日本经济地理学的发展、研究动态及其借鉴   总被引：2，自引：0，他引：2  

李国平 《世界地理研究》2006,15(3):29-37

日本经济地理学始于20世纪20年代后期。自1954年日本经济地理学会创立以来,经济地理学先后经历了起步阶段、发展阶段和转换阶段。在起步阶段,区位理论和区域经济地理成为经济地理学研究的重点;在发展阶段,主要是致力于发展独自的理论,地域构造论和地域经济论成为经济地理学研究的主要内容;而在转换阶段,主要是引进欧美经济地理学的最新成果,经济空间系统论成为研究的主要内容。日本经济地理学在全球化、信息化以及人文化的背景下,在研究方法论上和研究内容上均发生很大变化,主要体现为如下五个转变:①重新构筑经济地理学的理论框架,从“地域构造论”向“经济空间系统论”的转换;②扩大经济地理学的研究对象——经济现象,将社会、政治、制度、文化等纳入研究视野,从狭义的经济地理学向广义的经济地理学——社会经济地理学转换;③从地方尺度向全球尺度研究的转换;④从物质的生产和流动的空间过程及空间结构向非物质方面的转换;⑤从致力于发展独自的理论向注重和欧美经济地理学前沿研究领域相接轨的转变。日本经济地理学发展变化与最新研究动态对于同样处于转换期的中国经济地理学具有较大的借鉴意义。  相似文献   

Diatom Paleolimnological Record of Holocene Climatic and Environmental Change in the Altai Mountains, Siberia     

Karlyn S. Westover  Sherilyn C. Fritz  Tatyana A. Blyakharchuk  Herbert E. Wright 《Journal of Paleolimnology》2006,35(3):519-541

The sedimentary diatom records of three shallow lakes in the Altai Mountains, southern Siberia, were examined to assess the nature and timing of Holocene environmental changes. Few paleoenvironmental records, especially reconstructions not based on pollen, have been reported from this region. The lakes differ in elevation, annual precipitation, and catchment vegetation. Diatom assemblages in all lakes were dominated for the entire period of record by small benthic species of Pseudostaurosira Williams & Round, Staurosira Ehrenberg, and Staurosirella Williams & Round. Planktonic taxa only occur in very low abundances (<5%). The most diverse diatom flora was found in Dzhangyskol, which is situated at the lowest elevation within a forested catchment. A lack of detailed information on the ecological preferences of the dominant taxa and the complexity of environmental drivers make direct interpretation of the diatom record difficult. However, other proxies suggest that dramatic shifts in dominance between Staurosira elliptica and Staurosirella pinnata in Grusha Ozero reflect millennial-scale variability in climate. Together, chironomids and diatoms provide evidence of a cooling possibly correlative to the Younger Dryas Stade and subsequent early-Holocene warming consistent with pollen evidence of afforestation, which also is likely linked to increased humidity. By ~6000 cal year BP, the transition to a cooler, more continental climate had begun. The diatom record of Akkol shows significantly less variation in diatom community composition, but biogenic silica accumulation rates, a proxy for diatom productivity, appear to reflect climatic variability driven by insolation trends over the past 8000 years. Long-term variability in Dzhangyskol is not clearly linked to climate.  相似文献   

河流水质时空变化及其受土地利用影响的研究——以深圳市主要河流为例   总被引：23，自引：0，他引：23       下载免费PDF全文

岳隽  王仰麟  李正国  张源  卜心国 《水科学进展》2006,17(3):359-364

从深圳市的现实研究需求出发,在对地表水体主要水质指标因子分析的基础上,研究了深圳市境内五个集雨面积大于100 km2的河流近10年的水质时空变化特征。然后结合5个流域的土地利用详查数据,应用统计分析和空间分析方法论证了流域内土地利用类型与河流水质关键指标之间的相关关系。研究结果表明,从1996-2004年深圳市5个主要河流的有机物污染程度有不断增加的趋势,不同时间段内5个流域的耕地、园地和建设用地的数量对相应河流水质的有机物污染有明显的正效影响作用。因此为了制定和实施合理的水环境保护对策,需要对流域内土地利用结构进行优化调整,以期构建流域尺度上水土资源协调发展的可行预案。  相似文献   

