地震剖面随机分形插值方法   总被引：10，自引：3，他引：7  

杨绍国  何明星 《物探化探计算技术》1998,20(3):218-221

本文讨论了随机分形插值方法及其在地震资料处理中的应用。实验结果表明,随机分形插值方法是提高地震分辨率的简单有效方法。  相似文献   

Interpolation with Splines in Tension: A Green''s Function Approach   总被引：2，自引：0，他引：2  

Paul Wessel  David Bercovici 《Mathematical Geology》1998,30(1):77-93

Interpolation and gridding of data are procedures in the physical sciences and are accomplished typically using an averaging or finite difference scheme on an equidistant grid. Cubic splines are popular because of their smooth appearances; however, these functions can have undesirable oscillations between data points. Adding tension to the spline overcomes this deficiency. Here, we derive a technique for interpolation and gridding in one, two, and three dimensions using Green's functions for splines in tension and examine some of the properties of these functions. For moderate amounts of data, the Green's function technique is superior to conventional finite-difference methods because (1) both data values and directional gradients can be used to constrain the model surface, (2) noise can be suppressed easily by seeking a least-squares fit rather than exact interpolation, and (3) the model can be evaluated at arbitrary locations rather than only on a rectangular grid. We also show that the inclusion of tension greatly improves the stability of the method relative to gridding without tension. Moreover, the one-dimensional situation can be extended easily to handle parametric curve fitting in the plane and in space. Finally, we demonstrate the new method on both synthetic and real data and discuss the merits and drawbacks of the Green's function technique.  相似文献   

Surface representations reproducing given digitized contour lines   总被引：1，自引：0，他引：1  

S. Auerbach  H. Schaeben 《Mathematical Geology》1990,22(6):723-742

In the practice of administrative or engineering geosciences, the problem of deriving a digital surface representation from a map displaying contour lines of the interesting quantity is quite often encountered. First, alpha-numerical data are retrieved from the map by digitizing these contour lines pointwise into polygons. However, common gridding algorithms are known to fail at adequately reproducing the input contour lines due to the inhomogeneous and anisotropic areal distribution of the sites of the data sampled from given contour lines. Therefore, we suggest a new algorithm; the basic elements of its first stage are a constrained Delaunay triangulation of the data sites honoring their natural neighborhood relationship—i.e., whether they belong to the same contour line or not, and linear interpolation according to this triangulation of the data domain. In a second stage, a Bezier-Bernstein or simplex B-spline representation is easily achieved if a C₁ or C₂ smooth representation is required. At this stage, also, discontinuities of the function or its first directional derivatives with known locations in the data domain may be represented, provided this additional information has been taken into account when the triangulation was performed. The algorithm is numerically stable and efficient, and allows external interaction by the user to introduce his/her additional knowledge of the phenomenon to be studied, which may not be explicitly inherent in the available data.  相似文献   

对流扩散方程欧拉──拉格朗日方法的B─样条插值格式     

杨宗严 《中国海洋大学学报(自然科学版)》1994,(2)

利用Ｂ－样条函数．文中发展了一个对流扩散方程欧拉－拉格朗日方法的插值格式．改善了其数值频散性。算例表明，此格式优于一次和二次插值格式。文中给出了Ｂ－样条插值格式的二维及三维推广。  相似文献   

基于样条函数对线状目标矢量化的表示     

邹芳  彭轶 《海洋测绘》2007,27(3):12-15

在分析遥感影像中提取的线状目标的基础上,利用样条插值函数,对提取的线状目标矢量化表示进行了研究。主要过程包括目标的分解、插值点的选取、插值函数的选择、特征点的增加等。实验结果表明,提出的方法能有效地表示提取的线状目标,减少数据冗余,具有好的光滑性。  相似文献   

Altimeter's Capability of Reconstructing Realistic Eddy Fields Using Space-Time Optimum Interpolation     

Tsurane Kuragano  Masafumi Kamachi 《Journal of Oceanography》2003,59(6):765-781

Sea surface height anomaly maps of realistic eddy activity were obtained by applying space-time optimum interpolation to altimeter data. Analysis error and rate of reconstructing eddy signals were investigated by taking account of: 1) dependency on orbit configurations of single and multiple altimeters; 2) dependency on space-time scales of realistic, dominant eddies; and 3) effect of space-time scales of eddy propagation. Large-scale sea surface height anomalies are subtracted from altimeter data by applying an along-track filter to allow easy handling of eddy signals. The space-time scales of the first-guess error in the optimum interpolation are statistically evaluated by fitting a space-time anisotropic Gaussian function to space-time-distributed correlation coefficients of sea surface height using the TOPEX data. The results of the optimum interpolation clarify the followings: 1) ERS has a better capability of reconstructing eddy signals than TOPEX. Comparison of maps from multi-altimeter data shows that TOPEX+ERS has a better capability than Jason−1+TOPEX in lower latitudes and vice versa in higher latitudes, though the differences are small. 2) The small space-time scale yields a low reconstruction rate in marginal seas and alongside the equator. The persistent timescale is large, and westward propagation is dominant in the subtropical and subarctic regions, where the reconstruction rates are high. 3) The optimum interpolation, taking account of eddy propagation, provides higher reconstruction rates than that taking no account of the propagation. The effect of propagation on the optimum interpolation is greater when it is applied to single-altimeter data than to multi-altimeter data. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

