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51.
海底观测网络由于其特有的能源供给与信息传输优势,受到了广泛关注与重视。文中简要回顾了国内外海底观测网技术的发展现状,并就海底观测网技术发展趋势进行了探讨。  相似文献   
52.
受人类活动的影响,海洋污染日益严重。我国海岸带、河口和海湾生态系统均受到了不同程度的破坏。海洋生态环境监测传感器的应用可实现实时海洋环境的监测和快速预警,对于预防海洋灾害、调节海洋经济发展与环境之间的矛盾有重要意义。文中归纳了海洋生态环境类传感器所应用的分析检测技术,总结了目前所研发的各类海洋生态环境传感器,预测了传感器的发展趋势,并对我国未来传感器的研究工作提出了建议。  相似文献   
53.
对近年来有关生物质燃烧排放的颗粒物中有机化合物和有机示踪物的研究进展进行了综述,分析了各国学者根据有机示踪物研究城市大气颗粒物中生物质燃烧和其他排放源对空气污染的贡献,对以后的相关研究具有借鉴意义.  相似文献   
54.
In this paper the spatial and temporal responses of the Some?u Mic River (Romania) to natural and anthropogenic controls over the past 150 years are analysed, based on a series of morphometric parameters extracted from five successive sets of topographic maps and one set of orthophotos. Prior to the intensive hydrotechnical interventions of the last four decades, the river was characterized by a complex alternation of different channel types, resulting in a mixture of alluvial and mixed sinuous – meandering – sinuous anabranched – meandering anabranched reaches, each a few hundred metres to a few kilometres long. The main cause for this spatial behaviour was the local geology. Its effects were intensified by a larger scale slope, slightly higher than along a longitudinal profile with normal concavity, as a consequence of the presence of a 400 m elevation knick‐point located in the catchment area. A generalized maintenance of river in the floodplain perimeter during the entire interval of study (centennial scale), with local planform adjustments and lack of median scale avulsion in lateral tilting areas and along the anabranched reaches, channel lengthening and meander development during hydrological stable periods and channel shortening and increasing of natural cutoffs during periods with higher incidence of floods (decadal scale), and the incapacity of local morphologic changes resulted from human interventions to completely counterbalance general trends (decadal scale), supports the idea of decreasing the amplitude and frequency of important floods, after the end of the Little Ice Age. Channel metamorphosis by canalization, diminishing/elimination of overflows and medium‐scale avulsions by changes in flow regimes (dams) and the presence of dykes in the floodplain perimeter, channel narrowing (43%) and incision (at least after 1945) downstream from dams, and probably because of in‐channel gravel mining are the main anthropically induced changes along the Some?u Mic River. Even if human impact is important, both at the drainage basin scale and along the Some?u Mic River, it has only local impacts, subordinated to climate. The low level of human impact on this river could be the consequence of the higher general slope downstream from 400 m elevation knick‐point, which probably forces the positioning of its effects under an important internal threshold of the fluvial system. This boundary condition defines Some?u Mic River as an atypical river. This study supports the idea that climate has a more important role in the post‐Little Ice Age (LIA) rivers' behaviour than currently accepted. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
55.
Historical range of variability (HRV) describes the range of temporal and spatial variations in river variables such as flow regime or channel planform prior to intensive human alteration of the ecosystem. In mountainous river networks, HRV is most usefully applied to spatially differentiated geomorphic process domains with distinctive form and process. Using the Colorado Front Range as an example, three examples of how knowledge of HRV can assist river management and restoration are discussed. The examples involve instream wood load and channel morphology, beaver colonies and valley‐bottom form and process, and flow thresholds in regulated rivers. The question of what a river should look like – that is, what range of process and form the river included prior to intensive human alteration – can be addressed by (i) placing the river within a process domain, (ii) establishing correlations between form parameters that can be remotely sensed and reach‐scale process and form, so that the spatial extent, connectivity, and rarity of process domains within a river network or a region can be quickly assessed, (iii) inferring characteristics of the river prior to intensive alteration by documenting characteristics of the least altered reference rivers and by using proxy indicators of pre‐alteration conditions, and (iv) establishing process thresholds that must be exceeded to maintain form (e.g. flow thresholds to mobilize bed sediment). Once this context has been established, resource managers can better evaluate the options for restoring altered riverine form and function. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
56.
