黄河上游的阶地与水系变迁   总被引：23，自引：3，他引：23  

杨达源  王云飞 《地理科学》1996,16(2):137-143

黄河上游于贵德盆地和共和盆地中有７级阶地，再往上游方向存在阶地级数递减的趋势。共和盆地中还有３级古黄河阶地，黄河上游水系是通过一级级河流袭夺相继贯通的，共和盆地与贵德盆地间的黄河古道始于中更新世末期，龙羊峡河段始于６０ｋａ Ｂ．Ｐ．前后，玛多与唐乃亥 间的峡谷河段是２０ｋａ Ｂ．Ｐ．才贯通的。  相似文献   

发展“三高”果业需重视大生态系统的耗散协调性──剖析龙泉花果山的大生态环境     

刘玲  吴柏清 《四川地质学报》1995,(2)

发展高产优质高效果业，常会涉及到大生态系统的各类环境因子群。龙泉花果山的大生态系统主要是以风化岩体→紫色土容库→蜜桃等构成的向量大系统的综合反映，并呈现非均衡耗散结构的复杂协调性，这些因素直接制约“三高”果业的发展。  相似文献   

BED FORMS AND RESISTANCE PROPERTIES OF LIGHT-WEIGHT BED MATERIAL     

WANG Guixian  WANG Xingkui  GUO Jiachao Professor  Sediment Research Laboratory  Dept. of Hydraulic Engineering  Tsinghua University  Beijing  China. Associate Professor  Dept. of Hydraulic Engineering  Tsinghua University. Assistant  Dept. of Hydraulic Engineering  Tsinghua University. 《国际泥沙研究》1993,(3)

I. INTRODUCTIONResistance to flow in alluvial streams is one of the crucial problems in fluvial hydraulics. Despite that large amount of studies have been conducted for centuries, no perfectmethod describing and calculating the resistance to flow in alluvial streams is availablehll now. Investigation on bed forms and resistance properties of light--weight bed materials is even more scarce. USWES (1936) has conducted systematic experiments onlight--weight materials in a flume & m long an…  相似文献   

滇黔桂卡林型金矿区水系沉积物和岩石金含量与时空分布     

赵东杰  王学求 《地球学报》2020,41(3):407-419

为研究滇黔桂卡林型金矿区水系沉积物和岩石中金的地球化学时空分布及其与金矿规模的对应关系,系统收集了该区1:20万区域化探全国扫面计划水系沉积物和全国地球化学基准计划岩石金的地球化学数据,绘制了水系沉积物和岩石金的地球化学分布图。滇黔桂卡林型金矿区以水系沉积物金地球化学异常面积大于1000 km^2为准,共圈定5处金的地球化学省,这些金的地球化学省同时也是矿床大规模产出的部位。区内右江盆地水系沉积物金背景值(1.94×10^–9)高于扬子克拉通(1.68×10^9),其内以泥岩、页岩、砂岩、灰岩为代表的容矿岩石金背景值(0.51×10^–9)也高于扬子克拉通(0.39×10^–9)。研究区不同构造单元及沉积相中水系沉积物金背景值受岩石金背景值的制约。金的地球化学省是地壳演化过程中不均匀分布的高金背景岩石、金矿化作用及金矿床次生风化作用相互叠加的结果。该研究有助于有效判断异常成因、识别成矿作用存在,对研究金的区域成矿规律和聚焦找矿靶区具有重要意义。  相似文献   

基于ZABBIX的新一代天气雷达ROSE系统监控平台     

王宝云  卢兴来  黄晓龙  陈昊 《气象科技》2021,49(5):730-737

本文通过Zabbix的部署,实现了对新一代天气雷达ROSE系统的台站级监控。整个监控架构分为省级、ROSE平台、本局服务器3层,通过Zabbix模板(Templates)添加的形式可以方便地完成主机性能、网络连接、服务运行状况等监控项目,而通过构造轮询函数监控项和关联触发器函数可以实现流传输的监控和报警;整个监控平台有着功能丰富的前端界面,直观展示ROSE系统运行状况。系统测试表明,Zabbix邮件报警模块功能正常,试运行期间监控平台运行稳定,ROSE系统运行状态评估和实际相符,具备应用推广潜力。  相似文献   

