地震层析成像反演中3种广义解的误差分析与评价   总被引：8，自引：3，他引：5       下载免费PDF全文

常旭  卢孟夏  刘伊克 《地球物理学报》1999,(5):1

在地震波速度和地震波　值层析成像中,对于非线性反演问题解的可靠性研究非常重要．为了讨论ＡＲＴ（ＡｌｇｅｂｒａｉｃＲｅｃｏｎｓｔｒｕｃｔｉｏｎ　Ｔｅｃｈｎｉｑｕｅ）、ＳＶＤ（Ｓｉｎｇｕｌａｒ　ＶａｌｕｅＤｅｃｏｍｐｏｓｉｔｉｏｎ）、ＬＳＱＷ（ＬｅａｓｔＳｕａｒｅ）３种方法的算法稳定性以及反演效果,本研究将这３种算法用于求解非常病态问题和一般稳定问题,根据数值计算结果,分别给出了在非常病态问题和一般稳定问题中３种算法的相对误差及其算法稳定性评价．进而针对３种算法在同一地质模型上的速度成像结果进行了比较,为地震层析成像反演效果分析提供了定量参数．  相似文献   

小波变换多尺度地震波形反演   总被引：29，自引：5，他引：24       下载免费PDF全文

孟鸿鹰  刘贵忠 《地球物理学报》1999,42(2):241-248

完全非线性地震波形反演问题是石油地球物理勘探领域中一个非常重要而又难度很大的问题。本文提出了多尺度地震波形反演的小波变换方法,对于一维非线性地震波形反演问题,将该方法和已有的简单迭代法及多重网格法作了比较,数值实验结果表明,本方法效果较好。  相似文献   

二维视电阻率断面的快速最小二乘反演   总被引：12，自引：0，他引：12  

张大海  王兴泰 《物探化探计算技术》1999,21(1):2-13

快速最小二乘反演是以平滑限定的最小二乘方法为基础,是对二维视电阻率断面进行反演的一种方法。反演过程不需要提供初始模型,在首次迭代时使用一均匀介质地下模型作为初始模型,该模型的视电阻率偏导数值可以用解析法得到。在后面的迭代中,使用了拟牛顿法去修改每一次迭代的偏导数矩阵,避免了偏导数矩阵的直接计算,从而减少了计算时间和存储空间。同时运用牛顿矩阵校正技术解最小二乘方程组也减少了大量的计算时间。总之,该方  相似文献   

Analysis of Heat Budget, Dissipation and Frontogenesis in a Shallow Density Current     

W. Blumen  R. L. Grossman  M. Piper 《Boundary-Layer Meteorology》1999,91(2):281-306

High frequency wind and temperature measurements, obtained in March 1995 from a 10-m tower array situated in south-east Kansas, are used to analyze the structure of a shallow density current. This current is approximately 7 m deep and exhibits a current head that is estimated to be about twice the current depth. The event lasted approximately 900 s and its origin appears to be a shallow slope 2–:5 km to the west of the site, where cold air drainage occurs. The onset of the event is marked by a 5 °C temperature decrease at the 3-m level, increased variance of temperature and of wind velocity, and increased dissipation of kinetic energy, measured by a hot-wire anemometer at the 3-m level. The primary contributors to temperature changes following the frontal passage are both horizontal and vertical advections; contributions from flux divergences of temperature and of radiation, and from dew formation, do not appear to be significant. Postulated frontogenesis, prior to the arrival of the apparent equilibrated front of approximately 176-m width at the site, is examined by means of a theoretical model. The time required to equilibrate the front, by means of kinetic energy dissipation within the frontal zone, is determined to be less than 300 s, or less than the estimated travel time from the orographic slope to the observational site. The absence of upstream data is determined, however, to be a limitation of the analysis performed.  相似文献   

Constraint inversion Algorithm of Lidar Equationfor Deriving Aerosol Optical Property     

邱金桓 《大气科学进展》1999,(2)

1.IntroductionLidarisincreasinglyusedinmeasuringtheopticalpropertiesofaerosolsandcloudssincethe1960's.Ithasbeenshownthatthedeterminationoftheextinctioncoefficientasafunctionofheightisfeasible(Klett,1980;Fernald,1984;LuDarenetal.,1977;Spinhirneetal.,...  相似文献   

