Comparative analysis of relationships between NLDAS‐2 forcings and model outputs     

Youlong Xia  Mike Ek  Helin Wei  Jesse Meng 《水文研究》2012,26(3):467-474

This study reports results from an analysis of the relationship between atmospheric forcing and model‐simulated water and energy fluxes for the North American Land Data Assimilation System Project Phase 2 (NLDAS‐2). The relationships between mean monthly precipitation and total runoff are stronger in the Sacramento (SAC) and variable infiltration capacity (VIC) models, which grew out of the hydrological community, than in the Noah and Mosaic models, which grew out of the soil‐vegetation‐atmosphere transfer (SVAT) community. The reverse is true for the relationship between mean monthly precipitation and evapotranspiration. In addition, surface energy fluxes in VIC are less sensitive to model forcing (except for air temperature) than those in the Noah and Mosaic model. Notwithstanding these general conclusions, the relationships between forcings and model‐simulated water and energy fluxes for all models vary for different seasons, variables, and regions. These findings will ultimately inspire a combination of SVAT‐type model energy components with hydrological model water components to develop a SVAT‐hydrology model to improve both evapotranspiration and total runoff simulations. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Spatial proximity of age-0 walleye pollock (Theragra chalcogramma) to zooplankton near the Pribilof Islands, Bering Sea, Alaska     

Swartzman  G.; Brodeur  R.; Napp  J.; Hunt  G.; Demer  D.; Hewitt  R. 《ICES Journal of Marine Science》1999,56(4):545-560

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航磁概查对青藏高原一些地质问题的新认识   总被引：3，自引：7，他引：3  

周伏洪  姚正煦  薛典军  刘振军  张永军 《物探与化探》2001,25(2):81-89

根据青藏高原中西部1:100万航磁概查结果,对雅鲁藏布江缝合带、塔里木盆地南部边界、高原内部几条规模较大断裂和区域性负磁异常带等高原地区几个有关的地质和地球物理问题进行了解释和探讨,获得了与以往不同的认识,这对青藏高原的深入研究具有重要意义。同时,也表明了通过航磁概查所获得的青藏高原中西部最新航磁图用于地质问题的研究具有很好的效果。  相似文献   

华北晚古生代成煤环境与成煤模式多样性研究   总被引：23，自引：2，他引：23  

桑树勋  陈世悦  刘焕杰 《地质科学》2001,36(2):212-221

华北晚古生代聚煤盆地存在活动体系成煤环境和废弃体系成煤环境。前者的海相成煤环境主要为泻湖泥炭坪,陆相成煤环境以三角洲平原沼泽意义最大。晚石炭世至晚二叠世,海相为主的成煤环境逐渐被陆相为主的成煤环境所取代,由盆缘到盆内成煤环境总体呈环带状展布。成煤环境差异性影响了成煤特点,这些成煤特点成为识别海、陆相煤层的显著相标志。华北晚古生代聚煤盆地在时间上和空间上存在成煤模式的多样性,以陆表海滨岸成煤模式、废弃碎屑体系成煤模式和浅水三角洲成煤模式为主。  相似文献   

Generalized minimum variance control for buildings under seismic ground motion     

L. Guenfaf  M. Djebiri  M. S. Boucherit  F. Boudjema 《地震工程与结构动力学》2001,30(7):945-960

The generalized minimum variance (GMV) algorithm for the control of civil engineering structures is developed and presented in this paper. This algorithm needs the knowledge of the seismic excitation model to derive the autoregressive moving average exogen model of the structure. Then the GMV control is applied. The control is designed such that the variance of the generalized cost function is minimized. To demonstrate the effectiveness of this control technique, simulation tests using a single‐degree‐of‐freedom structure are performed. The results show that the relative displacement of the structure and the control effort are significantly reduced. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Which Models for Collocated Cokriging?   总被引：1，自引：0，他引：1  

Jacques Rivoirard 《Mathematical Geology》2001,33(2):117-131

When a target variable is sparsely sampled, compared to a densely sampled auxiliary variable, cokriging requires simplifications. In its strict sense, collocated cokriging makes use of the auxiliary variable only at the current point where the target variable is to be estimated; in the multicollocated form, it also makes use of the auxiliary variable at all points where the target variable is available. This paper looks for the models that support these collocated cokrigings, i.e., the models in which the simplification resulting from the collocated forms does not result in any loss of information. In these models, the cross-structure between the two variables is shown to be proportional to the structure of the auxiliary variable, not to the structure of the target variable as is often assumed (except, of course, when all structures are proportional). The target variable depends on the auxiliary variable and on a spatially uncorrelated residual. Collocated cokriging simplifies to the simple method, which consists in kriging this residual. The strictly collocated cokriging corresponds to the particular case where the residual has a pure nugget structure, but it is then reduced to the single regression at the target point. Except for this trivial case, there are no models in which strictly collocated cokriging is exactly a cokriging.  相似文献   

资源与环境模型标准文档库及其与GIS集成   总被引：20，自引：1，他引：20  

岳天祥 《地理学报》2001,56(1):107-112

论述了中国资源与环境模型标准文档库的结构和内容。通过研究总结数学模型及其研究现状发现，中国资源与环境模型标准文档库建设需要完善尚有缺陷的数学模型、创建尚缺少的数学模型；通过归纳现有数学模型与地理信息系统的现有集成方法发现，目前的集成方法不能满足区域可持续发展集成模型的需要，据此讨论了数学模型与地理信息系统有效集成需要深入研究的内容。最后，提出了通过大量案例研究，形成区域可持续发展集成模型和中国资源与环境模型标准文档库2个软件包的可行研究思路。  相似文献   

动态平差概括模型与假设检验     

李明峰  於宗俦  李延兴  于正林 《武汉大学学报(信息科学版)》1995,(3)

建立了包括各种静态平差模型和线性动态平差模型的动态平差概括模型，推导了其主要求解公式。对动态平差概括模型下的形变检验和形变与粗差的可区分性检验作了公式推导和理论分析，丰富了形变监测数据处理理论。  相似文献   

地震学中非线性预测方法的初步研究   总被引：2，自引：0，他引：2  

石特临  郭大庆 《地球科学进展》1995,10(3):273-277

介绍了近年来地震预测学中非线性理论和非线性方法的研究趋势和最新研究进展。在非线性数学模型的研究中，较为成功地将非线性门限模型，指数模型、具有长程关联自回归模型等应用于地震的中期预测上，在分形研究上，明确地取代了以往的一些经验结果，使对地震的活动的经验统计关系上升到分形的理论，在研究地震的动力学机制中，以多滑块－弹簧模型为代表，模拟地壳上地震断层运动机制和事实，建立了粘滑摩擦情况下的参数动力学方程。  相似文献   

Approximate local confidence intervals under change of support     

A. E. Tercan  P. A. Dowd 《Mathematical Geology》1995,27(1):149-172

Approximate local confidence intervals are constructed from uncertainty models in the form of the conditional distribution of the random variable Z given values of variables [Z_i, i=1,...,n]. When the support of the variable Z is any support other than that of the data, the conditional distributions require a change of support correction. This paper investigates the effect of change of support on the approximate local confidence intervals constructed by cumulative indicator kriging, class indicator kriging, and probability kriging under a variety of conditions. The conditions are generated by three simulated deposits with grade distributions of successively higher degree of skewness; a point support and two different block supports are considered. The paper also compares the confidence intervals obtained from these methods using the most used measures of confidence interval effectiveness.  相似文献