长江口九段沙下段冲淤演变水动力机制分析   总被引：5，自引：0，他引：5       下载免费PDF全文

徐福敏  严以新  茅丽华 《水科学进展》2002,13(2):166-171

概述了长江口深水航道整治一期工程及工程对九段沙下段地形冲淤的影响.根据已建立的σ坐标系下三维非线性水流数学模型,用新测水文资料对模型进行验证.利用所建立的模型,结合由现场测量得到一期工程前后九段沙下段近期地形演变,数值模拟了北槽区域流通量、底层欧拉余流和北槽中下段平面水流特征,以综合分析北槽水域水动力变化对九段沙下段地形冲淤变化的影响.  相似文献   

Synoptic circulation and stream discharge in the Great Lakes basin, USA     

R. V. Rohli  A. J. Vega  M. R. Binkley  S. D. Britton  H. E. Heckman  J. M. Jenkins  Y. Ono  D. E. Sheeler 《Applied geography (Sevenoaks, England)》2001,21(4)

Impacts on water resources caused by human activity, natural climate variation and long-term climate change are unclear in the US Great Lakes region. Improved understanding of the impact of atmospheric circulation on stream discharge variability into the Lakes is thus important. In this analysis, monthly surface and mid-tropospheric circulation patterns suggest that surface pressure variations over Missouri and Illinois are most strongly correlated to discharge. The mid-tropospheric patterns most directly related to discharge place the Great Lakes in a trough-to-ridge flow pattern. The analysis confirms that at this scale, lee shore advection resulting in ‘lake-effect’ precipitation is not very important to regional discharge, and neither are variations in the Pacific–North American teleconnection.  相似文献   

贵州岩溶水充水矿井涌水量预测探讨     

刘前明 《中国煤田地质》2001,13(2):97-98

贵州绝大多数煤矿井是以岩溶水充水为主，矿井排水量与大气降水密切，地面塌陷与淹井事故也屡见不鲜，因此矿井涌水量预测是个非常复杂的问题，作者根据在本地工作的多年工作经验，介绍了一种适用的简易的矿井涌水量与突水量计算方法。  相似文献   

EFFECTIVE DISCHARGE CALCULATION GUIDE     

D. S. BIEDENHARN  C. R. THORNE  P.J.SOAR.  R.D.HEY  and C. C. WATSONS Engineer  U.S. Army Corps of Engineers  Waterways Experiment Station  Vicksburg  MS  USA. Professor School of Geography  University of Nottingham  Nottingham NG RD  UK. Prof 《国际泥沙研究》2001,16(4)

1 mTRonvcnox: moareS Aun CoxcmSAJluvial rivers have the pOtenhal to adjust their shaPe and dimensions to all flows that tranSPOrtsediment, but Inglis (l94l) suggested that, for rivers that are in regime, a single steady flow could beidenhfied which would Produce the same bankfll dimensions as the natural sequence of events. Hereferrd to this now as the dondnan discharge.Wolman and Mller (l960) idenhfied that the flow doing most bed material transPort over a period ofyears may be taken tO…  相似文献   

下庄铀成矿古水热系统排泄区（减压区）铀成矿作用研究     

刘金辉  李学礼 《矿床地质》2001,20(3):259-264

形成于古水热系统排泄区（减压区）的下庄花岗岩型铀矿床是地下热水与岩石相互作用的产物。矿物流体包裹体水文地球化学分析表明，成矿期铀成矿古热水溶液气体成分主要为CO2，水化学类型为HCO3－Ca.Na型，F－Ca型和HCO3.F－K型。地球化学模式和热力学计算证明，热水溶液中铀的存在形式为UO2（CO3）2^2-,UO2F3^-和UO2F4^2-。热水溶液深循环过程中CO2的加入可使溶液铀沉淀临界电位值（EhC,U)明显降低，从而保持水－铀比电位值（ΔEhW,U)为正值（ΔEhW,U=EhW-EhC,U)使铀在深部相对还原的条件下仍能稳定迁移。当富铀成矿热液进入减压排泄区时，由于溶液物理－化学条件的改变，发生CO2脱气作用和中和还原作用，导致ΔEhW,U小于零，使铀沉淀、富集，最终形成花岗岩型铀矿床。  相似文献   

