30-60-day Oscillations of Convection and Circulation Associated with the Thermal State of the Western Pacific Warm Pool during Boreal Summer   总被引：4，自引：0，他引：4  

REN Baohu  HUANG Ronghui 《大气科学进展》2003,20(5):781-793

This study focuses on the characteristics of the 30-60-day oscillation (MJO) associated with the interannual variability of the thermal state in the western Pacific warm pool. The composite results show that the amplitude of MJO convection over the tropical western Pacific tends to intensify (reduce) in the WARM (COLD) case. The negative correlations between MJO convection in the WARM and inthe COLD cases are examined to be significant over most of the Asian-Pacific region. The evolutions of MJO convection and lower circulation, on the one hand, exhibit larger differences between the WARM and COLD cases, but on the other hand, display a unique feature in that a well-developed MJO cyclone (anticyclone) is anchored over the Asian-Western Pacific domain at the peak enhanced (suppressed) MJO convection phase over the western Pacific warm pool, either in the WARM or in the COLD case. This unique feature of MJO shows a Gill-type response of lower circulation to the convection and is inferred to be an inherent appearance of MJO. The context in the paper suggests there may exist interactions between MJO and the interannual variability of the thermal state in the western Pacific warm pool.  相似文献   

川、滇、黔交界地区密西西比河谷型铅锌矿床与美国同类矿床的对比   总被引：42，自引：4，他引：42  

王奖臻  李朝阳  李泽琴  李葆华  刘文周 《矿物岩石地球化学通报》2002,21(2):127-132

我国川、滇、黔交接地区和美国中部地区的密西西比河谷型铅锌矿床的共同特征是：1）含矿岩系都位于一套红色碎屑岩石之上。它们不但为矿床的形成提供了成矿金属，而且由于渗透率较大而为成矿流体的大规模侧向流动提供了通道。2）矿床的形成时间都与造山作用的时间相一致。造山作用所引起的挤压应力，或由于造山带的隆起所引起的盆山间的重力梯度为含矿流体的大规模侧向流动提供了动力，促进了成矿作用的发生。3）矿床的含矿岩系大多含有蒸发岩。蒸发岩的存在为成矿流体的形成提供了矿化剂，或为矿质的沉淀提供了硫。  相似文献   

聚氨酯泡塑对不同价态金吸附性能的研究及应用   总被引：7，自引：0，他引：7  

邹海峰  田丽玉等 《岩矿测试》2001,20(3):187-190

研究了聚氨酯泡沫塑料对不同价态金的吸附行为，选择了泡塑吸附和硫脲解脱以及用原子吸收法测定的最佳条件。方法已应用于黄铁矿和毒砂单矿物中价态金的测定，黄铁矿中各价态金的加和与总金量相符，加标回收实验Au(Ⅲ），Au(Ⅰ),Au(0)的回收率分别为98＝5％，98．8％和104％，为矿样中痕量金的价态分析提供了一个可靠的方法。  相似文献   

Decolonisation without independence     

A.J. Christopher 《GeoJournal》2002,56(3):213-224

The massive decolonisation of the post World War II era resulted in a new political map of the world. The great majority of the new independent states were essentially coincident with the former administrative colonies. However, in a quarter of cases the ending of colonial status did not result in the emergence of a sovereign state. The colonial powers sought to reduce the number of small and potentially weak states by various mechanisms. Thus colonial mergers took place between administrative units within the same empire, and only occasionally between units in different empires. Some dependencies were absorbed by more powerful neighbours and others incorporated into the political structure of the metropolitan power. Prior to 1960, in terms of population and size, the colonies which failed to achieve statehood at independence were substantially smaller than those which did. Thereafter there was little to distinguish them. The legacy of the merged colonies has ranged from successful secessionist movements to integrated states. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

东北三省城市拟态与现实人居环境时空耦合协调特征与机制   总被引：4，自引：1，他引：3  

田深圳  李雪铭  杨俊  张威  郭建科 《地理学报》2021,76(4):781-798

单一形态的现实人居环境研究,不能合理诠释人地关系地域系统下日益变化的人居环境现象。目前,不同形态人居环境相互作用的理论基础、实践探索以及科学决策等问题并不清晰。建构城市拟态与现实人居环境耦合协调的理论框架,运用耦合协调模型、空间趋势分析、地理探测器等实证分析2011—2017年东北三省34个地级市耦合协调的时空规律,并对其影响因子和驱动机制进行探讨。结果表明：① 东北三省城市耦合度总体呈现出上升的态势,具有相对明显的阶段特征;空间上形成双核与单中心并存的格局,并由分散的团状向“T”型团带状空间格局演变;② 协调度总体处于濒临失调状态,协调互动稳步向高级别发展演变,中级协调占据一定地位,高级协调开始出现;协调度的核心极化空间格局特征明显,四大城市主导着东北三省整体的协调互动级别;同时形成省内“极化与均衡并存”、省际“北低南高”、整体“中心—边缘—低洼地”等区域差异的空间格局;协调度整体呈现出东西方向的“中间凸起、两端略低的倒‘U’型”与南北方向上的“南高北低”的空间趋势特征;③ 拟态与现实人居环境耦合协调发展是多种因子综合作用的结果,其中社会经济发展是主导性驱动,“人”是本底性驱动,娱乐系统是新兴性驱动,社交系统是重要的媒介性驱动。  相似文献   

