水文时间序列趋势和跳跃分析的再抽样方法研究   总被引：3，自引：0，他引：3  

刘攀  郭生练  肖义  李玮  郭富强 《水文》2007,27(2):49-53

用再抽样方法估计水文时间序列趋势或跳跃的显著性水平,可通过分块的方法消除水文时间序列自相关性的干扰,具有直接、精确的优点。介绍了再抽样方法在水文时间序列趋势和跳跃分析中的原理与方法;针对黄河三门峡水文站1919～1989年实测年径流量资料,采用几种常用的参数和非参数统计量,用再抽样方法进行了实例研究,其中采用滑动分块自助法以消除自相关性的干扰,该方法为估计水文时间序列的趋势、跳跃的显著性水平给出了新的思路与途径。  相似文献   

Study of shallow groundwater quality evolution under saline intrusion with environmental isotopes and geochemistry   总被引：2，自引：0，他引：2  

F. Ma  Y. S. Yang  R. Yuan  Z. Cai  S. Pan 《Environmental Geology》2007,51(6):1009-1017

Evolution of the shallow groundwater quality under saline intrusion in porous aquifer system has been studied with environmental isotopes and geochemistry in the Laizhou Bay area, China. Two campaigns of water sampling from various sources were carried out in spring and winter for environmental isotopic and chemical analyses. The origin of groundwater salinity from intrusion of both modern seawater and deep brine water was identified by analysing the correlations between ¹⁸O, D, T, Cl⁻, SO₄²⁻ and electrical conductivity. The results indicate that the brine is originated from evaporating and concentrating of intruded seawater and its δD and δ¹⁸O are different from modern seawater but similar to those of mixture of seawater with fresh groundwater. It is hard to distinguish the salinity origin in this area by the δD–δ¹⁸O relationship alone. The relations between δ¹⁸O and conductivity, Cl⁻ and SO₄²⁻ have been used to identify the salinity origin due to the distinct difference in salinity between the brine and seawater, conjunctively with use of T. A threshold of T = 12 TU was adopted to identify the origin of saline groundwater.  相似文献   

梯级水库群联合优化调度函数研究   总被引：6，自引：3，他引：6       下载免费PDF全文

刘攀  郭生练  张文选  肖义  高仕春 《水科学进展》2007,18(6):816-822

构建了制定梯级水库群联合优化调度函数的"优化-拟合-再优化-随机仿真"框架:首先建立梯级水库群优化调度模型,通过确定性动态规划方法得到最优样本;然后对最优样本进行多元线性回归分析得到联合调度函数;并基于模拟调度结果采用非线性规划方法直接修正调度函数;最后通过水文随机模拟技术生成径流系列,进一步检验、评价所得调度函数的效率。以清江梯级水库群长期优化调度为对象进行实例研究,计算结果表明:对于1951-2005年实测径流系列,梯级水库群联合优化调度函数较常规调度方案年均增加发电量2.03亿kW·h,增幅达2.79%;对于两种随机模拟方法生成的水文径流系列,年均发电量分别提高了1.74%和2.36%,经济效益显著。  相似文献   

利用井径资料预测鱼卡煤田东部勘探区七煤顶板的稳定性     

栾安辉潘语录  田贵发 《中国煤田地质》2007,19(6):73-75

在煤田测井中，井径的变化对其它测井参数是一种干扰，但利用井径的相对变化值（井径扩大系数），可有效地评估岩石的强度等级和可采煤层顶底板的稳定性。统计鱼卡煤田东部勘探区29个钻孔孔径的变化值，按岩石抗压强度划分原则，将其七煤顶板稳定性划分为5个等级，据此固定了该煤田七煤顶板稳定性分布图。  相似文献   

Field and geochemical characteristics of the Mesoarchean ( 3075 Ma) Ivisaartoq greenstone belt, southern West Greenland: Evidence for seafloor hydrothermal alteration in supra-subduction oceanic crust     

