鄱阳湖典型洪泛区地下水数值模拟研究     

曹思佳  李云良  李宁宁  陈静  宋炎炎  赵贵章  李志萍 《湖泊科学》2023,35(1):298-312

受地表河湖系统水情变化干扰,高度动态和异质性的洪泛区地下水文对河湖水资源、水污染以及生态环境功能等方面具有重要影响和贡献。鄱阳湖洪泛区湿地在长江中下游具有重要区位优势和研究特色,但变化环境下其水动力特征和水量交换情况等仍存在许多不确定性。本文以鄱阳湖典型洪泛区为研究区,采用地下水流二维数值模型,开展了洪泛区地表地下水转化作用与水量变化的模拟研究。结果表明,鄱阳湖季节性水位变化很大程度上决定了主湖区与周边地下水之间的动态补排模式,即洪泛区地下水补给湖泊主要发生在枯水和退水时期,而湖泊补给地下水主要发生在涨水和高洪水位时期。一般情况下,整个洪泛区地下水位与湖水位的年内变化态势基本一致,主湖区附近的地下水位年内变幅较大,而大部分洪泛区的地下水位变幅相对较小。北部地下水流速明显大于南部,主湖区附近地下水流速明显大于洪泛区,地下水流速基本小于1～2 m/d。水均衡分析发现,洪泛区地下水系统以接受降雨输入（52%）和主湖区补给（39%）为主,以地下水蒸发输出（72%）和向湖排泄（24%）为主,但补给主要发生在春、夏季,而排泄则发生在秋、冬季。地形地貌对洪泛区地下水位分布以及流速场演化具有主控作用,...  相似文献   

水动力条件下底泥中氮磷释放通量   总被引：28，自引：4，他引：24  

李一平  逄勇  吕俊  张刚  丁玲  彭进平  王超  范丽丽 《湖泊科学》2004,16(4):318-324

在环形水槽内模拟了水动力条件下底泥的起动规律,分析了底泥运动的不同状态。该环形水槽内水体流速基本均匀,水槽转速与槽内水体流速能够精确的相互转换,实验中通过改变水槽转速模拟了不同扰动强度下底泥悬浮和释放的规律．以太湖底泥为例,通过上覆水中TN、TP浓度的变化,建立了底泥中TN、TP的释放通量(y)与水流(x)的关系,其表达式为TN：y=137．88e^0.06x(R^2=0．94);TP：y=36．78e^0.56x(R^2=0．97);并将该实验结果应用在太湖的水量水质模型中,取得了比较满意的效果．  相似文献   

Use of the recession characteristics of snowmelt hydrographs in the assessment of snow water storage in a basin     

Pratap Singh  H. Huebl  H. W. Weinmeister 《水文研究》2000,14(1):91-101

For a better management of water resources, the information on water stored in a basin in the form of snow is of immense use. Changes in the snow water storage with time influence the recession characteristics of the hydrographs. Recession is found to be slower in a basin when it contains higher snow water storage and becomes faster as the volume of stored water reduces. In other words, the recession coefficient is not constant throughout the melt season, it changes with time. In the present study, the possibility of assessing snow water storage at any time during the melt season using recession coefficients is examined. The hydrograph analyses have been made for the Glatzbach watershed in the Hohe Tauern region of the Austrian Alps. For this purpose, a relationship between snow water storage and the recession coefficients is developed. This study suggests a simple and useful approach to assess the snow water storage in a basin at any time during the snowmelt season. The information on the snow water storage of a basin can be obtained using a readily derived single parameter, the recession coefficient. The results are based on limited data, but they are sufficient to illustrate how the changes in snow water storage control the recession characteristics of the hydrographs. These investigations set the pace for further research in this area. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

A generalized seasonal model for flow duration curve     

H. Kerem Cigizoglu  Mehmetcik Bayazit 《水文研究》2000,14(6):1053-1067

In this study a new method is developed to determine a flow duration curve (FDC) for a process in which stream flow is defined as a product of two variables, representing the periodic and the stochastic components, respectively. The cumulative frequency distribution is obtained via integration procedures and also given as an algorithm for discrete variables. Hence the exceedance probability for any given flow value can be calculated. The method is applied to daily flow data from many sites and it is found that the FDCs based on this method compare well with the observed FDC. Furthermore the FDCs developed in this method compare well with other methods in the recent literature. It was found that non‐dimensional flow duration curves in Turkey can be characterized by three, or sometimes just two, parameters. Values of these parameters have been estimated at many sites enabling a FDC to be constructed at neighbouring sites for which only the drainage basin area is known. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

