of TOPEX/Poseidon (T/P) data by means of in situ measured wave data in the Aegean Sea. In addition, a comparison of the buoy and T/P data with the WAM wave model predictions is performed revealing an underestimation trend of the model. 相似文献
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Advance planning is essential for the production of quality data. Before any planning is attempted, a well-defined model of the problem under investigation must be established. The measurements may be made to test the model or they may be used with the model to clarify or solve the problem under investigation.In the planning process, chemical measurement must be considered as a system consisting of sampling, calibration, analysis, and data processing. Appropriate quality assurance procedures must be applied to ensure statistical control and evaluation of the data. Because of the interdependence of the various aspects of measurement, they must be planned in a coordinated mode, involving subject matter, measurement, and statistical expertise.Details of all of the above are discussed in the paper. 相似文献
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A conditional beta probability density function is employed to model time-delay measurement errors associated with sensors used in triangulation ranging applications. This type of density function is less restrictive than the beta density used in previous analyses in that end points can be extended out beyond the imposed range constraints and data editing is allowed before range calculations. The resulting conditional range density function is computed along with the mean and variance. Comparisons are made of the pertinent range statistics associated with the beta and conditional beta density functions. Finally, the conditional beta density function range statistics are compared with those obtained from a gated Gaussian density function for equivalent values of time-delay measurement error standard deviation. The Gaussian statistics are determined via Monte-Carlo simulation. 相似文献
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In this paper, the characteristic difference schemes are adopted and the proof calculation of actual measurement data of the Qiantangjiang River is made. The calculating result is in agreement with actual measurement data and conforms with the requirements of the engineering (see Table 1, Table 2 and Fig. 2).In the end, the hydraulics model Eq. (16) is discussed and the discussion shows that the characteristic difference schemes (21) can be used to calculate the tidal bore (discontinuity solutions) because the schemes have a pesudo-viscous term (see Theorem I.) 相似文献
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V. O. Kakhiani K. I. Patarashvili S. D. Tsakadze M. V. Kalashnik L. Kh. Ingel 《Izvestiya Atmospheric and Oceanic Physics》2009,45(4):403-410
The results of laboratory modeling of geostrophic adjustment in a shallow-water layer in rotating paraboloid are presented.
According to the Rossby-Obukhov theory, this process excites nonstationary wave and stationary vortex (geostrophic) components
of motion in a rotating fluid. In our experiments, the wave and vortex components were excited by extracting a preliminarily
imbedded hemisphere (which made the initial distribution of the depth of the fluid inhomogeneous) from the central area of
a rotating vessel with a parabolic base. Under this excitation technique, a prominent cyclonic eddy is formed in the central
portion; the structure of this eddy is satisfactorily described within the linear theory of adjustment. Along with the shallow-water
experiments, the published experimental data on modeling geostrophic adjustment in a two-layer medium are analyzed. A simple
analytic solution to the corresponding problem of the adjustment theory is obtained, and this solution agrees with the experiment. 相似文献
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Based on an analysis of the source of errors in marine gravity measurements, an error model, firstly, is constructed mathematically which can characterize the change of systematic errors and with which a new crossover adjustment model is presented in this paper. Then, two methods of compensating the systematic errors are proposed, i.e., the self-calibrating adjustment and the a-posteriori compensation. Some questions involved in solving the adjustment problem, such as the rank deficiency, the choice of error model, the weighting of model parameters and the significance test of compensation efficiency, etc., are discussed in detail. Finally, a practical survey network is used as a case study to test the efficiency and reliability of the two compensation methods. 相似文献
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Based on an analysis of the source of errors in marine gravity measurements, an error model, firstly, is constructed mathematically which can characterize the change of systematic errors and with which a new crossover adjustment model is presented in this paper. Then, two methods of compensating the systematic errors are proposed, i.e., the self-calibrating adjustment and the a-posteriori compensation. Some questions involved in solving the adjustment problem, such as the rank deficiency, the choice of error model, the weighting of model parameters and the significance test of compensation efficiency, etc., are discussed in detail. Finally, a practical survey network is used as a case study to test the efficiency and reliability of the two compensation methods. 相似文献
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《Ocean Modelling》2000,2(1-2):61-72
Numerical models of basin-to-global scale ocean circulation generally take thousands of model years to converge to a final steady-state. The long timescale is set by the slow adjustment of the ocean's overall stratification to the classical vertical advective–diffusive balance. During much of this adjustment period, the time evolution of many model variables appears to be an approximately exponential decay to the final state. The adjustment of the model can be accelerated by extrapolating zonal-average temperature and salinity fields forward in time based on this exponential decay. Tests with the GFDL MOM-2, a primitive-equation numerical model, show that the extrapolation does not yield an exact solution, but can shorten integration times by a factor of two to three. 相似文献