安徽沿江地区地壳结构三维空间特征的探讨   总被引：2，自引：0，他引：2  

刘同庆  高尔根  齐文凯  贺传松 《地质与勘探》1999,35(6):48-51

以对扬块区地壳结构总体认识为框架,结合区内构造层以及重、磁等深部地球物理和地震剖面资料,对安徽沿江地区６条剖面进行综合解释和反演拟合,给安徽沿江地区地壳断面的推断结果。  相似文献   

多角度遥感估算稀疏团粒分布型土壤表面粗糙度方法初探     

亢阳卉  王锦地  周红敏  刘艳 《遥感学报》2013,17(1):180-192

表面粗糙度是影响土壤在微波波段发射和散射辐射的主要因素之一,也是微波遥感研究与应用的重要参量。由于微波后向散射还受介电特性、穿透深度等因素的影响,在微波遥感应用中往往难以单独考虑介质表面粗糙度,给参数估算与反演带来了一定困难。在可见光、近红外波段,粗糙度作为土壤表面重要的结构参数之一,直接影响着土壤的二向反射分布特征。因此,本文尝试利用光学多角度观测信息,反演土壤表面粗糙度。基于地表二向反射几何光学模型,假设裸土像元由随机分布于平坦表面的土壤团粒组成,将团粒近似为半椭球体,建立裸露土壤表面二向反射模型,模拟不同粗糙度条件下土壤表面像元的二向反射分布特征。进一步尝试采用多角度观测数据反演模型,估算土壤团粒的几何结构参数,进而计算土壤表面均方根高度,作为表面粗糙度的衡量指标。地面实测多角度数据的初步验证结果表明,多角度光学遥感估算土壤表面粗糙度的方法是可行的。  相似文献   

利用地震面波和重力资料联合反演地壳—上地幔三维密度结构的方法探讨   总被引：2，自引：0，他引：2  

刘崇兵  张禹慎 《测绘学报》1999,28(2):103-109

本文探讨了利用地震面波和重力资料联合反演地壳－地幔三维密度结构的反演问题。首先建立了地震面波和重力资料的观测方程,然后应用广义线性反线理论给出了反演问题的解。模型试验结果表明,与单纯面波反演的结果相比,联合反演的解在分析率和方差两个方面都有改善,当加入扰动重力数据时,在０－３００ｋｍ深度范围内联合反演的结果明显好于单纯面波反演的结果。  相似文献   

一次持续稳定的平流雾天气   总被引：6，自引：1，他引：5  

宋润田  王伟民  郁亚宁 《气象》1999,25(6):19-22

对１９９７年１２月１７￣１９日出现在北京地区的平流雾进行了天气学分析,认为此次平流雾是在较为稳定的华北地形槽弱辐射的大尺度条件下,罕见的逆温顶盖（γ＝５．８４℃／１００ｍ）牢牢地置饱和湿空气于２３９．４ｍ以下北京这种特殊的地形中;地面中尺度辐合线和时空剖面图上风的脉动所产生的２００ｍ以下的小尺度辐合线引起的辐合抬升,有利于饱和湿空气不断在山前平原和谷地得以补充和聚焦,所有这些是构成这次大雾稳定维持  相似文献   

Crustal structure of the Alpine–Pannonian transition zone: a combined seismic and gravity study     

P. Szafián  G. Tari  F. Horváth  S. Cloetingh 《International Journal of Earth Sciences》1999,88(1):98-110

 The crustal structure of the transition zone between the Eastern Alps and the western part of the Pannonian depression (Danube basin) is traditionally interpreted in terms of subvertical Tertiary strike-slip and normal faults separating different Alpine tectonic units. Reevaluation of approximately 4000-km-long hydrocarbon exploration reflection seismic sections and a few deep seismic profiles, together with data from approximately 300 wells, suggests a different structural model. It implies that extensional collapse of the Alpine orogene in the Middle Miocene was controlled by listric normal faults, which usually crosscut Alpine nappes at shallow levels, but at depth merge with overthrust planes separating the different Alpine units. The alternative structural model was tested along a transect across the Danube basin by gravity model calculations, and the results show that the model of low-angle extensional faulting is indeed viable. Regarding the whole lithosphere of the western Pannonian basin, gravity modelling indicates a remarkable asymmetry in the thickness minima of the attenuated crust and upper mantle. The approximately 160 km lateral offset between the two minima suggests that during the Miocene extension of the Pannonian basin detachment of the upper crust from the mantle lithosphere took place along a rheologically weak lower crust. Received: 13 July 1998 / Accepted: 18 March 1999  相似文献