中国大陆中强地震余震序列的研究(王华林,周翠英,1997;刁守中等,2002;蒋海昆等,2006)表明,中强地震序列类型空间分布具有统计意义上较明显的区域性特征.即某些区域中强地震以某种类型的序列活动为主,另一些区域又以另外类型的序列活动为主,固定区域的序列类型保持相对的稳定性.事实上,  相似文献   
57.
The Antarctic and Arctic are sensitive to global climate change; therefore, they are key regions of global climate change research. This paper, the progress in scientific investigations and research regarding the atmosphere in the polar regions over the last 30 years by Chinese scientists is summarized. Primary understanding of the relationship between the polar regions and global change, especially, the variations in time and space in the Antarctic and Arctic regions with respect to climate change is indicated. Operational weather forecasts for investigation of the polar regions have also been established. Moreover, changes in sea ice and their impact on the atmosphere of polar regions have been diagnosed and simulated. Parameterization of the atmospheric boundary layer of different underlying layers and changes in the atmospheric ozone in the polar region has also been experimented. Overall, there has been great progress in studies of the possible impact of changes in the atmospheric environment of polar regions on circulation in East Asia and the climate of China.  相似文献   
58.
本文回顾了中国科学院地理科学与资源研究所建所70年城市地理与城市发展研究的变迁历程,并将其划分为缓慢探索阶段(1949-1980年)、积极参与阶段(1981-1990年)、快速拓展阶段(1991-2000年)和逐步深化阶段(2000年以来)4大阶段,系统总结了城市地理科研工作者在中国设市预测与规划调整、中国城镇体系规划...  相似文献   
59.
近30年中国极地气象科学研究进展   总被引:1,自引:0,他引:1       下载免费PDF全文
南极和北极是地球上的气候敏感地区,也是研究全球变化的关键区域.中国的南极和北极实地科学考察研究,分别始于20世纪80年代和90年代.作为国家行为,到2010年底,已经组织了27次南极考察、4次北极北冰洋考察和7次北极陆地考察;在南北极建立了4个科学考察站、5个(中澳/中美)合作自动气象站;初步形成了以有人考察站、无人自...  相似文献   
60.
中国城市地理学研究进展与展望   总被引:1,自引:0,他引:1  
城市地理学是研究在不同地理环境下,城市形成发展、组合分布和空间结构变化规律的科学,既是人文地理学的重要分支,又是城市科学群的重要组成部分。中国城市化的加速发展为中国城市地理学乃至世界城市地理学的发展提供了直接的营养。回顾过去几年中国城市地理学的发展,归纳起来呈现如下几方面的特点:中国城市地理学研究与国家经济建设的热点总体同步;在城市化、城市群/圈等领域积极参与国家战略和城市建设实践;强调定量和计量手段的科学研究悄然成为潮流;积极开辟和强化中国城市地理学研究的新基地、新力量;以更开放、更创新的视野,积极开创前沿性、战略性的新研究领域;推出年青人等计划初现成效。与国外相比,中国城市地理学在城市化和城市体系研究方面已形成自己的独特理论,并具有高度的实践性,中国城市地理学更好地实现了从知识生产到知识应用、反馈、知识再生产的良性循环。展望城市地理学的学科发展趋势,中国城市地理学在城市化加速的今天,认识城市、改造城市的道路仍任重而道远。为此我们一方面需要面向城市化背景,进行中国城市地理学理论和实践的战略思考,缩短中国城市地理学与主流的城市地理学的距离,通过大人文与大科学交融进行城市地理学方法论的建立和完善、国际视野和地方行动;另一方面需要面向国家“十二五”等近期发展目标和重点,积极的设计和执行中国城市地理学近期行动计划。  相似文献   
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