利用水平导数与垂向导数标准偏差的相关系数法识别磁源边界     

郭灿文 《地质与勘探》2020,56(2):418-426

基于导数换算的边界检测技术在位场数据处理与解释中具有重要应用,但是高阶导数算法极易受到干扰噪声的影响,稳定性较差。鉴于此,本文提出利用水平导数与垂向导数标准偏差的相关系数进行边界检测,该方法是基于水平导数与垂向导数的标准偏差在地质体边界位置处呈现负相关性实现的。理论模型试验表明:该方法不仅可以识别出不同深度的异常体的边界位置,而且受噪声影响较小,计算稳定性更强。将本文方法应用于海拉尔盆地实测航磁数据,检测结果与实际资料有着较好的对应关系。  相似文献   

基于散射分量系数的极化SAR数据分类     

杨然  李坤  秦前清 《测绘信息与工程》2010,35(3):23-25

分析了传统的基于散射功率大小的极化SAR数据分类算法,提出了一种基于散射分量系数的改进算法,实现了全极化SAR数据的有效性分类。  相似文献   

THE IMPACT OF PRECEDING ATMOSPHERIC CIRCULATION AND SST VARIATION ON FLOOD SEASON RAINFALL IN YUNNAN   总被引：1，自引：1，他引：0  

严华生  鲁亚斌  程建刚  段鹤  杨素雨 《热带气象学报(英文版)》2005,11(2):121-130

Spatial and temporal distribution characteristics and scale range of two significant areas were obtained by analyzing the relationship among summer rainfall in Yunnan province, height field and SST field (40°S – 40°N, 30 °E – 70°W) across the North Hemisphere at 200 hPa, 500 hPa and 850 hPa for Jan. to May and correlation, and field wave structure. Remote key regions among summer rainfall in Yunnan province, height field and SST field (40°S – 40°N, 30°E – 70°W) across the North Hemisphere at 200 hPa, 500 hPa and 850 hPa were studied through further analyzing of the circulation system and its climate / weather significance. The result shows that the forecast has dependable physical basis when height and SST fields were viewed as predictors and physical models of impacts on rainy season precipitation in Yunnan are preliminarily concluded.  相似文献   

LARGE AMPLITUDE LIQUID SLOSHING IN SEISMICALLY EXCITED TANKS     

W. CHEN  M. A. HAROUN  F. LIU 《地震工程与结构动力学》1996,25(7):653-669

An innovative method of analysis was developed to simulate the non-linear seismic finite-amplitude liquid sloshing in two-dimensional containers. In view of the irregular and time-varying liquid surface, the method employed a curvilinear mesh system to transform the non-linear sloshing problem from the physical domain with an irregular free-surface boundary into a computational domain in which rectangular grids can be analysed by the finite difference method. Non-linearities associated with both the unknown location of the free surface and the high-order differential terms were considered. The Crank–Nicolson time marching scheme was employed and the resulting finite difference algorithm is unconditionally stable and very lightly damped with respect to the temporal co-ordinate. In order to minimize numerical instability caused by the computational dispersion in spatially discretized surface wave, a second-order dissipation term was added to the system to filter out the spurious high-frequency waves. Sloshing effects and structural response were measured in terms of sloshing amplitude, base shear and overturning moment generated by the hydrodynamic pressure of the liquid exerted on the container walls. Simulation results of liquid sloshing induced by earthquake and harmonic base excitations were compared with those of the linear wave theory and the limitations of the latter in assessing the response of seismically excited liquids were addressed.  相似文献   

确定卫星重力场中的海潮负荷影响问题     

孙和平  周江存  彭碧波 《地球科学进展》2006,21(5):482-486

概要综述了确定卫星重力场恢复中的海洋负荷潮汐改正理论和精度估算问题。利用TPXO6海潮模型计算了海潮对卫星重力恢复的影响,与GRACE观测误差实施了对比。结果说明海潮M2波对卫星重力场恢复的影响最大,并主要体现在40阶以下的位系数上。海潮模型误差对低阶卫星重力场恢复的影响也是比较明显的。相关结果可有效降低GRACE恢复的低价重力场位系数的潮汐成分,为我国相应的学科研究提供有效参考。  相似文献   

泥岩裂缝性储层地震勘探方法初探   总被引：7，自引：5，他引：2       下载免费PDF全文

王延光  杜启振 《地球物理学进展》2006,21(2):494-501

针对胜利油田罗家地区以构造裂缝为主、与断层关系密切的特点,本文采用地震资料相干分析和方差分析技术,力求精细而准确地确定该区目的层的断裂系统;提出了地震吸收系数分析技术,期望为确定目的层段的裂缝发育分布提供重要的证据;利用全方位地震信息进行AVA、VVA方法的研究,可望定量地得到目的层段的裂缝方位和密度分布情况;针对AVA和VVA技术的不足,采用了不同方位角阻抗的变化来检测裂缝发育情况的IPVA方法.实例分析表明,该套泥岩裂缝储层勘探方法取得了良好的效果,在泥岩裂缝油气藏定量检测方面获得了重要进展.  相似文献