引滦工程对滦河三角洲的影响   总被引：28，自引：5，他引：28  

钱春林 《地理学报》1994,49(2):158-166

本文根据滦河三角洲地区的野外调查及收集的大量资料，以引滦工程对滦河水文的影响为基础，全面系统地分析、论述了三角洲自然环境的变化：三角洲海岸侵蚀后退，地下水位下降，滦河口盐水入侵，土壤盐渍化，河床冲刷、拓宽，河口淤积，预测了三角洲环境演变的趋势，提出了控制三角洲变化的决策。  相似文献   

Injected radiotracer techniques in hydrology     

S. M. Rao 《Journal of Earth System Science》1984,93(3):319-335

Radioactive tracers which have several advantages over conventional tracers made significant contributions to the development of the injected tracer method in hydrology. A review of the nuclear and the physico-chemical characteristics of the possible radiotracer compounds leads us to conclude that the most effective groundwater tracers are tritiated water (HTO),⁸²Br⁻ and⁵⁸Co or⁶⁰Co as a hexacyanocobaltate complex. A discussion of the various case studies in India and abroad covering the three groups of applications mentioned helps us to conclude that well established radiotracer methods with associated interpretational techniques are available for many short range studies in surface and subsurface hydrology.  相似文献   

磁纬20°以下地区哨声多台宽带定向观测及其初步结果          下载免费PDF全文

徐继生  田茂  马淑英  唐存琛  保宗悌 《地球物理学报》1989,(2)

武汉大学哨声组与日本名古屋大学空电研究所合作于1988年1月在我国南方进行了哨声多台宽带定向测量。利用近两年研制的宽带数字化频率追踪定向分析系统,首次获得了磁纬20°以下地区哨声波出口区与偏振状态的实验结果。初步分析发现,在湛江附近(磁纬约10°N)存在一个比较稳定的哨声路径出口区,三台同时接收到的哨声大多从这同一出口区透射出来;有时存在两个出口区,一个仍位于湛江附近,另一个位于桂林和武昌之间;沿两条不同路径传播的同源哨声具有几乎相同的色散。本文所做的非导管射线追踪计算能比较满意地解释定向实验结果。另外,此次观测中还发现一些新的有意义的现象,如记录到近百例两跳、三跳及五跳回波等,这在低纬地区是非常少见的。  相似文献   

Non-Linear, Microscale Modelling of the Flow Over Askervein Hill     

O. Undheim  H. I. Andersson  E. Berge 《Boundary-Layer Meteorology》2006,120(3):477-495

The flow solver “3DWind” is used to explore new aspects of the Askervein hill flow case. Previous work has investigated sensitivities to the grid, the inflow boundary profile, the roughness and the turbulence model. Several different linear and non-linear numerical models have also been validated by means of the Askervein hill case. This analysis focuses on the flow sensitivity to the grid spacing, the incident wind direction and the vertical resolution of topographic data. The horizontal resolution is found to be fine enough to cause only minor differences compared to a grid where every second node is removed. The vertical resolution dependence is mainly attributed to the wall functions. Simulations are performed for wind directions 200°, 205°, 210° and 215° at the reference station. The smallest directional biases compared to experimental values along a line through the hilltop are found for the directions 200° and 205°. There are larger wind direction changes along this line through the hilltop in the 200° case than in the 215° case. Still the simulation results give less veering than found in the experimental results, and this is maybe caused by a slightly stable atmosphere. The sensitivity to the vertical resolution of the topographical data is found to be particularly high close to the ground at the top of the hill; this is where the speed-up is most important. Differences decrease with the height from the ground. At higher levels the speed-ups are smaller and caused by terrain formations with larger scales.  相似文献   

Mitigation of seismic and meteorological hazards to marine oil terminals and other pier and wharf structures in California     

M. L. Eskijian 《Natural Hazards》2006,39(2):343-351

For the past 12 years, the California State Lands Commission has been involved in the operational monitoring, structural inspection and requalification of 45 marine oil terminals along California’s coast, which have an average age of about 50 years and plans to keep these structures in service for another 20–40 years. Having seen the port and harbor damage from the 1995 Kobe and 1999 Izmit earthquakes, the potential for a major disruption in petroleum product production is real. Losing the daily gasoline production for a period of weeks or months as a result of a moderate earthquake or tsunami could significantly affect the economic well being of California and much of the western United States. In addition, a major oil spill resulting from such an event could cause the closure of a major port for days or even weeks. Such a closure would further affect the economy of California and the United States. Most of these facilities were designed to primitive seismic standards and for vessels much smaller than those currently moored. Many of these structures have never had a comprehensive underwater inspection. Wind and current forces on large tank ships can cause mooring lines to break or cause serious structural damage to supporting structures. In California, non-regulatory progress has been made in the following areas: (i) underwater and above water inspections or audits; (ii) mooring analyses and structural/environmental monitoring in high velocity current areas; (iii) seismic analyses and structural rehabilitation with updated seismic hazard data; and (iv) accelerometers on marine structures. In addition, standards have been developed and are proposed to be regulatory by early 2004. The new standards include most of the items listed above, but also extend into many other areas. Along with the proposed regulations come many issues that raise economic and political questions. These issues are not unique to marine oil terminals and are applicable to other pier and wharf structures in harbors.  相似文献   

