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Karen Edelvang M.Sc. Michael Larsen M.Sc. assoc. prof. Morten Pejrup Ph.D. 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):116-119
Edelvang, Karen; Larsen, Michael; Pejrup, Morten: Tidal Variation in Field Settling Velocities of Suspended Sediment in a Tidal Channel. Geografisk Tidsskrift 92:116–121. Copenhagen 1992. Particles of silt and clay may form large, low density floes when suspended in salt water. The sediment floes have settling velocities much higher than the single small particles constituting them and therefore, the flocculation process may strongly influence the transport of cohesive sediment in estuarine environments. will be described in this paper, the field settling velocities of suspended sediment were investigated in a large tidal channel with tidal current velocities up to 1.3 m/s and depths of about 10 m. The analyses of suspended sediment were made on both bottom and surface samples. For the bottom samples, equivalent median fall diameters in the range 26–98 μm were measured. For surface samples, the range was 15–40 μm. During most of the tidal period, the occurrence of much larger settling diameters near the bottom was due to the suspension of individual sand and silt particles. For the investigated periods, high-tide was the only possible time to observe flocculation influencing the vertical distribution of finegrained sediment in the water column. 相似文献
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《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(5-8):328-344
Den brem av lavt land langs fastlandet og rundt do større øer, som vi kaller strandflaten, og som vi tror brenningen har laget, blir bred og vid når bølgene arbeider mot bløtt berg som på Jæren. Men ved Bru i Ogna, hvor silurberget møter de hårde labradorbergarter, forsvinner strandflaten og her slutter også Jæren. Ved gården Sæland er Jæren 20 km bred; et par km lenger nord skrumper bredden inn til 14 km. Min kartskisse (1) viser at grunnfjellet ostenfor reiser sig i bratte berg hvor Jæren slutter. Ved foten av dem ligger Gansfjorden og en rekke vann. En svensk geograf, professor Ahlmann1, mener her er en forkastningslinje, og han opgir den gamle teori om strandflaten. Jeg har stykkevis tegnet 120 m kurven, som i syd markerer losmassene pa Hog-Jaren. På denne hylle i det faste berg har isbreene likesom på Lista lagt igjen enorme losmasser. Ved boring efter kull pa garden Grodeland motte man det faste berg forst på 124 m's dybde. 相似文献
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《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(4):173-179
Mannella, S. Agricultural reality in Apulia. Norsk geogr. Tidsskr. Vol. 32, 173–179. Oslo. ISSN 0029-1951. A survey of agriculture in Apulia, Italy, is presented. Farm size and management are dealt with in some detail. It is maintained that in spite of indications of changes from extensive to more intensive types of cultivation the present very nucleated settlement pattern will remain. 相似文献
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International Conference on Land Use/Cover Change Dynamics——First Circular Announcement(LUCCD''2001)
《地理学报(英文版)》2001,(1)
Organized by: Beijing Normal University, National Natural Science Foundation of China Hosted by: Institute of Resources Science, Beijing Normal UniversityKey Laboratory of Environmental Change and Natural Disaster, Ministry of Education of ChinaTopics:1) Detecting and monitoring LUCC2) Temporal-spatial characteristics in LUCC3) Driving model for LUCC4) Forecasting and modeling LUCC 5) Phenological and biochemical response on LUCC6) Regional LUCC and microclimate 7) LUCC i… 相似文献