CC天气雷达数据流传输业务台站级监控报警系统的设计与实现     

甄廷忠  唐学军  张琪  方夏馨 《气象科技》2020,48(3):368-373

利用UDP组播通信、进程监控、文件监控、网络监控等技术,研发了CC天气雷达数据流传输业务台站级监控报警系统,较早、较好地实现了雷达扫描状态、数据流上行传输、标准格式基数据本地存储、基数据补传、软件运行和网络运行状态的实时监控和短信报警。实践表明,软件运行较稳定,能对数据流传输业务进行有效监控,短信报警准确及时,报警阈值从6min缩短到40s,提升了故障的发现和处理效率,提高了天气雷达业务可用性和数据传输质量,减轻了雷达台站业务人员的值守压力。  相似文献   

Sea surface height and transport stream function of the South China Sea from a variable-grid global ocean circulation model   总被引：8，自引：0，他引：8  

魏泽勋  方国洪  崔秉昊  方越  何宜军 《中国科学D辑(英文版)》2003,46(2):139-148

The study on the South China Sea (SCS) circulation has a history of more than 40 years. Nevertheless, the SCS circulation is not fully understood compared with the Bohai Sea, Yellow Sea and East China Sea (ECS). Many numerical studies on the SCS circulati…  相似文献   

台风“榴莲”暴雨的湿位涡诊断分析     

农孟松  曾小团 《气象研究与应用》2002,23(1):13-14

分析 2 0 0 1年 7月 2 - 3日台风“榴莲”暴雨过程中湿位涡及其各分量的变化 ,发现对流层低层 85 0 h Pa湿位涡的负值中心、 70 0 h Pa湿位涡的正值区与强降水中心相对应 ;急流与层结稳定度的变化 ,影响着湿位涡的变化  相似文献   

The effects of rock uplift and rock resistance on river morphology in a subduction zone forearc,Oregon, USA     

Sam VanLaningham  Andrew Meigs  Chris Goldfinger 《地球表面变化过程与地形》2006,31(10):1257-1279

Relationships between riverbed morphology, concavity, rock type and rock uplift rate are examined to independently unravel the contribution of along-strike variations in lithology and rates of vertical deformation to the topographic relief of the Oregon coastal mountains. Lithologic control on river profile form is reflected by convexities and knickpoints in a number of longitudinal profiles and by general trends of concavity as a function of lithology. Volcanic and sedimentary rocks are the principal rock types underlying the northern Oregon Coast Ranges (between 46°30′ and 45°N) where mixed bedrock–alluvial channels dominate. Average concavity, θ, is 0·57 in this region. In the alluviated central Oregon Coast Ranges (between 45° and 44°N) values of concavity are, on average, the highest (θ = 0·82). South of 44°N, however, bedrock channels are common and θ = 0·73. Mixed bedrock–alluvial channels characterize rivers in the Klamath Mountains (from 43°N south; θ = 0·64). Rock uplift rates of ≥0·5 mm a⁻¹, mixed bedrock–alluvial channels, and concavities of 0·53–0·70 occur within the northernmost Coast Ranges and Klamath Mountains. For rivers flowing over volcanic rocks θ = 0·53, and θ = 0·72 for reaches crossing sedimentary rocks. Whereas channel type and concavity generally co-vary with lithology along much of the range, rivers between 44·5° and 43°N do not follow these trends. Concavities are generally greater than 0·70, alluvial channels are common, and river profiles lack knickpoints between 44·5° and 44°N, despite the fact that lithology is arguably invariant. Moreover, rock uplift rates in this region vary from low, ≤0·5 mm a⁻¹, to subsidence (<0 mm a⁻¹). These observations are consistent with models of transient river response to a decrease in uplift rate. Conversely, the rivers between 44° and 43°N have similar concavities and flow on the same mapped bedrock unit as the central region, but have bedrock channels and irregular longitudinal profiles, suggesting the river profiles reflect a transient response to an increase in uplift rate. If changes in rock uplift rate explain the differences in river profile form and morphology, it is unlikely that rock uplift and erosion are in steady state in the Oregon coastal mountains. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

入湖河道生态修复工程对水流流速的影响研究   总被引：1，自引：0，他引：1       下载免费PDF全文

田伟君  王超  翟金波  董洁 《水科学进展》2006,17(4):502-506

在河流中开辟生化反应区、直接布设仿生填料净化河流微污染水体可以达到改善入湖水质、减少投资、降低能源消耗的目的。但在河道内直接布设填料势必会对河流的水动力条件及其河流原有的使用功能造成一定的影响。从填料给水流带来的阻力、流速及糙率变化等方面进行河道内直接布设生物填料对河流水动力条件的影响试验分析。结果表明,由于河道流速不大(属于缓流水体),9根/m2的填料布设密度对水流的扰动作用程度不高,填料段的糙率仅为无填料段糙率的1.08倍,不会对河道的泄水能力造成影响。  相似文献