Impact of Climate Change on the Regional Hydrology – Scenario-Based Modelling Studies in the German Rhine Catchment     

Lucas Menzel  Annegret H. Thieken  Daniel Schwandt  Gerd Bürger 《Natural Hazards》2006,38(1-2):45-61

The aim of the study is an impact analysis of global climate change on regional hydrology with special emphasis on discharge conditions and floods. The investigations are focussed on the major part of the German Rhine catchment with a drainage area of approx. 110,000 km². This area is subdivided into 23 subcatchments. In a first step, the hydrological model HBV-D serves to simulate runoff conditions under present climate for the individual subbasins. Simulated, large scale atmospheric fields, provided by two different Global Circulation Models (GCMs) and driven by the emission scenario IS95a (“business as usual”) are then used as input to the method of expanded downscaling (EDS). EDS delivers local time series of scenario climate as input to HBV-D. In a final step, the investigations are focussed on the assessment of possible future runoff conditions under the impact of climate change. The study indicates a potential increase in precipitation, mean runoff and flood discharge for small return intervals. However, the uncertainty range that originates from the application of the whole model chain and two different GCMs is high. This leads to high cumulative uncertainties, which do not allow conclusions to be drawn on the development of future extreme floods.  相似文献   

官地银金矿中锰的化学物相分析     

盛民陈会军  范胜芹 《岩矿测试》2006,25(4):389-390

根据官地银金矿中锰矿物的共生组合情况，引用Al（NO3）3溶液作碳酸锰矿物的选择性溶剂，H2SO4-KF-HF混合溶液作水锰矿、褐锰矿的选择性溶剂，于滤渣中测定软锰矿（包括少量硅酸锰矿物）。实验表明，所引方法适用于官地银金矿区锰矿物的相态分离，所得结果与外检结果一致，满足了矿床划带的实际需要。  相似文献   

R型聚类分析在成矿阶段划分中的应用-以桦甸大庙子-菜抢子金矿区为例   总被引：2，自引：0，他引：2  

张彦艳  王建新  赵志  尹占军  谢海东  臧兴运 《世界地质》2006,25(1):29-33,38

大庙子—菜抢子金矿区主要矿石类型有含金黄铁矿型和含金多金属型,对两类矿石研究表明金赋存于黄铁矿和交代、穿切黄铁矿的黄铜矿中,主要与黄铁矿有关。采用相关系数法、距离系数法及离差平方和法对38件矿石样品中的Au、Ag、Cu、Pb、Zn、Co、Ni、Bi元素进行R型聚类分群,结果为Au Bi、Ag Zn Cu Co Pb Ni二群。本矿区中金主要形成于金-黄铁矿阶段,少量形成于金-多金属阶段。  相似文献   

我国水文资料整编和数据库技术发展综述     

章树安  吴礼福  林伟 《水文》2006,26(3):48-52

水文是水利和国民经济建设与发展重要的基础工作。经过整编的水文资料是国家重要的基础信息资源之一, 它被广泛应用于防汛抗旱、水工程规划设计、水资源管理与开发利用、水环境保护、水科学研究及其他国民经济建设。长期以来,水文资料为我国水利和国民经济建设与发展提供了科学决策依据。随着经济社会发展和人民生活水平不断提高,对控制水旱灾害、水环境监测与保护、水土保持与生态、水资源管理等方面要求越来越高,对水文资料分析处理、存储、应用服务要求也相应提高。本文主要从技术角度,对我国水文资料整编主要技术方法和水文年鉴发展进行了总结与分析;对水文数据库有关技术标准制定、水文数据库建设成就进行回顾;同时结合水文信息共享和应用服务需求,对相关技术发展进行了展望。  相似文献   

地质环境质量评价的态势分析法     

刘建东  杨泉宁  薛怀友  张发明 《江苏地质》2006,30(1):17-20

探讨了将SWOT态势分析法应用于地质环境质量评价中的具体步骤。通过长江江苏段过江隧道工程的地质环境质量等级评价的实例,从地质体本身的优势、劣势,外部条件的有利(机会)、不利(威胁)等4个方面对评价对象进行全面、系统、准确的研究,最后得出地质环境质量的评价等级。  相似文献