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61.
评价储层含油性的热解参数校正方法及其应用 总被引:2,自引:0,他引:2
评价储层含油性时,热解参数S1+S2是一项有效参数。其中S2相对稳定,S1则随样品类别或露置时间的不同而发生变化。岩心样品的随钻解分析值比较接近真实,岩屑和井壁取心样品的S1会明显损失。而目前多数探井心进尺少,大多为岩屑录井。 相似文献
62.
二维地电条件下充电法地形改正的一种方法 总被引:2,自引:0,他引:2
本文首先讨论了充电法地形改正方法及存在的问题,提出了一种基于比值法思想的地改方法,经理论模型验算表明,有较好的地改效果 相似文献
63.
64.
GPS水汽遥感中的大气干延迟局地订正模型研究 总被引:9,自引:2,他引:9
在GPS遥感水汽过程中,大气干延迟模型的精度直接影响水汽遥感的精度。根据广东清远站1995~2001年的气象探空资料,计算了GPS水汽测量中的实际大气干延迟。在此资料基础上,利用地面气象要素建立了大气干延迟的年和分月局地订正模型。分析结果表明,年模型的精度优于目前广泛使用的普适模型;月模型与年模型相比,效果不是很明显,建立局地分月订正模型意义不大;在对高度角的敏感程度上,局地模型略大些;当高度角小于75时,大气干延迟弯曲路径与直线路径之差ΔS随天顶角增大而迅速增大。 相似文献
65.
应用6S辐射传输模式对MODIS可见光到中红外波段的反射率进行大气订正,订正过程分两步进行:首先设定地表为朗伯体,再应用二向反射模型BRDF进行订正,订正结果与美国MODIS研究组应用MAS实验结果进行比较表明,两者变化趋势是一致的;经过臭氧、水汽、气溶胶等散射吸收订正,对于一定范围的反射率,大气订正使植被区红光波段反射率ρ1降低、近红外波段反射率ρ2增加,蓝光波段反射率ρ3降低;大气订正后,归一化植被指数INDV较大气订正前有所增加,增加的最大值为0.104,抗土壤-大气植被指数IEV值略有减小,减小的最大值为0.005。 相似文献
66.
67.
Analysis of Sediments and Soils by X-Ray Fluorescence Spectrometry Using Matrix Corrections Based on Fundamental Parameters 总被引:2,自引:0,他引:2
Jacinta Enzweiler Maria Aparecida Vendemiatto 《Geostandards and Geoanalytical Research》2004,28(1):103-112
Wavelength dispersive X-ray fluorescence spectrometry (WD-XRF) is widely used for the analysis of soils and sediments using well characterised procedures. However, difficulties can occur with samples such as unknowns containing small amounts of ore materials and samples collected from contaminated sites where trace elemental concentrations can exceed the concentration range for routine analysis. We studied the performance of a commercially available method, based on fundamental parameters (FP) to correct matrix effects. The spectrometer was originally calibrated with elemental or simple compound calibrants. Samples were analysed as pressed powder pellets. Eighteen sediment and soil reference materials, three of them with certified values for some of their constituents, were used to evaluate accuracy, by comparing results with recommended values and their standard deviations (RV ± 2s) or certified values and their confidence intervals (CV ± Cl). When results fell systematically outside these intervals, calibrations were refined with geochemical reference materials. The best agreement of results with recommended and certified values was obtained when the contents of H2 O and C in each sample were included as matrix constituents during calculations. The detection limits of trace elements tended to be relatively high, because the measuring conditions employed were not maximised for sensitivity. The main advantage of the method tested was that it enabled the analysis of samples with high concentrations of trace elements and the determination of elements such as F, Bi, Sb and W, which are not commonly included in quantitative XRF analysis of geological samples. 相似文献
68.
Bernard Pelletier Pierre Dutilleul Guillaume Larocque James W. Fyles 《Mathematical Geology》2004,36(3):323-343
In geostatistical studies, the fitting of the linear model of coregionalization (LMC) to direct and cross experimental semivariograms is usually performed with a weighted least-squares (WLS) procedure based on the number of pairs of observations at each lag. So far, no study has investigated the efficiency of other least-squares procedures, such as ordinary least squares (OLS), generalized least squares (GLS), and WLS with other weighing functions, in the context of the LMC. In this article, we compare the statistical properties of the sill estimators obtained with eight least-squares procedures for fitting the LMC: OLS, four WLS, and three GLS. The WLS procedures are based on approximations of the variance of semivariogram estimates at each distance lag. The GLS procedures use a variance–covariance matrix of semivariogram estimates that is (i) estimated using the fourth-order moments with sill estimates (GLS1), (ii) calculated using the fourth-order moments with the theoretical sills (GLS2), and (iii) based on an approximation using the correlation between semivariogram estimates in the case of spatial independence of the observations (GLS3). The current algorithm for fitting the LMC by WLS while ensuring the positive semidefiniteness of sill matrix estimates is modified to include any least-squares procedure. A Monte Carlo study is performed for 16 scenarios corresponding to different combinations of the number of variables, number of spatial structures, values of ranges, and scale dependence of the correlations among variables. Simulation results show that the mean square error is accounted for mostly by the variance of the sill estimators instead of their squared bias. Overall, the estimated GLS1 and theoretical GLS2 are the most efficient, followed by the WLS procedure that is based on the number of pairs of observations and the average distance at each lag. On that basis, GLS1 can be recommended for future studies using the LMC. 相似文献
69.
Nicolas Domange Caroline Grégoire Véronique Gouy Michèle Tremolières 《Comptes Rendus Geoscience》2004,336(1):49-58
The soil solution sampling by ceramic cups allows pesticide transfer monitoring in the soil during long times. The ageing of material involves a bias in the sampling results. In laboratory, the comparison of two types of ceramic suction cups, new and installed in situ during four years, shows a modification of the hydrodynamic properties and a possible evolution of the adsorption capacity of the matrix. The passage rate, as well qualitative as quantitative, is better for the old material. Recommendations about site management are finally exposed. To cite this article: N. Domange et al., C. R. Geoscience 336 (2004). 相似文献
70.
基于EM算法和单幅雷达图像阴影的控制点坡度校正 总被引:1,自引:0,他引:1
对在我国现有的条件下进行控制点坡度校正的必要性进行了阐述,并分析了EM算法。根据EM算法以及基于区域增长的余弦散射模型建立了控制点坡度校正模型,并用河北省张北地区的雷达影像进行了实验,取得了较高的精度初值。 相似文献