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101.
世界地理研究回顾与展望——建所70周年世界地理研究成果与发展前景 总被引:3,自引:2,他引:1
中科院地理科学与资源研究所建所70年来,世界地理研究由于坚持了紧密为国家政治斗争和社会经济建设服务的正确方针,在地缘政治与地缘经济、国家与区域地理的综合研究、部门地理与专题研究、中外对比研究、世界地理知识普及等方面取得了一系列重要研究成果.研究工作中存在的问题为:超前性不够、系统性不强、研究手段落后、资料来源单一、成果... 相似文献
102.
103.
基于批判地缘政治学视角解读经典地缘政治理论 总被引:26,自引:7,他引:19
大国间的争霸与兴衰更替,无不受地缘法则的支配。地理学者应紧跟时代的步伐,准确把握国家利益之所在,抓住机遇为民族伟大复兴做出贡献。但是,缺乏对地缘政治学的历史和哲学的批判将不能准确理解和有效实践地缘政治理论。本文简要介绍了批判地缘政治学的发展,总结了批判地缘政治学的3个特点,据此对4个经典地缘政治理论进行了解读。为了简化解读过程,首先提出了一个解读4个经典地缘政治理论的分析框架;其次根据这个分析框架重点解读了麦金德的"历史的地理枢纽";最后对4个经典地缘政治理论进行了批判性总结。通过批判性解读,得出经典地缘政治理论既有科学性一面,也有假说性和理念性的一面。经典地缘政治理论构建是基于国际地缘格局、国家利益空间分布、国家间空间冲突而构建的,并展现了理论建构者的身份,体现了地缘政治理论的历史性、社会性、情境性和地理知识—权力结构。 相似文献
104.
《1:100万中国国界线画法标准样图》(简称“标准样图”)是经过多年辛勤工作而精心编制的,具有权威性的国界画法标准样图。它是编绘和审查1:100万或更小比例尺地图上国界线画法的基础和依据。为了更好地保存和充分利用这套宝贵资料,将其进行了数字化处理,为今后建立审图办公自动化系统奠定了基础。首先分析了“标准样图”的概况和基本特性,然后详细介绍了对其进行矢量化的一系列技术规定以及栅格数据的处理方法,最后对该数据成果进行了实用性分析。 相似文献
105.
An understanding of temporal evolution of snow on sea ice at different spatial scales is essential for improvement of snow parameterization in sea ice models. One of the problems we face, however, is that long‐term climate data are routinely available for land and not for sea ice. In this paper, we examine the temporal evolution of snow over smooth land‐fast first‐year sea ice using observational and modelled data. Changes in probability density functions indicate that depositional and drifting events control the evolution of snow distribution. Geostatistical analysis suggests that snowdrifts increased over the study period, and the orientation was related to the meteorological conditions. At the microscale, the temporal evolution of the snowdrifts was a product of infilling in the valleys between drifts. Results using two shore‐based climate reporting stations (Paulatuk and Tuktoyuktuk, NWT) suggest that on‐ice air temperature and relative humidity can be estimated using air temperature recorded at either station. Wind speed, direction and precipitation on ice cannot be accurately estimated using meteorological data from either station. The temporal evolution of snow distribution over smooth land‐fast sea ice was modelled using SnowModel and four different forcing regimes. The results from these model runs indicate a lack of agreement between observed distribution and model outputs. The reasons for these results are lack of meteorological measurements prior to the end of January, lack of spatially adequate surface topography and discrepancies between meteorological variables on land and ice. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
106.
根据2.5维面的设计思想及曲面可视化的方法,结合部分气象数据信息具有相同的经纬度范围和海拔高度的特点,构造了基于温度和可降水量的2.5维面,并重点提出在2.5维面上进行风场流线可视化的方法。实践证明,应用2.5维面分析气象数据在一定程度上平衡了运算量和可视化结果之间的矛盾,对地理环境气象数据的分析和比较有帮助作用。 相似文献
107.
