Modeling the Dynamic Gravity Variations of Northeastern Margin of Qinghai-Xizang （Tibet） Plateau by Using Bicubic Spline Interpolation Function     

Zhu Yiqing 《中国地震研究》2005,19(4):346-353

INTRODUCTIONThe study of earthquakeforecast based on gravity measurement has been carried out for almost30yearsin China,and remarkable progress has been made(Jia Minyu,et al.,2000;Zhu Yiqing,etal.,2001).However,constrained byobservationtechniques and moni…  相似文献   

Observation and analysis of geomagnetic abnormity associated with the M_S=5.7 Jiu-jiang-Ruichang earthquakeb     

顾左文  张毅  姚同起  高金田  刘欣  陈斌  詹志佳  顾春蕾 《地震学报(英文版)》2006,(6)

Introduction On November26,2005,the MS=5.7Jiujiang-Ruichang earthquake occurred with the epicen-ter of29°43′N and115°43′E.However,this area is not a major monitoring range with a few earth-quakes and therefore,it lacks conventional precursory seismic data.In the project of“2005.0China geomagnetic chart”,some three-component geomagnetic surveys,with the average distance of70km between adjacent stations,were carried out in2004in this area.And fortunately the data from these surveys can…  相似文献   

关于计算机自动绘制光滑曲线的数学方法的探索   总被引：1，自引：0，他引：1  

和正民 《城市地质》1998,10(1):17-24

在计算机绘制地图光滑曲线的方法中,线形插值法计算简单,失真率较大。正轴抛物线平均加权法在一些特殊情况下曲线会偏离节点。斜轴抛物线平均加权法可以获得比较满意的结果,但计算复杂,不利于在微机上运用。本文介绍的张力样条函数插值法,方法严密,计算亦不复杂,对小型的制图系统比较适用。其显著特点是具有一个张力系数σ,当σ→０时,张力样条函数就等同于三次样条函数;当σ→∞时,则退化为分段线形函数。因此,可以选择合适的σ,使得节点间的曲线为最短,既能消除可能出现的多余拐点,又能保持曲线的光滑性。  相似文献   

Regression model for generating time series of daily precipitation amounts for climate change impact studies     

T. A. Buishand  A. M. G. Klein Tank 《Stochastic Environmental Research and Risk Assessment (SERRA)》1996,10(2):87-106

The precipitation amounts on wet days at De Bilt (the Netherlands) are linked to temperature and surface air pressure through advanced regression techniques. Temperature is chosen as a covariate to use the model for generating synthetic time series of daily precipitation in a CO₂ induced warmer climate. The precipitation-temperature dependence can partly be ascribed to the phenomenon that warmer air can contain more moisture. Spline functions are introduced to reproduce the non-monotonous change of the mean daily precipitation amount with temperature. Because the model is non-linear and the variance of the errors depends on the expected response, an iteratively reweighted least-squares technique is needed to estimate the regression coefficients. A representative rainfall sequence for the situation of a systematic temperature rise is obtained by multiplying the precipitation amounts in the observed record with a temperature dependent factor based on a fitted regression model. For a temperature change of 3°C (reasonable guess for a doubled CO₂ climate according to the present-day general circulation models) this results in an increase in the annual average amount of 9% (20% in winter and 4% in summer). An extended model with both temperature and surface air pressure is presented which makes it possible to study the additional effects of a potential systematic change in surface air pressure on precipitation.  相似文献   

徐淮地区冬小麦叶龄与有效积温的样条模式     

武金岗  高苹  汤志成  陶炳炎 《气象》1996,22(10):51-53

分析冬小麦越冬前叶龄变化，温度有效性随播期，发育期变化及其对叶龄的影响。用样条回归方法，建立了叶龄与有效积温模式，并用该模式确定冬小麦适播期以及插补缺测的叶龄。  相似文献   

Polynomial smoothing of quiet-time magnetic variations for an irregularly spaced array of sites     

Michael L. Rossen  John F. Hermance 《Pure and Applied Geophysics》1987,125(1):41-65

Both magnetospheric and solid Earth geophysicists often employ two-dimensional arrays of recording variometers to reconstruct the spatial distribution of transient magnetic field variations at the Earth's surface. These discrete data are typically interpolated over a dense grid and the results, for example, are contoured. Few studies, however, have explored the efficacy of employing various polynomial forms for interpolating the same data set, nor have they examined how regional polynomial forms relate to magnetic variation sources on a global scale. The present study addresses some of these concerns. We quantify the characteristics of various smoothed models (i.e., low-order polynomial trend surfaces) for the same data set from a subglobal network of magnetic variometers. Using a relatively quiet interval of undisturbed diurnal variation, we characterize the spatial distribution of the three individual magnetic vector components at a single instant of time—or for what we call a ‘time slice’. We then explore how our model functions are affected by the presence or absence of various site data, i.e., what is the ‘information content’ of a particular site in our array and how important is it to constraining the final smooth model function that we derive? Finally, we explore how such local model functions are affected by including data from outside the array by studying the relation between our local polynomial forms and the global source fields from which they derive.  相似文献   

Smoothing and interpolation by kriging and with splines   总被引：1，自引：0，他引：1  

G. S. Watson 《Mathematical Geology》1984,16(6):601-615

Let scalar measurements at distinct points x₁, , x_n be y₁, , y_n.We may look for a smooth function f(x)that goes through or near the points (x_i, y_i).Kriging assumes f(x)is a random function with known (possibly estimable) covariance function (in the simplest case). Splines assume a definition of the smoothness of a nonrandom function f(x).An elementary explanation is given of the fact that spline approximations are special cases of the solution of a kriging problem.  相似文献   

GPS载波相位平滑伪距精度分析与应用探讨   总被引：5，自引：2，他引：5  

唐卫明  刘智敏 《测绘信息与工程》2005,30(3):37-39

分析了载波相位平滑伪距在动态短基线解算、精密单点定位、动态长基线解算的精度,提出了载波相位平滑伪距在多种高精度定位中的应用。  相似文献   

应用样条函数处理GPS共视数据     

李滚 《测绘信息与工程》2005,30(4):17-19

为克服Vondrak方法平滑GPS共视比对数据的两端效应和缺值点处的插值问题,应用样条函数平滑和插值方法对NTSC和CRL的GPS共视数据进行了分析研究。结果表明:这种方法可解决Vondrak平滑方法的两端效应现象;与CircularT的数据比较,用样条函数平滑数据之后,再进行三次样条插值,缺值点的内符合精度有所提高,整体内符合精度也有所提高。  相似文献   

Identification of parametric ground motion random fields from spatially recorded seismic data     

A. Zerva  J. L. Beck 《地震工程与结构动力学》2003,32(5):771-791

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