Rainfall intensity affects runoff responses in a semi-arid catchment     

Ze Tao  Min Li  Bingcheng Si  Dyan Pratt 《水文研究》2021,35(4):e14100

The source and hydrochemical makeup of a stream reflects the connectivity between rainfall, groundwater, the stream, and is reflected to water quantity and quality of the catchment. However, in a semi-arid, thick, loess covered catchment, temporal variation of stream source and event associated behaviours are lesser known. Thus, the isotopic and chemical hydrographs in a widely distributed, deep loess, semi-arid catchment of the northern Chinese Loess Plateau were characterized to determine the source and hydrochemical behaviours of the stream during intra-rainfall events. Rainfall and streamflow were sampled during six hydrologic events coupled with measurements of stream baseflow and groundwater. The deuterium isotope (²H), major ions (Cl⁻, SO₄²⁻, NO₃⁻, Ca²⁺, K⁺, Mg²⁺, and Na⁺) were evaluated in water samples obtained during rainfall events. Temporal variation of ²H and Cl⁻ measured in the groundwater and stream baseflow prior to rainfall was similar; however, the isotope compositions of the streamflow fluctuated significantly and responded quickly to rainfall events, likely due to an infiltration excess, overland dominated surface runoff during torrential rainfall events. Time source separation using ²H demonstrated greater than 72% on average, the stream composition was event water during torrential rainfall events, with the proportion increasing with rainfall intensity. Solutes concentrations in the stream had loglinear relationships with stream discharge, with an outling anomaly with an example of an intra-rainfall event on Oct. 24, 2015. Stream Cl⁻ behaved nonconservative during rainfall events, temporal variation of Cl⁻ indicated a flush and washout at the onset of small rainfall events, a dilution but still high concentration pattern in high discharge and old water dominated in regression flow period. This study indicates rainfall intensity affects runoff responses in a semi-arid catchment, and the stored water in the thick, loess covered areas was less connected with stream runoff. Solute transport may threaten water quality in the area, requiring further analysis of the performance of the eco-restoration project.  相似文献   

康古尔塔格缝合带的变形机制     

王洋  陈练武 《地球科学与环境学报》1996,(4)

北天山东段康古尔塔格带是晚古生代塔里木板块和准噶尔板块碰撞的结果。它是一条复杂的、强烈的高应变带．并具有独特的变形机制、应变序列以及构造变形。本文运用构造－地层研究方法对该碰撞带的构造特征加以分析和研究。  相似文献   

APPLICATION OF GEOGRAPHICAL PARAMETER DATABASE TO ESTABLISHMENT OF UNIT POPULATION DATABASE   总被引：1，自引：1，他引：0  

DONG Chun  ZHAO Rong  LIU Ji-ping  WANG Gui-xin  WU Xi-zhi 《中国地理科学(英文版)》2003,13(1):34-38

Now GIS is turning into a good tool in handling geographical, economical, and population data, so we can obtain more and more information from these data. On the other hand, in some cases, for a calamity, such as hurricane, earthquake, flood, drought etc., or a decision-making, such as setting up a broadcasting transmitter, building a chemical plant etc., we have to evaluate the total population in the region influenced by a calamity or a project. In this paper, a method is put forward to evaluate the population in such special region. Through exploring the correlation of geographical parameters and the distribution of people in the same region by means of quantitative analysis and qualitative analysis, unit population database (1km× 1km) is established. In this way, estimating the number of people in a special region is capable by adding up the population in every grid involved in this region boundary. The geographical parameters are obtained from topographic database and DEM database on the scale of  相似文献   

浅议地勘单位的物业管理     

柯娜 《南方国土资源》2001,14(4):57-60

文章阐述了地勘单位物业管理社会化的必然性和内函 ,提出发展地勘单位物业管理的基本内容和需要解决的问题 ,最终实现以业养业 ,自我发展。  相似文献   

Numerical estimation of REV and permeability tensor for fractured rock masses by composite element method   总被引：2，自引：0，他引：2  