河流环境流量法研究进展   总被引：4，自引：0，他引：4       下载免费PDF全文

桑连海  陈西庆  黄薇 《水科学进展》2006,17(5):754-760

回顾了20世纪80年代以来,国内外在河流环境流量法方面的研究进展,包括研究现状、方法类别及发展趋势。在国外,从考虑单一水文要素的水文学法,到考虑多学科交叉的整体分析法,逐步建立起一套完整的方法研究体系,今后发展趋势是通过国际间的合作研究,开发满足不同国家国情和水情特点的综合环境流量法。在国内,研究尚处于起步阶段,大多停留在定性分析水平上,定量分析,计算比较简单,主要采用的是水文学法,如Tennant法、7Q10法等,今后的研究方向一方面要加强基础研究工作,另一方面要根据本国(或流域、或地区)特点开发出适合于国情和水情的环境流量法,研究地区也应从干旱半干旱的北方地区转移到水资源较为丰富的南方地区。  相似文献   

Observed Trends in Total Vertical Column Abundances of Atmospheric Gases from IR Solar Spectra Recorded at the Jungfraujoch     

E. Mahieu  R. Zander  L. Delbouille  P. Demoulin  G. Roland  C. Servais 《Journal of Atmospheric Chemistry》1997,28(1-3):227-243

Since 1984, about 15000 high quality infrared solar spectra have beenrecorded with state-of-the-art grating and Fourier transform spectrometersat the International Scientific Station of the Jungfraujoch, Switzerland.Nonlinear least squares spectral curve fitting of selected microwindowscontaining isolated and well characterized lines of 20 telluric gases haveallowed to retrieve their total vertical column abundances above thestation, leading to observational data bases essential to derive long- andshort-term changes experienced by these species during the last 12 years. Inthis paper, we focus on atmospheric gases of particular interest within thecontext of the EUROTRAC/TOR (Tropospheric Ozone Research) project; secularevolution as well as seasonal cycles of the minor constituentsCH₄, CO and of the trace gasesC₂H₆, OCS, C₂H₂, HCNand H₂CO are reported and discussed. The long-livedN₂O is included as a tracer of the dynamic activity of theatmosphere.  相似文献   

Geochemical trends of sequential lava flows from Meseta volcano, Guatemala     

Craig A. Chesner  Sid P. Halsor 《Journal of Volcanology and Geothermal Research》1997,78(3-4)

The Meseta and Fuego volcanoes closely overlap and collectively are known as the Fuego Volcanic Complex. Historic activity occurs exclusively at Fuego, the southern center, and consists of high-Al basalts. Meseta, the inactive northern center, is predominantly composed of basaltic andesites with minor basalt and andesite. A thick sequence of lava flows and dikes is exposed by a steep collapse escarpment on the east flank of Meseta. The upper 75% of the sequence was sampled from three interfingering stratigraphic sections consisting of 27, 10 and 4 lavas, respectively. Temporal geochemical trends of each section indicates a complex evolutionary history. A major trend toward more evolved compositions upward in the section is consistent with crystal fractionation. This trend is sharply interrupted by the youngest lavas which become distinctly more mafic in composition. Magma mixing is apparently the dominant magmatic evolution process that generated these lavas. The two trends have distinct Sr signatures that suggest a change in parental magma compositions. This abrupt change in composition is interpreted to signal high input rates of mafic magma into the subvolcanic magma chamber. These changes eventually led to sector collapse of Meseta volcano and deposition of the Escuintla debris avalanche. Eruptive activity then migrated to the Fuego volcano where historic activity is similar to that of Meseta immediately prior to its collapse.  相似文献   

