岩溶IGCP国际合作30年与岩溶关键带研究展望

全球岩溶类型多样,对环境变化敏感,资源与环境问题突出,是地球关键带监测与研究的重点,IGCP661项目的执行为岩溶区关键带类型划分与监测对比研究提供了契机和国际合作平台。近30年岩溶IGCP执行始终强调岩溶系统与人类活动环境的相互作用,其轨迹实际上与地球系统科学到地球关键带理念是一脉相承的。IGCP299提出了岩溶形态组合概念,揭示各种岩溶形态与其形成环境之间的因果关系。岩溶动力系统(IGCP379), 岩溶生态系统(IGCP448)概念的提出有助于我们更好地理解岩溶系统的整体功能,及系统内水、生物地球化学过程、人类活动的相互作用,进而形成了一整套岩溶动力学研究方法体系。开辟了岩溶记录与全球变化、碳循环与应对气候变化、石漠化形成演变与生态修复等研究新领域,并取得了丰硕的研究成果,有力地推动了现代岩溶学的发展。      

ETHNIC AND NATIONAL IDENTITIES OF AFRICANS IN THE UNITED STATES*

ABSTRACT. The emerging scholarly literature on contemporary African migration to the United States has primarily focused on populations concentrated in large urban areas. In contrast, this study considers the experiences of African university students living in two distinctly different places, Eugene, Oregon, and Washington, D.C., to examine how the context of the local host community shapes ethnic and national identities. Specific contextual variations under consideration are the extent to which newcomers have contact with coethnics/conationals and access to material and nonmaterial culture. Results based on thirty‐six in‐depth interviews show that, despite easy access to coethnics, some students in the Washington metropolitan area readily identified with conationals. Likewise, in the absence of coethnics in Eugene, many students described strengthening national identities; and, in the absence of conationals, they have constructed panethnic African identities. Additional research into the experiences of newcomers in various host‐community contexts is needed.     

Searching for the Mecca of finance: Islamic financial services and the world city network

This paper presents an analysis of the geography of the booming 'Islamic financial services' (IFS) sector, which provides a host of financial services based on Islamic religious grounds. The relevance of such an analysis is discussed against the conceptual backdrop of the world city network literature. It is argued that a focus on the globalisation of the IFS sector may provide an alternative to hegemonic geographical imaginations of world city-formation through its focus on other forms of globalising economic processes and regions that do not commonly feature in this literature. Based on information on the location strategies of 28 leading IFS firms in 64 cities across the world, we analyse different features of this decentred global urban geography. Manama is hereby identified as the Mecca of the IFS sector, while other major Gulf cities such as Dubai and Abu Dhabi are also primary nodes in this urban network. Other major Middle East North Africa (MENA) cities such as Tehran follow suit, but also more traditional financial centres such as London are well connected.     

国际贸易中的隐含碳排放研究综述

通过总结最近国际上关于贸易隐含碳排放的研究进展,指出国际贸易对国家及全球的温室气体排放具有重要的影响。传统的基于领土范围的CO2排放统计方法极易歪曲一国CO2排放的真实情况,不仅会引起发达国家对发展中国家＂碳泄漏＂现象的发生,也会间接地导致全球CO2排放的增加。作为发展中国家的中国,由于对外贸易的快速发展及较高的能耗水平,事实上为国外,尤其为发达国家排放了数量巨大的CO2。中国不是其碳排放的唯一责任方。在未来的气候变化谈判中,国际贸易对国家及全球CO2排放的影响应被高度重视;发达国家应该在减少温室气体排放方面继续承担主导作用,同时也应该加大对发展中国家的先进生产技术的转让和财政支持;中国等发展中国家除了提高自身的生产效率和能源利用效率外,还应加强对贸易中隐含碳排放的研究,以可靠有利的数据为国家争取更大的发展空间。     

三亚市风景结构与城市旅游发展研究

城市旅游是区域旅游发展的主力,对城市旅游内涵的正确理解将对旅游产业的发展和城市风景建设具有重要意义。本文从三亚市的城市定位,风景结构和区域旅游发展方面进行分析,并提出相应的规划建议,以促进三亚城市旅游健康合理的发展。     

