利用分形参数进行地貌定量分区研究——以鄂尔多斯块体及周边为例          下载免费PDF全文

毕丽思  何宏林  魏占玉  石峰 《第四纪研究》2011,31(1):137-149

地貌分区是地学研究的基础内容之一.传统的地貌分区大多是定性的划分,随着数字地形技术以及分形分析方法的成熟,利用分形参数进行定量化的地貌分区成为可能.本文利用水平分辨率为90m的SRTM数据,采用元分维模型,通过变差函数法计算了鄂尔多斯块体及周边地形的分形参数.在65×65,129×129以及257×257等3种尺度滑动...  相似文献   

序贯模拟方法在储层建模中的应用研究   总被引：3，自引：0，他引：3  

胡先莉  薛东剑 《成都理工学院学报》2007,34(6):609-613

条件模拟方法是地质统计学发展的一个主要方向和研究热点。作者通过序贯模拟方法在储层建模中的应用，对模拟结果进行了参数统计和变异函数分析；并对克立格和序贯模拟方法进行了比较。应用研究的结果证明了该方法的各种特点，弥补了条件模拟方法在理论研究上的不足，为进一步的方法改进和拓宽其应用范围提供了理论依据和实例参考。  相似文献   

AN ANALYSIS OF THE ATMOSPHERIC WATER BALANCE OVER THE SOUTHERN HEMISPHERE     

David A. Howarth  John N. Rayner 《自然地理学》2013,34(6):513-535

An analysis of the atmospheric water balance over the Southern Hemisphere is conducted for the time period June 1980 through May 1984 that includes the 1982–1983 El Niño event. Notable spatial and temporal variations are evident in the moisture flux divergence fields, in the mean meridional transport of water vapor, and in the moisture content of portions of the tropical atmosphere that are attributable to the 1982–1983 ENSO event. Estimates of the net gain/loss of atmospheric water are provided for 10° latitude belts; although the magnitudes of the differences between evaporation and precipitation fall within the range of previous estimates, they are most probably underestimated. [Key words: atmospheric water balance, El Niño, hydrologic cycle, southern hemisphere, water vapor flux.]  相似文献   

Estimating the spatial pattern of human-caused forest fires using a generalized linear mixed model with spatial autocorrelation in South Korea     

Hanbin Kwak  Joachim Saborowski  Si-Young Lee  Myoung-Soo Won  Kyo-Sang Koo 《International journal of geographical information science》2013,27(9):1589-1602

Most forest fires in Korea are spatially concentrated in certain areas and are highly related to human activities. These site-specific characteristics of forest fires are analyzed by spatial regression analysis using the R-module generalized linear mixed model (GLMM), which can consider spatial autocorrelation. We examined the quantitative effect of topology, human accessibility, and forest cover without and with spatial autocorrelation. Under the assumption that slope, elevation, aspect, population density, distance from road, and forest cover are related to forest fire occurrence, the explanatory variables of each of these factors were prepared using a Geographic Information System-based process. First, we tried to test the influence of fixed effects on the occurrence of forest fires using a generalized linear model (GLM) with Poisson distribution. In addition, the overdispersion of the response data was also detected, and variogram analysis was performed using the standardized residuals of GLM. Second, GLMM was applied to consider the obvious residual autocorrelation structure. The fitted models were validated and compared using the multiple correlation and root mean square error (RMSE). Results showed that slope, elevation, aspect index, population density, and distance from road were significant factors capable of explaining the forest fire occurrence. Positive spatial autocorrelation was estimated up to a distance of 32 km. The kriging predictions based on GLMM were smoother than those of the GLM. Finally, a forest fire occurrence map was prepared using the results from both models. The fire risk decreases with increasing distance to areas with high population densities, and increasing elevation showed a suppressing effect on fire occurrence. Both variables are in accordance with the significance tests.  相似文献   

随机反演在陆丰13-1油田储层预测中的应用   总被引：1，自引：0，他引：1  

刘丹  徐伟 《物探化探计算技术》2012,34(3):331-335,240,241

这里以陆丰13-1油田为例,研究发现井上波阻抗曲线并不能有效区分砂岩储层和泥岩非储层,故对孔隙度数据体进行了反演.首先对井上孔隙度曲线进行直方图统计分析,变差函数分析及孔隙度和波阻抗的相关性分析,然后用高斯模拟加模拟退火的随机反演方法对研究区进行了孔隙度体的反演.经反演发现,较其它反演方法孔隙度体反演剖面分辨率有了很大提高,对薄砂体也能很好地识别,且与井上吻合较好,能很好地刻画出砂体的横向变化情况,平面上砂体的展布也符合该区的沉积相分布.  相似文献   