Ali Polat  Peter W.U. Appel  Robert Frei  Yuanming Pan  Y&#x;ld&#x;r&#x;m Dilek  Juan C. Ordez-Caldern  Brian Fryer  Julie A. Hollis  Johann G. Raith 《Gondwana Research》2007,11(1-2):69

The Mesoarchean (ca. 3075 Ma) Ivisaartoq greenstone belt in southern West Greenland includes variably deformed and metamorphosed pillow basalts, ultramafic flows (picrites), serpentinized ultramafic rocks, gabbros, sulphide-rich siliceous layers, and minor siliciclastic sedimentary rocks. Primary magmatic features such as concentric cooling-cracks and drainage cavities in pillows, volcanic breccia, ocelli interpreted as liquid immiscibility textures in pillows and gabbros, magmatic layering in gabbros, and clinopyroxene cumulates in ultramafic flows are well preserved in low-strain domains. The belt underwent at least two stages of calc-silicate metasomatic alteration and polyphase deformation between 2963 and 3075 Ma. The stage I metasomatic assemblage is composed predominantly of epidote (now mostly diopside) + quartz + plagioclase ± hornblende ± scapolite, and occurs mainly in pillow cores, pillow interstitials, and along pillow basalt-gabbro contacts. The origin of this metasomatic assemblage is attributed to seafloor hydrothermal alteration. On the basis of the common presence of epidote inclusions in diopside and the local occurrence of epidote-rich aggregates, the stage I metasomatic assemblage is interpreted as relict epidosite. The stage II metasomatic assemblage occurs as concordant discontinuous layered calc-silicate bodies to discordant calc-silicate veins commonly associated with shear zones. The stage II metasomatic assemblage consists mainly of diopside + garnet + amphibole + plagioclase + quartz ± vesuvianite ± scapolite ± epidote ± titanite ± calcite ± scheelite. Given that the second stage of metasomatism is closely associated with shear zones and replaced rocks with an early metamorphic fabric, its origin is attributed to regional dynamothermal metamorphism. The least altered pillow basalts, picrites, gabbros, and diorites are characterized by LREE-enriched, near-flat HREE, and HFSE (especially Nb)-depleted trace element patterns, indicating a subduction zone geochemical signature. Ultramafic pillows and cumulates display large positive initial ε_Nd values of + 1.3 to + 5.0, consistent with a strongly depleted mantle source. Given the geological similarities between the Ivisaartoq greenstone belt and Phanerozoic forearc ophiolites, we suggest that the Ivisaartoq greenstone belt represents Mesoarchean supra-subduction zone oceanic crust.  相似文献   

1999年9月14日和11月30日四川绵竹两次5.0级地震预报     

潘正权  邹文发  潘石瑛 《地震地磁观测与研究》2007,28(1):30-36

1999年在四川省德阳市绵竹县发生了两次5.0级地震.其中1999年11月30日绵竹汉旺5.0级地震前,德阳市地震局对该次地震的时问、地区、震级三要素做出了准确的短临预报.该项预报在人口稠密经济发达的四川德阳地区成功实现,取得了良好的社会和经济效益,得到了中国地震局,德阳市人民政府的充分肯定,并予以表彰和奖励.  相似文献   

石狮市基础控制网探讨     

潘志华 《测绘技术装备》2007,9(1):33-34,16

随着国民经济建设的高速发展与现代测绘技术的迅猛发展,石狮市现有的大地控制成果无论在其精度与现势性方面均无法满足城市建设的需要,为解决急需,充分发挥基础控制网在国民经济建设基础与先行作用,迫切需要加强石狮市基础测绘工作。本文根据现代测绘技术结合石狮市基础控制网发展要求,对石狮市基础控制网,包括控制基准、大地水准面精化等进行系统研讨,为项目实施提供参考。  相似文献   

