极端气温和极端降水复合事件的气候特征

基于1961-2014年的中国台站资料,侧重探讨极端气温和极端降水复合事件的气候特征。结果表明,基于客观方法检测出四类极端复合事件：暖湿、暖干、冷湿和冷干。四类事件的频发区分别位于东北地区、华南地区、西藏及华南地区和长江以南及云贵高原一带。全国暖湿、暖干事件频数呈增加趋势,春夏季频发;冷湿事件频数在西藏东北一带呈增加趋势,而在长江流域呈减少趋势,夏秋冬季频发;冷干事件频数呈减少趋势,秋冬季频发。四类极端复合事件经验正交分解的时间序列主模态均表现为年代际信号。进一步分析四类复合事件与能源消费量的联系表明,极端湿事件与能源消费量呈正相关,而极端干事件则相反。     

气候变化对天津市不同节能水平建筑制冷采暖能耗的影响

利用天津市地面气象观测站1961—2017年逐小时观测资料,通过TRNSYS软件,对不同节能水平办公建筑供热和制冷能耗,以及居住建筑供热能耗进行动态模拟,定量评估了气候变化对天津市不同节能水平建筑能耗的影响。结果表明：在供暖期和制冷期,温度均呈现显著上升的趋势,而太阳辐射则呈现下降的趋势,受其影响,1961—2017年办公和居住建筑供热能耗呈现显著下降的趋势,制冷能耗呈现微弱的上升趋势,但气候变化对供热能耗的影响要明显强于制冷能耗;随着建筑节能水平的提升,供热和制冷能耗均有一定程度的下降,其中供热能耗的降幅尤为明显,四步节能居住建筑相比于一步到三步节能居住建筑,供热能耗分别下降了53.56%、50.13%和21.25%。对新建建筑及既有建筑的节能改造,应充分考虑不同节能水平对建筑能耗的影响,结合实际需求酌情进行升级改造。除此之外,建筑节能水平的提升,会使其供热和制冷能耗变化量随温度的上升而减小,说明其对气候变化的敏感性在逐渐减弱。因此,提高建筑节能水平,可以更好的应对气候变化,保证其在未来的使用中耗能更低。     

Tele-connecting local consumption to global land use

Globalization increases the interconnectedness of people and places around the world. In a connected world, goods and services consumed in one country are often produced in other countries and exchanged via international trade. Thus, local consumption is increasingly met by global supply chains oftentimes involving large geographical distances and leading to global environmental change. In this study, we connect local consumption to global land use through tracking global commodity and value chains via international trade flows. Using a global multiregional input–output model with sectoral detail allows for the accounting of land use attributed to “unusual” sectors – from a land use perspective – including services, machinery and equipment, and construction. Our results show how developed countries consume a large amount of goods and services from both domestic and international markets, and thus impose pressure not only on their domestic land resources, but also displace land in other countries, thus displacing other uses. For example, 33% of total U.S. land use for consumption purposes is displaced from other countries. This ratio becomes much larger for the EU (more than 50%) and Japan (92%). Our analysis shows that 47% of Brazilian and 88% of Argentinean cropland is used for consumption purposes outside of their territories, mainly in EU countries and China. In addition, consumers in rich countries tend to displace land by consuming non-agricultural products, such as services, clothing and household appliances, which account for more than 50% of their total land displacement. By contrast, for developing economies, such as African countries, the share of land use for non-agricultural products is much lower, with an average of 7%. The emerging economies and population giants, China and India, are likely to further increase their appetite for land from other countries, such as Africa, Russia and Latin America, to satisfy their own land needs driven by their fast economic growth and the needs and lifestyles of their growing populations.     

A visco‐plastic constitutive model for granular soils modified according to non‐local and gradient approaches

An already available non‐associated elastic–viscoplastic constitutive model with anisotropic strain hardening is modified in order to describe both the constitutive parameter dependency on relative density and the spatio‐temporal evolution of strain localization. To achieve this latter goal, two distinct but similar approaches are introduced: one inspired by the gradient theory and one by the non‐local theory. A one‐dimensional case concerning a simple shear test for a non‐homogeneous infinitely long dense sand specimen is numerically discussed and a finite difference scheme is employed for this purpose. The results obtained by following the two different approaches are critically analysed and compared. Copyright © 2001 John Wiley & Sons, Ltd.     

