黄渤海风海流的数值计算   总被引：1，自引：0，他引：1  

王宗山  龚滨  李繁华  邹娥梅  徐伯昌 《海洋科学进展》1992,(2)

文中根据美国提供的“综合海洋和大气资料集”(COADS)资料,编制了黄渤海区30a(1950～1979)平均的四季(代表月取2月、5月、8月、11月)海面风场,进而通过二维非线性流体动力学方程组揭示了研究海区的平均风海流的气候学特征及其随季节的变化.  相似文献   

Stochastic modeling based on deterministic formulation: An example   总被引：1，自引：0，他引：1  

G. R. Dargahi-Noubary 《Mathematical Geology》1992,24(2):161-169

In the context of seismology, an example of stochastic modeling on the basis of an established deterministic formulation is presented. The advantages of this approach to modeling over those based solely on statistical fit are discussed. It is demonstrated that the result of applying this procedure is a model whose main parameter has a physical interpretation, and therefore a validation based on criteria other than statistical goodness of fit is also possible. Statistical inference together with some demonstrating examples are also included.  相似文献   

方位—分维估值法   总被引：8，自引：1，他引：7  

孟宪国  周有武 《地球科学》1992,17(1):63-68

  相似文献   

中国北方大陆下的地幔热柱与岩石圈运动   总被引：36，自引：1，他引：35  

邓晋福  赵海玲 《现代地质》1992,6(3):267-274

本文首次提出中国北方大陆下存在一个地幔热柱的论证,并提出亚热柱(sub—plume)的新概念。热柱的中心与边缘部分的隙间熔浆分别为苦橄质玄武岩与碱性玄武岩。在渐新世到中新世约18.4 Ma内,北方大陆以3.26cm/a的速率向东南飘移了约600km,使日本海、渤海—华北平原等脱离热柱。导致晚第三纪日本海扩张的停止,渤海—华北平原等早第三纪火山喷发的突然中止。火山喷发期间,在热柱头部若干个亚热柱的形成,好似若干个“铆钉”穿入岩石圈,有效地阻止了岩石圈的飘移(这时的飘移速率只有0.05cm/a),我们把火山喷发称为固定岩石圈的“铆钉效应”。  相似文献   

INFLUENCE OF THE VERTICAL SHEAR OF ENVIRONMENTAL FLOWS ON TYPHOON MOTION          下载免费PDF全文

Jiang Qun  Dong Keqin 《Acta Meteorologica Sinica》1991,5(2):228-241

Typhoon is regarded as a convergent,modified Rankine vortex.Based on the vorticity equations written attwo levels,higher and lower in the troposphere,typhoon motions are discussed in this study.The analyticalexpressions of vortex motion direction and speed have been derived for simple homogeneous basic flows at twolevels.The expressions indicate that in the easterties,vertical wind shear enhances the steering of east flow,causing the vortex moving westward faster,otherwise,in the westerlies,it reduces the steering of the west flow,causing the vortex moving eastward slower.These results explain theoretically that“cyclones in the easterliesmove to the right of,and faster than the basic flow;conversely,cyclones in the westerlies move to the left of,andslower than the basic flow.”  相似文献   

苏皖北部上元古界划分与对比的探讨     

王翔  王战 《地球科学与环境学报》1991,(4)

本文首次对苏皖北部地区上元古界中已有K-Ar同位素年龄出现的分散及“倒置”现象的原因作了探讨,指出大多数K-Ar年龄由多种因素造成Ar丢失,从而导致不同程度的偏新。因此,这些年龄数据不能代表本区晚元古代沉积岩的真实年龄。作者根据近几年新获得的一些Rb-Sr全岩等时线年龄数据及地壳波浪运动中表现出来的周期性特征,讨论了建立“徐淮系”的可能性及必要性。作者认为,“徐淮系”可以填补青白口系与震旦系之间至少150Ma的沉积缺失。  相似文献   

论西安地裂缝   总被引：5，自引：0，他引：5       下载免费PDF全文

王景明 《地震地质》1989,11(3):85-93

西安地裂缝具定向延伸、多级羽列和成带、等距的分布格局,为水平左旋和南盘依次下落的同步位错。是基底断裂在统一区域应力场作用下,长期蠕动形成的隐伏微细裂缝,在地下水活动的附加作用下显现出来的一系列构造地裂缝。其发生方式为多点双向破裂,发生时间和活动高峰依次由南向北迁移。它们不均匀地蠕滑、时隐时现,有4、20、400和750年四种活动周期,可与渭河盆地的地震活动对应,是区域构造应力场加强的信息  相似文献   

Temporal scaling in river flow: can it be chaotic? / L’invariance d’échelle de l’écoulement fluvial peut-elle être chaotique?     