厦门海域浅水三维潮流场动力学模型   总被引：2，自引：0，他引：2       下载免费PDF全文

温生辉  蔡启富  汤军健  蔡嵩 《海洋学报》2003,25(2):1-17

基于Casulli的三维浅水模型,改进浅滩处理方法,并入简化的紊流闭合模型,形成完整的海洋动力学基本方程组,改进了紊流闭合模型的求解方法,动力学模拟结果与实测结果符合良好,海域中大量浅滩的干出与淹没的面积和位置与实际情况吻合良好.本模型是厦门海域海洋动力学理论研究中第一个完全的三维斜压潮流场模型,全部程序用FORTRAN语言独立开发和编写.  相似文献   

Assimilation of Sea Surface Temperature in a Global Hybrid Coordinate Ocean Model     

Yueliang CHEN  Changxiang YAN  Jiang ZHU 《大气科学进展》2018,35(10):1291-1304

The Hybrid Coordinate Ocean Model(HYCOM) uses different vertical coordinate choices in different regions. In HYCOM, the prognostic variables include not only the seawater temperature, salinity and current fields, but also the layer thickness. All prognostic variables are usually adjusted in the assimilation when multivariate data assimilation methods are used to assimilate sea surface temperature(SST). This paper investigates the effects of SST assimilation in a global HYCOM model using the Ensemble Optimal Interpolation multivariate assimilation method. Three assimilation experiments are conducted from 2006–08. In the first experiment, all model variables are adjusted during the assimilation process. In the other two experiments, the temperature alone is adjusted in the entire water column and in the mixed layer. For comparison, a control experiment without assimilation is also conducted. The three assimilation experiments yield notable SST improvements over the results of the control experiment. Additionally, the experiments in which all variables are adjusted and the temperature alone in all model layers is adjusted, produce significant negative effects on the subsurface temperature. Also, they yield negative effects on the subsurface salinity because it is associated with temperature and layer thickness. The experiment adjusting the temperature alone in the mixed layer yields positive effects and outperforms the other experiments. The heat content in the upper 300 m and 300–700 m layers further suggests that it yields the best performance among the experiments.  相似文献   

高寒草甸区典型景观单元土壤养分空间变异性研究   总被引：9，自引：2，他引：7  

龙训建  钱鞠  张春敏  王根绪  李元寿 《冰川冻土》2008,30(1):139-146

应用GIS技术和地统计学空间内插法,对黄河源区达日县跨热洼尔玛流域高寒草甸小流域典型景观单元土壤有机质、全氮和全磷的空间分布特征进行了研究.结果表明: 高寒草甸土壤养分(全氮、有机质、全磷)最佳拟合模型为球状模型;在小流域尺度范围内,土壤养分空间变异性依次为: 全氮＞有机质＞全磷;其中高寒草甸土壤全氮含量具有强空间变异,块金系数(C0/(C0 C))为23.5%,有机质和全磷属于中等空间变异,其块金系数(C0/(C0 C))分别为35.9%、41.7%;全氮、有机质和全磷的有效变程分别为2 133 m、1 412 m和1 239 m.区域土壤养分影响因素分析显示: 不同植被覆盖下土壤有机质和养分的积累和平衡状况存在差异,其空间变异主要受海拔、地形、坡度、植被、根系分布状况等因素影响.  相似文献   

GPS/GLONASS集成的CORS网大气延迟插值模型比较分析     

孙伟  张绍成  耿胜辉 《测绘工程》2016,25(7):1-6

结合实际数据,对GPS/GLONASS集成的CORS网中利用参考站间的大气延迟内插流动站处的误差改正量的各种内插算法进行比较。比较结果认为:双差电离层延迟改正采用克里金插值模型(KRG)方法精度最高,精度优于3cm;而对流层延迟误差改正中,GPS采用最小二乘配置模型(LSC)插值方法效果最好,精度一般可达3cm,而GLONASS则应采用3阶趋势面模型(LSM3)进行内插,精度为4cm。  相似文献