Methane,carbon monoxide and methylchloroform in the southern hemisphere   总被引：1，自引：0，他引：1  

P. J. Fraser  P. Hyson  R. A. Rasmussen  A. J. Crawford  M. A. K. Khalil 《Journal of Atmospheric Chemistry》1986,4(1):3-42

New observational data on CH₄, CO and CH₃CCl₃ in the southern hemisphere are reported. The data are analysed for long term trends and seasonal cycles. CH₃CCl₃ data are used to scale the OH fields incorporated in a two dimensional model, which in turn, is used to constrain the magnitude of a global CH₄ source function. The possible causes of observed seasonality of CH₃CCl₃, CH₄ and CO are identified, and several other aspects of observed CH₄ variability are discussed.Possible future research directions are also given.  相似文献   

论21世纪遥感与GIS的发展   总被引：72，自引：9，他引：72  

李德仁 《武汉大学学报(信息科学版)》2003,28(2):127-131

在 2 0世纪 ,人类的一大进步是实现了太空对地观测 ,即可以从空中和太空对人类赖以生存的地球通过非接触传感器的遥感进行观测 ,并将所得到的数据和信息存储在计算机网络上 ,为人类社会的可持续发展服务。在短短的 3 0年中 ,遥感和GIS作为一个边缘交叉学科已发展成为一门科学、技术和经济实体。本文深入地论述了 2 1世纪中遥感的 6大发展趋势和GIS的 5个发展特征  相似文献   

Impact of Air Transport on Seasonal Variations and Trends of Surface Ozone at Kislovodsk High Mountain Station     

Oksana A. Tarasova  Nicolai F. Elansky  Gennady I. Kuznetsov  Irina N. Kuznetsova  Irina A. Senik 《Journal of Atmospheric Chemistry》2003,45(3):245-259

The impact of air transport on the surface ozone variations is analyzed at Kislovodsk High Mountain Station for the period 1989–1996 on the basis of 2D back trajectories. It was shown that the contribution of photochemical and dynamical processes is different for the different seasons. In summer months the surface ozone concentration is governed by photochemical ozone production in semi polluted air from the regions of Northern Caspian, Southern Ural and Volga region. Time of the seasonal ozone maximum appearance is defined by joint influence of the processes of photochemical production and destruction in the eastern sectors and advection from Ukraine and Central Europe. The value of the seasonal minimum is determined by the processes of ozone destruction in the air coming from northeastern direction in the stable frontal zone. Distribution of sectors of the air transport changes from year to year and it can partly explain strong negative trend of the surface ozone concentration at the site.  相似文献   

On Destructive Canadian Prairie Windstorms and Severe Winters     

Hage  K. 《Natural Hazards》2003,29(2):207-228

Raw data on tornadoes and other destructive windstorms in the provincesof Alberta and Saskatchewan, Canada, are analyzed for spatial variations and timetrends. All storms and a subclass of intense storms are analyzed separately. StatisticsCanada agriculture census data are used to correct storm frequencies for the absenceof reports from unoccupied land, for sampling network drift, and for changes in farmnumbers and sizes. These corrections eliminate an apparent tornado spatial frequencymaximum in central Alberta and reveal a minor temporal frequency maximum from1906 to 1940 followed by no apparent trend in time for all intense storms. The frequencies of reports of severe winters in rural community histories of Alberta and Saskatchewan are compared with mean winter temperatures at Edmonton and with a severe winter index derived from temperature and snowfall data. All temperature data were corrected for urban heat island warming by an adaptation of Oke's proposed logarithmic relation between heat island intensity and urban population. The index identifies in correct order of importance the three most frequently mentioned severe winters of 1907, 1920 and 1936. Ten-year averages of mean winter temperatures and the severe winter index from 1882 to 2001 seem to show wavelike time changes rather than a long-term trend.  相似文献