Vegetation has a major influence on the water and energy balance of the earth's surface. In the last century, human activities have modified land use, inducing a consequent change in albedo and potential evapotranspiration. Linear vegetation structures (hedgerows, shelterbelts, open woodland, etc) were particularly abundant but have declined considerably over the past several decades. In this context, it is important to quantify their effect on water and energy balance both on a global scale (climate change and weather prediction) and on a local scale (soil column, hillslope and watershed). The main objective of this study was to quantify the effect of hedgerows on the water cycle by evaluating spatial and temporal variations of water balance components of a hillslope crossed by a hedgerow. Water flow simulation was performed using Hydrus‐2D to emphasize the importance of transpiration in the water balance and to evaluate water extraction from groundwater. Model validation was performed by comparing simulated and observed soil matrix potentials and groundwater levels. Hedgerow transpiration was calculated from sap flow measurements of four trees. Water balance components calculated with a one‐dimensional water balance equation were compared with simulations. Simulation runs with and without tree root uptake underlined the effect of hedgerow transpiration, increasing capillary rise and decreasing drainage. Results demonstrated that the spatial and temporal variability of water balance components was related to the hedgerow presence as well as to the meteorological context. The relations between transpiration, groundwater proximity and soil‐water availability determined the way in which water balance components were affected. Increased capillary rise and decreased drainage near hedges were related to the high transpiration of trees identified in this study. Transpiration reached twice the potential evapotranspiration when groundwater level and precipitation amounts were high. Water balance analysis showed that transpiration was a substantial component, representing 40% of total water output. These results may offer support for improving hydrological models by including the effect of land use and land cover on hydrological processes. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
108.
介绍了全国第二次土地调查项目中调绘底图生产、土地调查、田坎系数测定、农村宅基地调查等关键环节,结合实际生产,分析了各环节的重要性及实施情况。 相似文献
109.
China lies in East-Asian monsoon region,which is one of the well-known active monsoon zones around the world.Monsoon anomaly results in frequent natural disasters,such as drought,torrential rain and flood.In 1998,joint intensified observations for 4 major meteorological scientific experiments have been carried out over Chinese major monsoon affected areas.A number of valuable data have been obtained and some observational facts have come out after initial analysis.The present paper is to give an introduction to the 4 major meteorological scientific experiments conducted in 1998 in China.including its origin and scientific goals,implementation and planning,equipment and progress,and initial findings from the important observational facts.It aims to provide a comprehensive report on the progress of the above experiments for those who are interested in. 相似文献
110.
The industrial fisheries of Fiji have had mixed fortunes. The fresh fish export industry has grown rapidly in importance so that fisheries is now the third most valuable export industry; its positive effect on the economy is mainly in the increase in the purchase of goods and services, such as air freight. The present ‘hands off’ policy by government in the fresh fish export industry should continue until the industry matures. In the longer run, ad valorem royalties should be considered as a mean of capturing resource rents. The government-owned export cannery has been in financial decline, and the maintenance of the social benefits of regional employment generated by the cannery has come at a high cost to government coffers. The future of the cannery, now leased to a private operator, is clouded by the uncertainty of the continuity of concessional access to European markets beyond the year 2000. The main task faced by government is the management of fisheries and fish stocks. The management of the inshore fisheries — vital to the needs of a large proportion of the population — needs additional resources. The capability for management of the industrial fisheries, necessary to maximise long term public benefits, would be enhanced by full cost recovery through a user pays policy. This article is based on a paper presented to the Fiji Update seminar, held at the National Centre for Development Studies, the Australian National University, Canberra, on 19 June 1998. The author wishes to thank Mr Krishna Swamy, Senior Fisheries Officer in the Fiji Fisheries Division, and Mr Grahame Southwick, Managing Director of the Fiji Fish Company Ltd, for their generous provision of information for the preparation of this paper; and Mr Joeli Veitayaki, Coordinator of the Ocean Resources Management Programme, University of the South Pacific, for helpful comments. Any errors or omissions are the author’s responsibility, however. 相似文献