《水文科学杂志》2013,58(3)

Abstract

Abstract Identification of the presence of scaling in the river flow process has been a challenging problem in hydrology. Studies conducted thus far have viewed this problem essentially from a stochastic perspective, because the river flow process has traditionally been assumed to be a result of a very large number of variables. However, recent studies employing nonlinear deterministic and chaotic dynamic concepts have reported that the river flow process could also be the outcome of a deterministic system with only a few dominant variables. In the wake of such reports, a preliminary attempt is made in this study to investigate the type of scaling behaviour in the river flow process (i.e. chaotic or stochastic). The investigation is limited only to temporal scaling. Flow data of three different scales (daily, 5-day and 7-day) observed in each of three rivers in the USA: the Kentucky River in Kentucky, the Merced River in California and the Stillaguamish River in Washington, are analysed. It is assumed that the dynamic behaviour of the river flow process at these individual scales provides clues about the scaling behaviour between these scales. The correlation dimension is used as an indicator to distinguish between chaotic and stochastic behaviours. The results are mixed with regard to the type of flow behaviour at individual scales and, hence, to the type of scaling behaviour, as some data sets show chaotic behaviour while others show stochastic behaviour. They suggest that characterization (chaotic or stochastic) of river flow should be a necessary first step in any scaling study, as it could provide important information on the appropriate approach for data transformation purposes.  相似文献   

On derivation of EIH (Einstein–Infeld–Hoffman) equations of motion from the linearized metric of general relativity theory     

Victor Brumberg 《Celestial Mechanics and Dynamical Astronomy》2007,99(3):245-252

The half-century old idea of Infeld to use the variational principle of the general relativity field equations is reminded to show that the commonly employed EIH (Einstein–Infeld–Hoffman) equations of motion may be derived from the linearized (weak-field) metric alone. Based on it, the linearized metric might be sufficient for post-Newtonian celestial mechanics and astrometry enabling one to derive the post-Newtonian equations of motion and rotation of celestial bodies as well as the post-Newtonian equations of light propagation within the general relativity framework.  相似文献   

Scaling and self‐similarity in one‐dimensional unsteady open channel flow          下载免费PDF全文

Ali Ercan  M. Levent Kavvas  Ismail Haltas 《水文研究》2014,28(5):2721-2737

The conditions under which the Saint Venant equations system for unsteady open channel flow, as an initial–boundary value problem, becomes self‐similar are investigated by utilizing one‐parameter Lie group of point scaling transformations. One of the advantages of this methodology is that the self‐similarity conditions due to the initial and boundary conditions can also be investigated thoroughly in addition to the conditions due to the governing equation. The obtained self‐similarity conditions are compared with the scaling relationships that are derived through the Froude similitude. It is shown that the initial–boundary value problem of a one‐dimensional unsteady open channel flow process in a prototype domain can be self‐similar with that of several different scaled domains. However, the values of all the flow variables (at specified time and space) under different scaled domains can be upscaled to the same values in the prototype domain (at the corresponding time and space), as shown in this study. Distortion in scales of different space dimensions has been implemented extensively in physical hydraulic modelling, mainly because of cost, space and time limitations. Unlike the traditional approach, the distinction is made between the longitudinal–horizontal and transverse–horizontal length scales in this study. The scaled domain obtained by the proposed approach, when scaling ratios of channel width and water depth are equal, is particularly important for the similarity of flow characteristics in a cross‐section because the width‐to‐depth ratio and the inclination angles of the banks are conserved in a cross‐section. It is also shown that the scaling ratio of the roughness coefficient under distorted channel conditions depends on that of hydraulic radius and longitudinal length. The proposed scaling relations obtained by the Lie group scaling approach may provide additional spatial, temporal and economical flexibility in setting up physical hydraulic models. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献