BOOK REVIEWS

Books reviewed in this article: Boundary Control and Legal Priniciples . Curtis M. Brown , Walter G. Robillard and Donald A. Wilson . Lost Initiatives: Canada's Forest Industries, Forest Policy, and Forest Conservation . R. Peter Gillis and Thomas R. Roach . The Navajo Atlas: Resources, People, and History of the Dine Bikeyah . James M. Goodman . The City and the Sign . M. Gottdiener AND Alexandros Ph . Lagopoulos , EDS. The Comfortable House: North American Suburban Architecture 1890–1930 . Alan Gowans . Arabic-Islamic Cities. Building and Planning Principles . Besim Salim Hakim . Contemporary Climatology . Ann Henderson -Sellers and Peter J. Robinson . A Trace of Desert Waters . Samuel G. Houghton . Geography, Resources and Environment. Vol. 1: Selected Writings of Gilbert F. White. Vol. 2: Themes from the Work of Gilbert F. White . Robert W. Kates AND Ian Burton , ED. Spatial Dimensions of Unemployment and Underemployment (A Case Study of Rural Punjab) . Gopal Krishan . Maps of the Holy Land: Cartobibliography of Printed Maps, 1475–1900 . Compiled by Eran Laor , assisted by Shoshana Klein . The Geography of Third World Cities . Stella Lowder . A Perspective on U.S. Farm Problems and Agricultural Policy . Lance Mc Kinzie , Timothy G. Baker AND Wallace E. Tyner . Soil Erosion and Its Control. R.P.C . Morgan , ED Geopolitics . Patrick O'Sullivan . Landscape, Meanings and Values . Edmund C. Penning -Rowsell AND David Lowenthal , EDS.     

海底热流长期观测系统研制进展

浅海和俯冲海沟等海域,不仅是矿产和油气资源主潜力区,也是构造地震频发区,其浅表热流和深部温度信息对于了解板块俯冲和岩浆活动等过程至关重要.这些区域浅层地温场和热流场受到底水温度波动(BTV)强烈扰动,其背景热流需由长期观测来获取.在全面分析了国内外海底热流长期观测技术特点后,我们提出了系缆式海底热流长期观测方案,201...     

利用中心差分法进行GPS定速时最佳点数的选取

分析了利用中心差分法进行GPS定速时的主要误差来源,证明了当数据采样率一定时,增加中心差分法的点数可减少微分过程中的截断误差,但同时会放大导出相位率的观测误差,得出中心差分法的最佳点数应使这两种误差之和最小的结论。实验结果表明,当数据采样间隔为1s、载体平均速度和加速度为20m.s-1和0.2m.s-2时,9个点的中心差分法定速精度最高。     

非洲粮食问题的时空演化研究

非洲粮食生产与发展面临着诸多的困难与挑战,其粮食问题一直是国际社会关注的热点之一。本文研究的非洲粮食问题主要是指其粮食生产、消费及其自给能力方面存在的问题,从时间与空间视角对非洲粮食此类问题的演化过程和成因进行了初步探讨。时间视角上,考虑到20世纪90年代中期到21世纪初期非洲粮食问题表现较为典型,同时限于相关数据获取因素故,仅研究了1994-2007年,非洲粮食生产量、粮食消费量及生产性粮食缺口量的演化;空间视角上,从整体与区域两个层面,探讨了非洲不同粮食自给类型国家的空间差异及演化。最后提出解决非洲粮食问题的相关对策与建议。     

中国原油进口风险度以及对国内不同区域的影响分析

1993年中国开始从原油输出国变为原油输入国,到2010年,中国的原油进口依赖度高达53%。原油进口来源国的社会经济稳定性、原油运输线路的安全性影响到中国原油进口的安全性。本文根据ITIRI的综合国际贸易投资风险指数和原油运输线路的安全性,设计了中国从其主要原油进口来源国进口原油的风险指数。然后分析了中国各省级行政区对原油进口消费的依赖度,中国六个大区石化工业和八个石油化工基地对进口原油的依赖程度。从而分析了它们对进口原油风险的敏感度。本研究的结论是:第一,中国重要的原油进口来源国比较集中,且集中在社会经济不十分稳定的国家。第二,原油进口风险对沿海地区经济的影响远高于对内陆地区的影响。第三,沪宁杭、琼粤闽和长江中游石化基地是受原油进口风险影响最大的三个基地。根据这些结论,本文提出两方面建议:第一,建议中国原油进口来源与运输方式尽量多元化,以规避风险。第二,中国原油战略储备基地应考虑对原油进口风险敏感度大的地区。