Correlation between successive wave heights and periods in mixed sea states     

Germn R. Rodríguez  C. Guedes Soares 《Ocean Engineering》2001,28(8)

The degree of dependence between successive wave heights and periods is examined for sea states resulting from the combination of a remotely generated wave field and a locally generated wave system, based on simulated wave records. The sea states analysed represent situations that are swell dominated, wind–sea dominated or they have equivalent energy in the wind–sea and swell components. Results of the analysis of the simulated data have been compared with those expected from the theories for the joint distributions of consecutive wave heights and periods and with the results from a Pierson–Moskowitz target spectrum.  相似文献   

广西钦州内湾贝类养殖海区三氮的含量和百分组成   总被引：4，自引：1，他引：4  

韦蔓新  赖廷和  何本茂 《台湾海峡》2001,20(4):441-446

本文根据1998年10月和1999年5月的调查资料，报道了钦州内湾帆类养殖海区三态氮的含量和百分组成。结果表明：NO3－N是本水域无机氮的主要存在形式；三态氮之间的相互转化以春季进行得比较充分，95．70％均已转化为NO3－N，基本达到了热力学平衡状态，NO3－N与NH4－N和NO2－N之间均具有显著的正相关关系；秋季，只有79．87％的无机氮转化为NO3－N，没有达到热力学平衡状态，但NO3－N与NH4－N却具有高度显著的负相关关系，与NO2－N的相关性较差。  相似文献   

海南岛新海湾海滩地貌状态与海岸泥沙纵向运动特征   总被引：5，自引：0，他引：5       下载免费PDF全文

陈子燊 《海洋与湖沼》1993,24(5):467-476

根据１９９０年现场调查及前期观察资料，论述了海南岛新海弧形海湾不同岸段由主要动力驱动过程和海滩地貌结构组成的４种海滩地貌状态，为Ⅰ．隐蔽段消散类型，Ⅱ．脊－沟体系与低潮台地类型，Ⅲ．韵律海滩与砂坝类型，Ⅳ．开敞段消散类型。应用泥沙粒级参数概率模型分析近岸泥沙纵向运动趋势，结果表明，常波况下，沿岸泥沙存在双向运动，湾顶海滩为汇集地带，泥沙纵向运动主趋势为西南向；高能条件下，海岸北段可出现北向泥沙运动  相似文献   

Reforming management of commercial fisheries in a small island territory     

Michael Harte  John Barton 《Marine Policy》2007

The Falkland Islands has successfully met many challenges in the management and development of its fisheries resources over the last 20 years. To meet a new set of challenges the current licensing system based on the allocation of non-transferable, variable duration licences to individual vessels is being replaced by a system of long-term individual transferable rights owned by Falkland Islanders. The anticipated gains are enhanced economic performance of the sector because fishing businesses have increased security and flexibility, rapid diversification from harvesting into value-added activities and increased international competitiveness as poorly performing companies sell rights to well performing companies. Implementing a rights-based regime in a small coastal state is challenging. Thin markets for rights, a desire to maintain local control of fishing rights, and a dependence on foreign direct investment in the fisheries sector are key considerations in the design of an effective and efficient management regime. Starting operation in 2006/07, the new rights-based management system provides a model for small coastal states or small industrial fisheries that previously had considered rights-based systems too complex to implement and administer, despite the inherent advantages of rights-based management.  相似文献   

Groundwater arsenic contamination in Manipur,one of the seven North-Eastern Hill states of India: a future danger   总被引：1，自引：0，他引：1  

Dipankar Chakraborti  E. Jayantakumar Singh  Bhaskar Das  Babar Ali Shah  M. Amir Hossain  Bishwajit Nayak  Sad Ahamed  N. Rajmuhon Singh 《Environmental Geology》2008,56(2):381-390

Manipur State, with a population of 2.29 million, is one of the seven North-Eastern Hill states in India, and is severely affected by groundwater arsenic contamination. Manipur has nine districts out of which four are in Manipur Valley where 59% of the people live on 10% of the land. These four districts are all arsenic contaminated. We analysed water samples from 628 tubewells for arsenic out of an expected total 2,014 tubewells in the Manipur Valley. Analyzed samples, 63.3%, contained >10 μg/l of arsenic, 23.2% between 10 and 50 μg/l, and 40% >50 μg/l. The percentages of contaminated wells above 10 and 50 μg/l are higher than in other arsenic affected states and countries of the Ganga–Meghna–Brahmaputra (GMB) Plain. Unlike on the GMB plains, in Manipur there is no systematic relation between arsenic concentration and the depth of tubewells. The source of arsenic in GMB Plain is sediments derived from the Himalaya and surrounding mountains. North-Eastern Hill states were formed at late phase of Himalaya orogeny, and so it will be found in the future that groundwater arsenic contamination in the valleys of other North-Eastern Hill states. Arsenic contaminated aquifers in Manipur Valley are mainly located within the Newer Alluvium. In Manipur, the high rainfall and abundant surface water resources can be exploited to avoid repeating the mass arsenic poisoning that has occurred on the GMB plains.  相似文献