POTENTIAL EFFECTS OF CLIMATE CHANGES ON AQUATIC SYSTEMS: LAURENTIAN GREAT LAKES AND PRECAMBRIAN SHIELD REGION

The region studied includes the Laurentian Great Lakes and a diversity of smaller glacial lakes, streams and wetlands south of permanent permafrost and towards the southern extent of Wisconsin glaciation. We emphasize lakes and quantitative implications. The region is warmer and wetter than it has been over most of the last 12000 years. Since 1911 observed air temperatures have increased by about 0·11°C per decade in spring and 0·06°C in winter; annual precipitation has increased by about 2·1% per decade. Ice thaw phenologies since the 1850s indicate a late winter warming of about 2·5°C. In future scenarios for a doubled CO₂ climate, air temperature increases in summer and winter and precipitation decreases (summer) in western Ontario but increases (winter) in western Ontario, northern Minnesota, Wisconsin and Michigan. Such changes in climate have altered and would further alter hydrological and other physical features of lakes. Warmer climates, i.e. 2 × CO₂ climates, would lower net basin water supplies, stream flows and water levels owing to increased evaporation in excess of precipitation. Water levels have been responsive to drought and future scenarios for the Great Lakes simulate levels 0·2 to 2·5 m lower. Human adaptation to such changes is expensive. Warmer climates would decrease the spatial extent of ice cover on the Great Lakes; small lakes, especially to the south, would no longer freeze over every year. Temperature simulations for stratified lakes are 1–7°C warmer for surface waters, and 6°C cooler to 8°C warmer for deep waters. Thermocline depth would change (4 m shallower to 3·5 m deeper) with warmer climates alone; deepening owing to increases in light penetration would occur with reduced input of dissolved organic carbon (DOC) from dryer catchments. Dissolved oxygen would decrease below the thermocline. These physical changes would in turn affect the phytoplankton, zooplankton, benthos and fishes. Annual phytoplankton production may increase but many complex reactions of the phytoplankton community to altered temperatures, thermocline depths, light penetrations and nutrient inputs would be expected. Zooplankton biomass would increase, but, again, many complex interactions are expected. Generally, the thermal habitat for warm-, cool- and even cold-water fishes would increase in size in deep stratified lakes, but would decrease in shallow unstratified lakes and in streams. Less dissolved oxygen below the thermocline of lakes would further degrade stratified lakes for cold water fishes. Growth and production would increase for fishes that are now in thermal environments cooler than their optimum but decrease for those that are at or above their optimum, provided they cannot move to a deeper or headwater thermal refuge. The zoogeographical boundary for fish species could move north by 500–600 km; invasions of warmer water fishes and extirpations of colder water fishes should increase. Aquatic ecosystems across the region do not necessarily exhibit coherent responses to climate changes and variability, even if they are in close proximity. Lakes, wetlands and streams respond differently, as do lakes of different depth or productivity. Differences in hydrology and the position in the hydrological flow system, in terrestrial vegetation and land use, in base climates and in the aquatic biota can all cause different responses. Climate change effects interact strongly with effects of other human-caused stresses such as eutrophication, acid precipitation, toxic chemicals and the spread of exotic organisms. Aquatic ecological systems in the region are sensitive to climate change and variation. Assessments of these potential effects are in an early stage and contain many uncertainties in the models and properties of aquatic ecological systems and of the climate system. © 1997 John Wiley & Sons, Ltd.     

大地坐标系新探

论述了有关大地坐标系的几个问题,它们大都与国家大地坐标系有关;为了坐标系的维持与应用,提出2000中国大地坐标系应由至少2 000个国家级GNSS连续运行站和若干GNSS复测站的坐标和速度实现;认为大地参考架的更新周期取决于参考架的实现精度与具体应用的要求。为满足1∶1 000比例尺测图的需要,大地参考架的更新周期大约为30 a。同时还对"动态大地基准"的说法进行了评说。     

区域经济发展的知识动力及其多区位机制北大核心CSCD

在信息、劳动力、资本和商品等要素超具流动性的时代背景下,知识越发表现出一种邻近和远距离流动并存的多区位互动特征,并对区域经济发展产生重要影响。为此,论文首先围绕当前人类社会经济系统的一系列重要变化,并结合传统区域创新研究范式的内在缺陷,引介以知识组合为核心的区域知识动力学理论。在此基础上,尝试构建区域经济发展的多区位知识动力解析框架:通过引入信任机制和学习机制深度阐释正式/非正式制度和认知水平等地方情景因素对知识组合的影响机理;分别围绕外部知识关联和知识网络外部性探究多区位知识网络对区域产业比较优势演化和内生经济增长的作用机制。最后,从区域管治、区域战略导向、政策工具和知识影响4个维度归纳知识经济时代的区域治理逻辑。多区位知识动力框架推进了区域创新学派关于经济发展中知识动力问题的研究,有助于区域协同创新和经济高质量发展政策的科学制定。     

Hydrological Simulation Using TRMM and CHIRPS Precipitation Estimates in the Lower Lancang-Mekong River Basin

Satellite-based products with high spatial and temporal resolution provide useful precipitation information for data-sparse or ungauged large-scale watersheds. In the Lower Lancang-Mekong River Basin, rainfall stations are sparse and unevenly distributed, and the transboundary characteristic makes the collection of precipitation data more difficult, which has restricted hydrological processes simulation. In this study, daily precipitation data from four datasets(gauge observations, inverse distance weighted(IDW) data, Tropical Rainfall Measuring Mission(TRMM) estimates, and Climate Hazards Group InfraRed Precipitation with Stations(CHIRPS) estimates), were applied to drive the Soil and Water Assessment Tool(SWAT) model, and then their capability for hydrological simulation in the Lower Lancang-Mekong River Basin were examined. TRMM and CHIRPS data showed good performances on precipitation estimation in the Lower Lancang-Mekong River Basin, with the better performance for TRMM product. The Nash-Sutcliffe efficiency(NSE) values of gauge, IDW, TRMM, and CHIRPS simulations during the calibration period were 0.87, 0.86, 0.95, and 0.93 for monthly flow, respectively, and those for daily flow were 0.75, 0.77, 0.86, and 0.84, respectively. TRMM and CHIRPS data were superior to rain gauge and IDW data for driving the hydrological model, and TRMM data produced the best simulation performance. Satellite-based precipitation estimates could be suitable data sources when simulating hydrological processes for large data-poor or ungauged watersheds, especially in international river basins for which precipitation observations are difficult to collect. CHIRPS data provide long precipitation time series from 1981 to near present and thus could be used as an alternative precipitation input for hydrological simulation, especially for the period without TRMM data. For satellite-based precipitation products, the differences in the occurrence frequencies and amounts of precipitation with different intensities would affect simulation results of water balance components, which should be comprehensively considered in water resources estimation and planning.     

上海天文台2009年工作总结

总结了2009年度中国科学院上海天文台在科研、国际合作交流、人才培养和引进、佘山科技园区建设、科研管理、精神文明建设等方面取得的成果。