S.‐H. Chen  X.‐M. Feng  S. Isam 《国际地质力学数值与分析法杂志》2008,32(12):1459-1477

The Monte Carlo method is used to generate parent stochastic discrete fracture network, from which a series of fractured rock samples of different sizes and orientations are extracted. The fracture network combined with a regular grid forms composite element mesh of the fractured rock sample, in which each composite element is composed of sub‐elements incised by fracture segments. The composite element method (CEM) for the seepage is implemented to obtain the nodal hydraulic potential as well as the seepage flow rates through the fractured rock samples. The application of CEM enables a large quantity of stochastic tests for the fractured rock samples because the pre‐process is facilitated greatly. By changing the sizes and orientations of the samples, the analysis of the seepage characteristics is realized to evaluate the variation of the permeability components, the existence of the permeability tensor and the representative element volume. The feasibility and effectiveness are illustrated in a numerical example. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

基于霍顿下渗能力曲线的流量过程线连续分割方法研究   总被引：2，自引：0，他引：2  

林凯荣  郭生练  张文华 《水文》2008,28(1):10-14

在用前期影响雨量代替流域蓄水量的基础上,提出了基于霍顿下渗能力曲线的流量过程线的连续分割方法.选择西峡、猴子岩和东湾三个流域的降雨径流资料,采用该方法对流量过程线进行分割,并与现行的数字滤波法、非线性水库法和Boussinesq方程法相比较.结果表明,该方法具有一定的物理基础、符合产汇流基本规律,而且能够减少涨洪段流量过程线分割的主观性,对于流域时段单位线和降雨径流关系的推求均有重要的意义.  相似文献   

空间刚架结构极限强度分析     

刘修禾 《海洋工程》1997,(3)

本文用理想结构单元法对空间刚架结构进行了极限强度分析，理想结构单元法在于将结构分成最大可能的单元。以简单的形式归并几何非线性与材料非线性。按增量形式加载，直到达到极限强度。本文根据Ｒａｓｈｅｄ理论导出了对称的切向方程组，节省了存贮单元、改善了破坏准则的描述。算例结果与非线性有限单元法结果十分吻合。  相似文献   

Dynamic properties of green water event in the overtopping of extreme waves on a fixed dock     

Nobuhito Mori  Daniel T. Cox 《Ocean Engineering》2003,30(16):2021-2052

A statistical model is developed to predict wave overtopping volume and rate of extreme waves on a fixed deck. The probability density function for the volume and rate of overtopping water are formulated based on the truncated Weibull distribution with the assumption of local sinusoidal profile for small amplitude waves. Sensitivity to the wave nonlinearity parameter and deck clearance is discussed. The statistical model is compared to laboratory data of the instantaneous free surface elevation measured in front of a fixed deck, and overtopping volume and overtopping rate measured at the leading edge of the deck. The statistical theory compared well with the measured exceedance probability seaward of the deck. The model prediction of the exceedance probability of deck overtopping gave qualitatively good agreement for large overtopping values.  相似文献   

钛型吸附剂的表面特性     

谢式南  王俊鹤  周英兰  孙爱平 《中国海洋大学学报(自然科学版)》1990,(3)

用自装的BET容量法装置测定了几种粒状钛型吸附剂的比表面及其孔径分布。测定是在常温减压下进行的。结果表明:钛型吸附剂在加铀海水中的吸铀量与样品的比表面及孔径分布有一定的内在联系。这种表面性质的研究对吸附剂的筛选有重要的指导意义。  相似文献   

A community-wide intercomparison exercise for the determination of dissolved iron in seawater     

Andrew R. Bowie  Eric P. Achterberg  Peter L. Croot  Hein J.W. de Baar  Patrick Laan  James W. Moffett  Simon Ussher  Paul J. Worsfold 《Marine Chemistry》2006

The first large-scale international intercomparison of analytical methods for the determination of dissolved iron in seawater was carried out between October 2000 and December 2002. The exercise was conducted as a rigorously “blind” comparison of 7 analytical techniques by 24 international laboratories. The comparison was based on a large volume (700 L), filtered surface seawater sample collected from the South Atlantic Ocean (the “IRONAGES” sample), which was acidified, mixed and bottled at sea. Two 1-L sample bottles were sent to each participant. Integrity and blindness were achieved by having the experiment designed and carried out by a small team, and overseen by an independent data manager. Storage, homogeneity and time-series stability experiments conducted over 2.5 years showed that inter-bottle variability of the IRONAGES sample was good (< 7%), although there was a decrease in iron concentration in the bottles over time (0.8–0.5 nM) before a stable value was observed. This raises questions over the suitability of sample acidification and storage.  相似文献