随机地震反演关键参数优选和效果分析(英文)   总被引：2，自引：0，他引：2  

黄哲远  甘利灯  戴晓峰  李凌高  王军 《应用地球物理》2012,9(1):49-56

随机地震反演技术是将地质统计理论和地震反演相结合的反演方法,它将地震资料、测井资料和地质统计学信息融合为地下模型的后验概率分布,利用马尔科夫链蒙特卡洛(MCMC)方法对该后验概率分布采样,通过综合分析多个采样结果来研究后验概率分布的性质,进而认识地下情况。本文首先介绍了随机地震反演的原理,然后对影响随机地震反演效果的四个关键参数,即地震资料信噪比、变差函数、后验概率分布的样本个数和井网密度进行分析并给出其优化原则。资料分析表明地震资料信噪比控制地震资料和地质统计规律对反演结果的约束程度,变差函数影响反演结果的平滑程度,后验概率分布的样本个数决定样本统计特征的可靠性,而参与反演的井网密度则影响反演的不确定性。最后通过对比试验工区随机地震反演和基于模型的确定性地震反演结果,指出随机地震反演可以给出更符合地下实际情况的模型。  相似文献   

地质统计学在东天山化探信息提取中的应用     

阴江宁  肖克炎  邹伟  王中  路璐 《吉林大学学报(地球科学版)》2012,42(3):887-894

地球化学场和地球物理场都具有一定的空间结构性和空间自相关性,而揭示这种空间相关性的有力工具是变差函数。利用变差函数对东天山的1∶20万区域地球化学数据Cu和Au进行了结构分析。结果表明：两元素在东西方向有着较好的稳定性和连续性,南北方向有较大的变化性并具有一定的线性漂移,总体呈现带状异常,与东天山EW方向大断裂具有很好的一致性。利用泛克里格法对Cu、Au进行了异常信息的提取和评价,泛克里格法提取的剩余异常不仅能突出高异常区,也较清晰地反映了部分低缓异常带,为研究区域化探异常分布特征提供了丰富的信息。  相似文献   

基于多尺度最小二乘支持向量机优化的克里金插值方法     

车磊  王海起  费涛  闫滨  刘玉  桂丽  陈冉  翟文龙 《地球信息科学学报》2017,19(8):1001-1010

克里金插值方法根据待估位置点、已知样本数据点的位置关系和区域化变量的空间相关性,实现空间加权估计,满足估计的无偏性和最优性。传统方法理论模型形状固定且选择具有人为主观性,无法反映空间数据的变化趋势及其空间多尺度特征。本文为解决上述问题,提出了一种基于多尺度最小二乘支持向量机优化的克里金插值方法,此方法为拟合实验变异函数提供了一种新的思路。从实际样本数据的变化趋势出发,采用最小二乘支持向量机拟合实验变异函数,并利用不同尺度小波核反映不同尺度下的空间变化。最后,实验环节包括模拟和应用,模拟主要验证经多尺度最小二乘支持向量机优化后插值方法的科学有效性以及准确性,应用主要研究青岛市PM_2.5浓度时空分布特征,为城市生态科学防护及控制提供理论依据。结果表明,基于多尺度最小二乘支持向量机优化的克里金插值方法能够更好地刻画变异函数,反映不同尺度下的空间变化细节,从而在一定程度上提高插值的精度,是一种可选的克里金插值方法。  相似文献   

