A Numerical Study on Effects of Land-Surface Heterogeneity from ‘Combined Approach’ on Atmospheric Process Part II: Coupling-Model Simulations     

Zeng Xinmin  Zhao Ming  Su Bingkai 《大气科学进展》2000,17(2):241-255

1.IntroductionInthecompanionPaper(hereafterreferredtoas299),wecombinedthemosaicapproachandtheanalyticaltypeofstatistical--dynamicalapproach,andproPOsedaacombinedapProach",whichcouldrepresentbothinterpatchvariabilityandintrapatchvariabilityaswellascomputationallycostless.Aftertheheterogeneityoftheroughnesslengthic(or/andzeroplanedisplacementheightd,)isconsideredbythecombinedapproachinBiosphere/AtmosphereTransferSchemeVersionie(BATSie)(Dickinsonetal.,1993),expressions,suchasdragcoefficienta…  相似文献   

A MULTI-WINDOW GIS APPROACH FOR WATER QUALITY DATA ANALYSIS     

Lin Hui 《中国地理科学(英文版)》1995,5(3):257-264

ＡＭＵＬＴＩ－ＷＩＮＤＯＷＧＩＳＡＰＰＲＯＡＣＨＦＯＲＷＡＴＥＲＱＵＡＬＩＴＹＤＡＴＡＡＮＡＬＹＳＩＳＬｉｎＨｕｉ（ＤｅｐａｒｔｍｅｎｔｏｆＧｅｏｇｒａｐｈｙ，ＴｈｅＣｈｉｎｅｓｅＵｎｉｖｅｒｓｉｔｙｏｆＨｏｎｇＫｏｎｇ，Ｓｈａｔｉｎ，ＮｅｗＴｅｒｒ...  相似文献   

震源体破裂行为的重整化群方法研究   总被引：2，自引：0，他引：2  

杨国栋  郭大庆 《华南地震》1997,17(2):1-8

应用重整化群方法对一维、二维和三维震源体的破裂问题进行了研究，得到了一维、二维和三辰原体破裂的临界概率值分别国０．２０６３、０．１７０７和０．１５９９，相关长度指数分别为１．４３８８、０．８０８４和０．５７５７。进而由此揭示了临界概率和相关长度指数随维数增大而减少的变化规律。  相似文献   

近岸水平场地液化侧向大变形机理及软化模量分析方法   总被引：3，自引：1，他引：3  

蔡晓光  袁晓铭  刘汉龙  孙锐  周静 《地震工程与工程振动》2005,25(3):125-131

本文依据震害现象和实验探讨近岸水平场地地面液化侧向大变形机理，改进现有软化模量分析技术，给出一套地面液化侧向大变形的分析方法。近岸水平场地侧向大变形机理因地基中孔隙水压力升高、土体模量衰减、土骨架变软使偏应变得到充分发展所致，其水平永久侧移可用从底部到顶部呈增加形式的整体变形描述。利用本文方法，对1995年阪神地震中近岸沉箱岸壁和土体液化侧向大变形进行了数值模拟，结果与震后实测结果和试验结果在主要特征上一致，说明改进的软化模量法可以用于地面液化侧向大变形的分析。  相似文献   

压制地震资料中工业电干扰的 余弦逼近法的改进及应用   总被引：1，自引：0，他引：1  

胡伟  吕小伟 《物探与化探》2005,29(6):537-540

在对实际资料分析的基础上, 笔者提出对工业电干扰频率进行精细扫描、标准余弦信号超采样及深层振幅统计等方法对目前常用的余弦逼近法进行改进, 理论分析及实际资料的处理结果对比表明了改进后的方法更实用、精度更高。  相似文献   

Scaling dimensions in spectroscopy of soil and vegetation     

《International Journal of Applied Earth Observation and Geoinformation》2007,9(2):137-164

The paper revises and clarifies definitions of the term scale and scaling conversions for imaging spectroscopy of soil and vegetation. We demonstrate a new four-dimensional scale concept that includes not only spatial but also the spectral, directional and temporal components. Three scaling remote sensing techniques are reviewed: (1) radiative transfer, (2) spectral (un)mixing, and (3) data fusion. Relevant case studies are given in the context of their up- and/or down-scaling abilities over the soil/vegetation surfaces and a multi-source approach is proposed for their integration.Radiative transfer (RT) models are described to show their capacity for spatial, spectral up-scaling, and directional down-scaling within a heterogeneous environment. Spectral information and spectral derivatives, like vegetation indices (e.g. TCARI/OSAVI), can be scaled and even tested by their means. Radiative transfer of an experimental Norway spruce (Picea abies (L.) Karst.) research plot in the Czech Republic was simulated by the Discrete Anisotropic Radiative Transfer (DART) model to prove relevance of the correct object optical properties scaled up to image data at two different spatial resolutions. Interconnection of the successive modelling levels in vegetation is shown. A future development in measurement and simulation of the leaf directional spectral properties is discussed.We describe linear and/or non-linear spectral mixing techniques and unmixing methods that demonstrate spatial down-scaling. Relevance of proper selection or acquisition of the spectral endmembers using spectral libraries, field measurements, and pure pixels of the hyperspectral image is highlighted. An extensive list of advanced unmixing techniques, a particular example of unmixing a reflective optics system imaging spectrometer (ROSIS) image from Spain, and examples of other mixture applications give insight into the present status of scaling capabilities.Simultaneous spatial and temporal down-scaling by means of a data fusion technique is described. A demonstrative example is given for the moderate resolution imaging spectroradiometer (MODIS) and LANDSAT Thematic Mapper (TM) data from Brazil. Corresponding spectral bands of both sensors were fused via a pyramidal wavelet transform in Fourier space. New spectral and temporal information of the resultant image can be used for thematic classification or qualitative mapping.All three described scaling techniques can be integrated as the relevant methodological steps within a complex multi-source approach. We present this concept of combining numerous optical remote sensing data and methods to generate inputs for ecosystem process models.  相似文献   

