Development of a continuous soil moisture accounting procedure for curve number methodology and its behaviour with different evapotranspiration methods

The curve number (CN) method is widely used for rainfall–runoff modelling in continuous hydrologic simulation models. A sound continuous soil moisture accounting procedure is necessary for models using the CN method. For shallow soils and soils with low storage, the existing methods have limitations in their ability to reproduce the observed runoff. Therefore, a simple one‐parameter model based on the Soil Conservation Society CN procedure is developed for use in continuous hydrologic simulation. The sensitivity of the model parameter to runoff predictions was also analysed. In addition, the behaviour of the procedure developed and the existing continuous soil moisture accounting procedure used in hydrologic models, in combination with Penman–Monteith and Hargreaves evapotranspiration (ET) methods was also analysed. The new CN methodology, its behaviour and the sensitivity of the depletion coefficient (model parameter) were tested in four United States Geological Survey defined eight‐digit watersheds in different water resources regions of the USA using the SWAT model. In addition to easy parameterization for calibration, the one‐parameter model developed performed adequately in predicting runoff. When tested for shallow soils, the parameter is found to be very sensitive to surface runoff and subsurface flow and less sensitive to ET. Copyright © 2007 John Wiley & Sons, Ltd.     

Lateral flow thresholds for aspen forested hillslopes on the Western Boreal Plain,Alberta, Canada

To predict the long‐term sustainability of water resources on the Boreal Plain region of northern Alberta, it is critical to understand when hillslopes generate runoff and connect with surface waters. The sub‐humid climate (P ≤ ET) and deep glacial sediments of this region result in large available soil storage capacity relative to moisture surpluses or deficits, leading to threshold‐dependent rainfall‐runoff relationships. Rainfall simulation experiments were conducted using large magnitude and high intensity applications to examine the thresholds in precipitation and soil moisture that are necessary to generate lateral flow from hillslope runoff plots representative of Luvisolic soils and an aspen canopy. Two adjacent plots (areas of 2·95 and 3·4 m²) of contrasting antecedent moisture conditions were examined; one had tree root uptake excluded for two months to increase soil moisture content, while the second plot allowed tree uptake over the growing season resulting in drier soils. Vertical flow as drainage and soil moisture storage dominated the water balances of both plots. Greater lateral flow occurred from the plot with higher antecedent moisture content. Results indicate that a minimum of 15–20 mm of rainfall is required to generate lateral flow, and only after the soils have been wetted to a depth of 0·75 m (C‐horizon). The depth and intensity of rainfall events that generated runoff > 1 mm have return periods of 25 years or greater and, when combined with the need for wet antecendent conditions, indicate that lateral flow generation on these hillslopes will occur infrequently. Copyright © 2008 John Wiley & Sons, Ltd.     

有关矿石构造、结构研究的几个问题

本文论述了加强矿石研究的重要性.并对块状构造、浸染状构造、海绵陨铁构造、乳滴状构造、层纹状构造的分类命名及代晶结构的鉴定特征提出了自己的看法.     

辽宁省凤城市四道门沟铁矿床地质特征及成因分析

辽宁省凤城市四道门沟铁矿床位于辽东铁、硼成矿带内。以下元古界辽河群变质岩系最为发育,褶皱构造是直接控制本区变质层控铁硼矿的重要控矿条件,其控制着矿体的产出空间位置,并控制着区内铁矿体的展布特征。该区的铁矿属于火山沉积变质-超变质热液迭生层控矿床,矿石自然类型为磁铁矿-透闪石型,局部有磁铁矿-蛇纹石型和磁铁矿-硼镁铁矿型。     

Google地图应用之广东省地区JOPENS地震速报系统

利用Google公司提供的电子地图服务,以B/S结构(即浏览器和服务器结构)作为系统设计架构,监听JOPENS实时系统发送的地震触发消息,访问JOPENS数据库,根据广东省地区的监测要求,制定检索、筛选策略,获取地震详细信息,显示在浏览器网页上.采用Google地图的JOPENS地震速报系统可以使地震信息发布的显示内容...     

山西交城水峪贯区域构造及地貌形成因素分析

交城水峪贯区域地质构造复杂,三大岩类齐全,岩浆岩类发育,岩层露头特征明显,并伴有煤、铁等矿产分布。区内主要发育NNW、NNE、SN向构造体系,从构造、地貌、地层及岩浆岩等因素分析,本区域经历了多次地质构造运动,对其影响最大的为燕山运动。在早燕山期构造运动中近EW向的主应力作用下形成了本区域古洞道向斜、鲁沿向斜、山前大断裂等构造及狐偃山六大岩浆岩体,后期受应力转变造成本区域X型剪节理发育及构造扭曲等现象。形成了本区域现代地质构造及地貌轮廓。     

青海省天峻县木里煤田聚乎更矿区构造轮廓和地层格架

木里煤田聚乎更矿区是全球陆上中纬度、高海拔冻土带天然气水合物的发现地,也是当前青藏高原地质研究的热点地区之一。依据近年来的煤炭地质勘查资料,对聚乎更矿区的构造轮廓、含煤地层、沉积相和聚煤作用进行深入分析．认为聚乎更矿区位于祁连坳褶带西段,受大通山北缘和托莱山南缘对冲断裂组的制约,构造线总体方向为北西一南东向,构造轮廓表现为南北2个向斜,其中北向斜的煤炭赋存条件优于南向斜。聚乎更矿区含煤地层为中侏罗统木里组和江仓纽。主要可采煤层赋存于木里组上段,聚煤作用主要发生于木里组沉积期的辫状河淤浅之后发育的泥炭沼泽和湖泊、水下三角洲淤浅而发育的泥炭沼泽。     

Idealisation of soil–structure system to determine inelastic seismic response of mid-rise building frames

In this study, a novel and enhanced soil–structure model is developed adopting the direct analysis method using FLAC 2D software to simulate the complex dynamic soil–structure interaction and treat the behaviour of both soil and structure with equal rigour simultaneously. To have a better judgment on the inelastic structural response, three types of mid-rise moment resisting building frames, including 5, 10, and 15 storey buildings are selected in conjunction with three soil types with the shear wave velocities less than 600 m/s, representing soil classes C_e, D_e and E_e, according to Australian Standards. The above mentioned frames have been analysed under two different boundary conditions: (i) fixed-base (no soil–structure interaction) and (ii) flexible-base (considering soil–structure interaction). The results of the analyses in terms of structural displacements and drifts for the above mentioned boundary conditions have been compared and discussed. It is concluded that considering dynamic soil–structure interaction effects in seismic design of moment resisting building frames resting on soil classes D_e and E_e is essential.     

致密砂岩气藏可动流体赋存特征的微观地质因素: 以苏里格气田东部盒8段储层为例

以苏里格气田东部盒8段典型的致密砂岩气藏为例,运用核磁共振、恒速压汞、铸体薄片、物性、X-衍射等实验资料,探讨了影响可动流体赋存差异的微观地质 因素。结果表明,盒8段储层可动流体饱和度低,T₂谱分布均为左高峰右低峰的双峰态;黏土矿物的充填与孔隙类型是孔隙结构复杂的重要因素,孔隙结构是影响可动流体赋存特征的关键;面孔率、喉道 半径、孔喉半径比是影响可动流体饱和度的主要因素,有效孔隙体积、分选系数对可动流体饱和度影响明显,储层物性、黏土矿物、有效喉道体积、孔隙半径对可动流体饱和度影响较弱。