阿尼玛卿缝合带东段上地壳结构-马尔康-碌曲-古浪深地震测深剖面结果   总被引：3，自引：1，他引：3       下载免费PDF全文

张先康  杨卓欣  徐朝繁  潘纪顺  刘志  王夫运  嘉世旭  赵金仁  张成科  孙国伟 《地震学报》2007,29(6):592-604

位于青藏高原东北缘川北甘南地区的马尔康——碌曲——古浪深地震测深剖面穿越阿尼玛卿缝合带东段，利用该剖面获得的Pg, Sg初至折射波资料，采用有限差分成像、射线追踪反演、时间项反演和走时曲线分析等方法，对阿尼玛卿缝合带东段及其两侧的上地壳结构进行了分析. 结果表明， 研究区基底变化较大. 由南向北，基底在若尔盖盆地呈稳定的上隆状态，在阿尼玛卿缝合带内强烈下陷，在缝合带北侧一定范围内隆升之后，向北呈下陷趋势. 阿尼玛卿缝合带相对两侧整体表现为南倾的低速带结构，且内部速度存在非均匀性. 库赛湖——玛沁断裂、武都——迭部断裂和舟曲——两当断裂均表现为不同规模的低速带. 库赛湖-玛沁断裂和舟曲——两当断裂位置处基底界面埋深有明显变化，是区隔阿尼玛卿缝合带南北两侧的主要断裂. 武都——迭部断裂发生在基底界面深度变化带上，它与舟曲——两当断裂可能具有同一深部构造背景. 阿尼玛卿缝合带所呈现的强烈下陷的基底低速结构和非均匀性体现了上地壳受挤压的破碎结构特征.   相似文献   

Multiobjective heuristic approaches to seismic design of steel frames with standard sections     

M. Ohsaki  T. Kinoshita  P. Pan 《地震工程与结构动力学》2007,36(11):1481-1495

Seismic design problem of a steel moment‐resisting frame is formulated as a multiobjective programming problem. The total structural (material) volume and the plastic dissipated energy at the collapse state against severe seismic motions are considered as performance measures. Geometrically nonlinear inelastic time‐history analysis is carried out against recorded ground motions that are incrementally scaled to reach the predefined collapse state. The frame members are chosen from the lists of the available standard sections. Simulated annealing (SA) and tabu search (TS), which are categorized as single‐point‐search heuristics, are applied to the multiobjective optimization problem. It is shown in the numerical examples that the frames that collapse with uniform interstorey drift ratios against various levels of ground motions can be obtained as a set of Pareto optimal solutions. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Assessment of radionuclide transport uncertainty in the unsaturated zone of Yucca Mountain     

Ming Ye  Feng Pan  Yu-Shu Wu  Bill X. Hu  Craig Shirley  Zhongbo Yu 《Advances in water resources》2007

The present study assesses the uncertainty of flow and radionuclide transport in the unsaturated zone at Yucca Mountain using a Monte Carlo method. Matrix permeability, porosity, and sorption coefficient are considered random. Different from previous studies that assume distributions of the parameters, the distributions are determined in this study by applying comprehensive transformations and rigorous statistics to on-site measurements of the parameters. The distribution of permeability is further adjusted based on model calibration results. Correlation between matrix permeability and porosity is incorporated using the Latin Hypercube Sampling method. After conducting 200 Monte Carlo simulations of three-dimensional unsaturated flow and radionuclide transport for conservative and reactive tracers, the mean, variances, and 5th, 50th, and 95th percentiles for quantities of interest (e.g., matrix liquid saturation and water potential) are evaluated. The mean and 50th percentile are used as the mean predictions, and their associated predictive uncertainties are measured by the variances and the 5th and 95th percentiles (also known as uncertainty bounds). The mean predictions of matrix liquid saturation and water potential are in reasonable agreement with corresponding measurements. The uncertainty bounds include a large portion of the measurements, suggesting that the data variability can be partially explained by parameter uncertainty. The study illustrates propagation of predictive uncertainty of percolation flux, increasing downward from repository horizon to water table. Statistics from the breakthrough curves indicate that transport of the reactive tracer is delayed significantly by the sorption process, and prediction on the reactive tracer is of greater uncertainty than on the conservative tracer because randomness in the sorption coefficient increases the prediction uncertainty. Uncertainty in radionuclide transport is related to uncertainty in the percolation flux, suggesting that reducing the former entails reduction in the latter.  相似文献