Spatial prediction of river channel topography by kriging   总被引：2，自引：0，他引：2  

Carl J. Legleiter  Phaedon C. Kyriakidis 《地球表面变化过程与地形》2008,33(6):841-867

Topographic information is fundamental to geomorphic inquiry, and spatial prediction of bed elevation from irregular survey data is an important component of many reach‐scale studies. Kriging is a geostatistical technique for obtaining these predictions along with measures of their reliability, and this paper outlines a specialized framework intended for application to river channels. Our modular approach includes an algorithm for transforming the coordinates of data and prediction locations to a channel‐centered coordinate system, several different methods of representing the trend component of topographic variation and search strategies that incorporate geomorphic information to determine which survey data are used to make a prediction at a specific location. For example, a relationship between curvature and the lateral position of maximum depth can be used to include cross‐sectional asymmetry in a two‐dimensional trend surface model, and topographic breaklines can be used to restrict which data are retained in a local neighborhood around each prediction location. Using survey data from a restored gravel‐bed river, we demonstrate how transformation to the channel‐centered coordinate system facilitates interpretation of the variogram, a statistical model of reach‐scale spatial structure used in kriging, and how the choice of a trend model affects the variogram of the residuals from that trend. Similarly, we show how decomposing kriging predictions into their trend and residual components can yield useful information on channel morphology. Cross‐validation analyses involving different data configurations and kriging variants indicate that kriging is quite robust and that survey density is the primary control on the accuracy of bed elevation predictions. The root mean‐square error of these predictions is directly proportional to the spacing between surveyed cross‐sections, even in a reconfigured channel with a relatively simple morphology; sophisticated methods of spatial prediction are no substitute for field data. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

IDENTIFICATION OF PALEO-EARTHQUAKES OF LUOYUNSHAN PIEDMONT FAULT BY QUANTITATIVE MORPHOLOGY OF LIMESTONE FAULT SURFACES     

ZOU Jun-jie  HE Hong-lin  SHI Feng  WEI Zhan-yu  SU Peng  YAN Xiao-bing 《地震地质》2019,41(2):400-418

The quantitative analysis of morphologic characteristics of bedrock fault surface is a useful approach to study faulting history and identify paleo-earthquake. It is an effective complement to trenching technique, specially to identifying paleo-earthquakes in a bedrock area where the trenching technique cannot be applied. This paper focuses on the Luoyunshan piedmont fault, which is an active normal fault extending along the eastern boundary of the Shanxi Graben, China. There are a lot of fault scarps along the fault zone, which supply plentiful samples to be selected to our research, that is, to study faulting history and identify paleo-earthquakes in bedrock area by the quantitative analysis of morphologic characteristics of fault surfaces. In this paper, we calculate the 2D fractal dimension of two bedrock fault surfaces on the Luoyunshan piedmont fault in the Shanxi Graben, China using the isotropic empirical variance function, which is a popular method in fractal geometry. Results indicate that the fractal dimension varies systematically with height above the base of the fault surface exposures, indicating segmentation of the fault surface morphology. The 2D fractal dimension on a fault surface shows a ‘stair-like’ vertical segmentation, which is consistent with the weathering band and suggests that those fault surfaces are outcropped due to periodic faulting earthquakes. However, compared to the results of gneiss obtained by the former researchers, the characteristic fractal value of limestone shows an opposite evolution trend. 1)The paleo-earthquake study of the bedrock fault surface can be used as a supplementary method to study the activity history of faults in specific geomorphological regions. It can be used to fill the gaps in the exploration of the paleo-earthquake method in the bedrock area, and then broaden the study of active faults in space and scope. The quantitative analysis of bedrock fault surface morphology is an effective method to study faulting history and identify paleo-earthquake. The quantitative feature analysis method of the bedrock fault surface is a cost-effective method for the study of paleo-earthquakes in the bedrock fault surface. The number of weathered bands and band height can be identified by the segment number and segment height of the characteristic fractal dimension, and then the paleoearthquake events and the co-seismic displacement can be determined; 2)The exposure of the fault surface of the Luoyunshan bedrock is affected and controlled by both fault activity and erosion. A strong fault activity(ruptured earthquake)forms a segment of fault surface which is equivalent to the vertical co-seismic displacement of the earthquake. After the segment is cropped out, it suffers from the same effect of weathering and erosion, and thus this segment has approximately the same fractal dimension. Multiple severe fault activities(ruptured earthquake)form multiple fault surface topography. The long-term erosion under weak hydrodynamic conditions at the base of the fault cliff between two adjacent fault activities(intermittent period)will form a gradual slow-connect region where the fractal dimension gradually changes with the height of the fault surface. Based on the segmentation of quantitative morphology of the two fault surfaces on the Luoyunshan piedmont fault, we identified four earthquake events. Two sets of co-seismic displacement of about 3m and 1m on the fault are obtained; 3)The relationship between the fault surface morphology parameters and the time is described as follows:The fractal dimension of the limestone area decreases with the increase of the exposure time, which reflects the gradual smoothing characteristics after exposed. The phenomenon is opposite to the evolution of the geological features of gneiss faults acquired by the predecessors on the Huoshan piedmont fault; 4)Lithology plays an important role in morphology evolution of fault surface and the two opposite evolution trends of the characteristic fractal value on limestone and gneiss show that the weathering mechanism of limestone is different from that of the gneiss.  相似文献