新疆头屯河流域水沙特性与减沙治理   总被引：2，自引：0，他引：2  

陈亚宁  汪雄祥 《干旱区地理》1996,19(2):37-43

本文通过对头屯河流域山区各水文实测水文，泥沙资料的分析比较，揭示了头屯河水沙运移规律，指出了头屯河上游产水，中游产沙，水沙异源的特点，进而地实才考察测量的基础上，结合流域自然特点，提出了工程，生物措施相结合的减沙治理方案和在流域不同地段的具本治理措施。  相似文献   

前汛期北江洪水过程水汽汇与河水流量的关系   总被引：4，自引：0，他引：4  

简茂球  罗会邦 《热带地理》1996,16(2):130-135

本文分析了１９８０－１９８４年４－６月和１９９４年６月洪水过程北江流域的大气水汽汇特征及其与河水流量的关系。结果表明：前汛期洪水过程的前期大乞一般连续存在超过一定值的较强水汽汇，时间为１周左右，洪水的发生是强水汽汇连续产生的径流的积累所致；北江流域洪水期水汽汇的极大峰一般比石角站的洪峰流量超前２天左右，本文结果为洪水的预报提供一条新思路。  相似文献   

An experimental study of sapped drainage network development     

Basil Gomez  Victor T. Mullen 《地球表面变化过程与地形》1992,17(5):465-476

In a basin developed on a stream table, effluent subsurface flow supported a channel network that evolved by a combination of headward growth, lateral widening and divide decay. The area occupied by the developing network increased with time. Circularity was used to characterize network evolution which occurred in three phases (initiation, extension and abstraction). Basin sediment discharge declined exponentially with time. Pronounced quasi-cyclic variability was superimposed upon this general trend. Some of the variability was directly linked to changes in the amount of sediment supplied to the channel. The variation of mean network sediment yield (mean sediment discharge scaled by network area) with time adequately described the general decline in sediment discharge as the network evolved.  相似文献   

Estimation of the transfer function by autoregressive deconvolution techniques—An application to time series analysis     

Y. S. Kang  J. J. Royer  Cl. Chambon  L. Demassieux 《Mathematical Geology》1992,24(5):479-498

The transfer function of time-dependent models is classically inferred by the ordinary least squares (OLS) techniques. This OLS technique assumes independence of the residuals with time. However, in practical cases, this hypothesis is often not justified producing inefficient estimation of the transfer function. When the residuals constitute an autoregressive process, we propose to apply the Box-Jenkins' method to model the residuals, and to modify in a simple manner the primary convolution equation. Then, a multivariate regression technique is used to infer the transfer function of the new equation producing time-independent residuals. This three-step autoregressive deconvolution technique is particularly efficient for time series analysis. The reconstitution and the forecasting of real data are improved efficiently. Theoretically, the proposed method can be extended to the convolution equations for which the residuals follow a moving average or an autoregressive-moving average process, but the mathematical formulation is no longer direct and explicit. For this general case, we propose to approximate the moving average or the autoregressive-moving average process by an autoregressive process of sufficient order, and then the transfer function. Two case studies in hydrogeology will be used to illustrate the procedure.  相似文献   

黄河下游的河性   总被引：8，自引：0，他引：8  

尹学良  陈金荣 《地理学报》1992,47(3):193-207

本文探讨了黄河一般特性的综合关系,讨论了河道演变中均衡与非均衡的问题、滩槽冲淤的利与害和主与从的问题,同时讨论了河道冲淤演变特性、与水沙条件的关系、河槽淤积率和淤积比等。  相似文献