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1990—2005年疏勒河流域土地利用/覆盖变化分析 总被引:7,自引:2,他引:5
选择疏勒河流域为研究区域,利用1990年TM、2000年ETM和2005年TM影像为信息源,应用地理信息系统和遥感技术,提取三期疏勒河流域土地利用信息,并对土地利用动态进行了分析。结果表明,近15 a来,疏勒河流域土地利用变化缓慢,土地利用格局没有发生显著变化;不同土地利用类型中,耕地面积和建设用地增加较多;林地、草地面积减少;水域在1990—2000年间减少,2000—2005年间增加;未利用地在1990—2000年之间增加,2000—2005年之间减少。 相似文献
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2001年—2009年中国及周边国家土地利用/覆盖变化分析 总被引:1,自引:1,他引:0
土地利用/覆盖变化能一定程度上反映国土开发变化特征,如何将传统的土地利用/覆盖变化研究与面向周边的国家区域发展战略相结合,成为土地利用/覆盖变化研究的新问题。基于研究区2001年、2009年两期M0DIS土地利用/土地覆盖数据,对土地利用/覆盖变化的格局、过程、驱动力进行了分析,进而提出了未来双边合作的方向。结果表明:2001年-2009年期间,除了水域和林地面积减少以外,草地、耕地、建设用地、未利用地面积都是增加的;除全球环境变化等自然因素外,国家政策、人口增长、经济发展等人类因素是土地利用/覆盖变化的主要驱动力。未来我国应注重与俄罗斯、印度、哈萨克斯坦等周边国家在森工、农牧业、边贸往来等领域的开发合作,维护边疆稳定,实现双边共赢发展。 相似文献
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本文首先用统计方法,分析了秦岭—黄淮平原过渡带降水量和暴雨分布的特点,然后探讨了地形对降水过程的影响松制。 相似文献
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利用南极磷虾渔业科学观察员收集的南极磷虾生物学数据,在将研究区域划分成60'×30'精细尺度单元的基础上,分析了南奥克尼群岛南极磷虾种群捕捞群体年龄结构的时空变化。结果表明,2009/2010年度,南极磷虾体长范围为33.2—69.0 mm,平均体长为51.8 mm,优势体长组为52—60 mm(52.3%),另在44—48 mm有一个次峰区;2010/2011年度,体长范围为22.9—59.3 mm,平均体长为44.5 mm,优势体长组为42—50 mm(56.8%);2011/2012年度,体长范围为18.5—59.4 mm,平均体长为41.7 mm,优势体长组为36—46 mm(67.3%)。三个年度间南极磷虾体长频次分布呈显著性差异(p0.001),且不具相似性(PSI=41.25—73.42)。2009/2010—2011/2012年度各旬别磷虾体长组可分成3个组,其中2011年2月上旬和2012年3月中旬可划分为一组,2010年1月下旬至2月中旬以及2011年2月中旬可归为一组,这几个体长组均呈双峰分布,其他的体长组划归为一组。1+和2+龄虾大多出现在离南奥克尼群岛最近的水域,而离南奥克尼群岛较远的单元中则多为4+龄以上的磷虾个体。 相似文献
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为探明城市化进程对区域CO2排放的影响机制,本研究以中国东南沿海快速城市化地区福建省为研究区域,采用LMDI指数分解法,将福建省CO2排放分解为CO2强度效应(ΔCF)、能源结构效应(ΔCN)、经济规模效应(ΔCY)、能源强度效应(ΔCI)和人口规模效应(ΔCP)5个影响因素,探讨福建省1978—2010年期间CO2排放的驱动机制.结果表明:1978—2010年期间,福建省CO2排放增加了5 817.10×104t,年均增长率为8.87%,高于全国平均水平;推动福建省CO2排放增加的核心因素是经济规模扩张和人口增加,而抑制CO2排放增长的主要因素为能源强度的下降,能源消费结构和CO2排放强度变化不是福建省CO2排放变化的主要原因.比较不同城市化阶段发现,经济规模效应对CO2排放的促进作用逐渐增大,能源强度抑制CO2排放增长的贡献逐渐降低. 相似文献
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Poul Ove Pedersen Viggo Hansen lektor dr. scient. Christian Wichmann Matthiessen 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):71-79
Danish Journal of Geography: 71–82, 1995. This paper presents two mega events as tools in the strategic planning of the Copenhagen area. Due to growing inter-metropolitan competition, increasingly offensive and complex means are applied. This demands strong leadership, stable longterm planning and willingness to accept the costs in order to reach the objectives. Marketing versus strategic planning is discussed. The general position of Copenhagen in the European urban system gives perspective to a potential change on the South Scandinavian urban scene. New instruments of strategic planning in Greater Copenhagen are introduced. The competitive level of Copenhagen is analyzed in relation to Stockholm, Berlin and Hamburg. Two examples of mega events are discussed that represent typical elements in urban competition: cultural events and infrastructure improvements. 1) Copenhagen as ‘The cultural City of Europe’ in 1996 represents a temporary mega event. 2) The planned bridge between Copenhagen and the south Swedish city of Malmö, combined with Swedish entrance into EU, opens up for development of the first cross-national integrated large-city region outside the European centre. This is an example of a mega event which will alter the scene permanently. Both events are important issues used in developing a growth strategy for Greater Copenhagen. But neither the cultural city nor the bridge may by themselves guarantee any advantages. It depends upon the ability of local actors to develop and promote the quality of their city. The paper represents a continuation and elaboration on earlier papers, see Matthiessen (1990, 1992) and Andersen &; Jørgensen (1994). 相似文献