Undiscovered Petroleum Accumulation Mapping Using Model-Based Stochastic Simulation   总被引：7，自引：0，他引：7  

Zhuoheng Chen  Kirk G. Osadetz 《Mathematical Geology》2006,38(1):1-16

Stochastic simulation has been proven to be a useful tool for revealing uncertainties in petroleum exploration and exploitation. The application to petroleum resource assessment would result in predicted potential accumulations with geographic locations, a desirable feature for improving both resource management and exploration efficiency. The associated uncertainties with the prediction provide information useful for exploration risk analysis. This attempt has been encumbered by two typical technical difficulties: biased observation data and lack of information with respect to the undiscovered accumulation locations. In this paper we propose a model-based simulation approach, in which models are used to perform unbiased parameter estimation from biased data and to facilitate the location of undiscovered petroleum accumulations based on reasoning of available geological and geophysical observations. The Fourier transform algorithm is chosen for the simulation because the spatial correlation and location-specific features can be studied separately from different data sources and integrated in the simulation in a frequency domain. The proposed approach is illustrated by an example from the Rainbow petroleum play in the West Canadian Sedimentary Basin. In the application example, a pre-1994 exploration history data set was used as input, and the predictions are then checked against the locations of post-1993 exploratory drilling results. The comparison of the predictions from the proposed approach and the traditional conditional simulation shows that the model-based approach captures the essentials of geological controls on the spatial distribution of petroleum accumulation, thus improving the projections of undiscovered petroleum accumulations.  相似文献   

Human exposure to mercury as a consequence of landscape management and socio-economical behaviors： Three case studies in Canada     

《中国地球化学学报》2006,25(B08):242-243

In direct continuation with the acquired knowledge of ecosystem approach for the presence of mercury in the Amazon, we have launched in 2001 the NSERC-supported pan-Canadian COMERN project. This Collaborative Mercury Research Network addresses the urgent need for the development of a framework enabling researchers, political stakeholders, and communities concerned by the mercury question to evolve towards an interdisciplinary association capable of synergistically combining our knowledge on Hg into an original synthesis. We are presenting a simple integrated indicator representative of the specific susceptibility of an ecosystem to Hg bioaccumulation and subsequent transfer to humans. This indicator includes three concepts： （1） the sensitivity to bioaccumulation, induced and influenced by factors such as the Hg loading, the different transport and methylation processes, and human activities; （2） the vulnerability of the populations exposed to Hg through consumption of local and market fish; and （3） the adaptability of the ecosystem and the people living into it, an evaluation of its resilience, or its capacity to recover and/or to cope with the contamination, taking into account the social and political resources within the communities impacted.  相似文献   

岩溶地区地下水防污性能评价——PI方法   总被引：2，自引：0，他引：2  

徐慧珍  高赞东 《新疆地质》2006,24(3):318-321

地下水防污性能评价是保护地下水资源的有效工具.国内外专家进行了许多研究,提出了多种地下水防污性能评价模型,最常用的是DRASTIC模型.但这些模型主要适用于孔隙水地区,对岩溶地区的适应性差.为了研究岩溶地区地下水防污性能,欧洲专家提出了欧洲方法(Europeanapproach).在欧洲方法这个概念模型的基础上,学者提出了多种岩溶地区地下水防污性能评价方法,如PI方法、VULK方法、LEA方法、COP方法和Time-Input方法.本文主要对PI方法进行了较详细的介绍,并指出应用该方法时应注意的问题.  相似文献   

Analytical approach for the toroidal relaxation of viscoelastic earth   总被引：1，自引：0，他引：1  

Hansheng Wang  Patrick Wu 《Geophysical Journal International》2006,167(1):1-19

This paper is concerned with post-seismic toroidal deformation in a spherically symmetric, non-rotating, linear-viscoelastic, isotropic Maxwell earth model. Analytical expressions for characteristic relaxation times and relaxation strengths are found for viscoelastic toroidal deformation, associated with surface tangential stress, when there are two to five layers between the core–mantle boundary and Earth's surface. The multilayered models can include lithosphere, asthenosphere, upper and lower mantles and even low-viscosity ductile layer in the lithosphere. The analytical approach is self-consistent in that the Heaviside isostatic solution agrees with fluid limit. The analytical solution can be used for high-precision simulation of the toroidal relaxation in five-layer earths and the results can also be considered as a benchmark for numerical methods. Analytical solution gives only stable decaying modes—unstable mode, conjugate complex mode and modes of relevant poles with orders larger than 1, are all excluded, and the total number of modes is found to be just the number of viscoelastic layers between the core–mantle boundary and Earth's surface—however, any elastic layer between two viscoelastic layers is also counted. This confirms previous finding where numerical method (i.e. propagator matrix method) is used. We have studied the relaxation times of a lot of models and found the propagator matrix method to agree very well with those from analytical results. In addition, the asthenosphere and lithospheric ductile layer are found to have large effects on the amplitude of post-seismic deformation. This also confirms the findings of previous works.  相似文献