加拿大人口发展的空间差异及其变化

本文主要根据2001年加拿大人口普查资料，分析加拿大人口发展空间差异的变化。加拿大人口总量已从20世纪初的快速增长，转为20世纪末的缓慢增长。人口主要分布于国土南部的大中城市，但大城市中心区人口增速低于边缘区、与新兴城市形成对比。目前，加拿大人口已严重老龄化，并在探索采取各种措施缓解老龄化所带来的各种社会压力。     

Simulating trends in poverty and income inequality on the basis of 1991 and 2001 census data: a tale of two cities

How much does the 2001 census tell us about the changes in people's life in British cities and regions since 1991? This paper attempts to answer this question by telling the stories of two British northern cities: Leeds and Sheffield. In particular, the paper investigates and compares socio-economic change in these cities on the basis of actual 1991 and 2001 census data as well as estimated non-census data. A static spatial microsimulation model is used to combine the outputs of the 1991 and 2001 censuses of UK population with data from the British Household Panel Survey (BHPS) data. In particular, selected Small Area Statistics (SAS) tables from the 1991 and 2001 censuses are used as constraints in the spatial microsimulation modelling exercise, which aims to reweight BHPS household records so that they satisfy these constraints. The paper briefly discusses the change in these census variables across different localities of the two cities. It is then shown how the changes in these variables affect the simulation of non-census variables. Further, the microsimulation model is used to estimate the trends in income inequalities and child poverty between and within the two cities. Finally, the paper discusses the implication of the research findings for policy formulation.     

The role of population change in widening the mortality gap in Scotland

The social gradient in health and mortality has been acknowledged for some time and, more recently, there is some evidence that the gap between the richer and poorer is widening in Britain. Other studies have also shown that health and mortality outcomes are worse in places that are experiencing population decline and better in places that are growing. This analysis examines, first, whether there is a mortality gap between the least and most deprived people in Scotland, second, whether this gap has widened since the 1980s and, third, whether the gap can be explained by patterns of population change. Our results demonstrate that the widening mortality gap in Scotland cannot be explained simply as an artefact of population change, even though it is widening most in those places that are experiencing population decline. This type of research is made possible by the reliable denominator population information provided in the 1981 and 2001 censuses.     

华东地区台风降水及影响降水因素的气候分析

分析了华东地区各类台风路径降水的气候概况和影响降水的因素，冷空气入侵、地形作用、水汽条件及影响时间的长短等都能影响台风的降水量。最后给出了两个可用于诊断预报台风降水的物理量，计算结果表明，热成散度预报正确与基本正确率为32/34。     

Fault population investigation and estimating magnitude of extension in Guma Graben, Central Afar, Ethiopia

Extension in the Afar depression occurs on steeply dipping normal faults of many scales. An estimate for cumulative extension can be derived by summing the heave of these faults using digital topographic data, supplemented by field observations of fault dip. If it can be established that the distribution of faults exhibits self-similarity, an estimate of the contribution from faults too small to appear on the digital imagery can be incorporated into the integrated estimate for cumulative extension. A field study of faulting was undertaken within the Dobe and Guma grabens of Central Afar. A fractal dimension of 0.48 was obtained for the measured population of fault throws (n = 92) in 3 traverses totaling 42 km, a value interpreted to represent the dominant contribution to extension from faults with large throw. The local extension rate across Guma graben is estimated to be between 0.06 and 0.24 mm/year. The higher topographic position of the floor of Guma graben, relative to the sediment filled, adjacent floors of Dobe and Immino grabens is perhaps an indication of a slower rate of extension across Guma graben as compared to Dobe and Immino grabens, assuming they all initiated at the same time.     

Decentralization of the Nation's Main Street: New Coastal‐Proximity‐Based Portrayals of Population Distribution in the United States, 1950–2000

Almost half a century has passed since Jean Gottmann coined the term “Megalopolis” in reference to the almost continuously urbanized stretch of land spanning the East Coast of the United States from southern New Hampshire to northern Virginia. Because a disproportionate concentration of population resided in this Megalopolis, the northeastern core enjoyed an economic and cultural supremacy, and he termed the Megalopolis “The Main Street of the Nation.” By the later 1960s and 1970s, however, population migration patterns began to reflect the influence exerted by the emergence of a second national core centered on the large metropolitan areas along the Pacific Coast, especially those of the Los Angeles and Bay Area conurbations in California. Although of different character, this burgeoning concentration of population, economic activity, and cultural influence may reflect the development of a West Coast Megalopolis that could soon rival the original Megalopolis of the Northeastern Corridor. Today, the U.S. population distribution is largely a bicoastal one. This article documents the emergence of this bicoastal population distribution. Using historical census data and GIS technology, we present a number of novel ways to graphically portray and examine this population redistribution phenomenon. The United States is not unique in witnessing an increasing share of its inhabitants clustering in coastal zones. Current critical policy concerns about the worldwide vulnerability of coastal populations have focused the need for better coastal population estimates and better mapping methods for portraying population redistribution trends.     

2003年淮河汛期一次中尺度强暴雨过程的诊断分析和数值模拟研究

2003年7月4—5日淮河流域发生了一次中尺度强暴雨过程,致使淮河洪水泛滥。这次暴雨过程由中尺度对流系统(MCS)以及因其发展而产生的低涡造成。通过对此次过程的诊断分析和新一代细网格WRF中尺度预报模式的数值模拟,研究了这次过程发生发展的机制。模拟结果较好地描述了本次暴雨及中尺度系统发生、发展的时空演变过程。分析结果表明:此次移动性暴雨过程的前期由不断向东移动发展的MCS造成,后期降水则由低涡切变线产生的中尺度低涡引起。同时,副热带高压明显偏西偏北,并维持较长时间,造成雨带一直维持在淮河流域。高层辐合中心的加强使低空急流不断增强,低空急流的增强进而引起低层辐合的加强,而低层辐合的加强以及上升运动的潜热释放导致低涡的发生,低涡形成及形成后移动缓慢,造成了淮河流域的大暴雨。高层中尺度辐散区的抽吸对低层中尺度涡旋的发生发展起到了促进和加强的作用。低层的中尺度辐合场和高层的中尺度辐散场的发展与耦合对中尺度系统的发展有很好的预示作用。低层中尺度辐合区的减弱预示着系统的衰减,西南偏西的中层相对干冷空气侵入并在梅雨锋前缘下沉促进了系统的衰减。     

云南省的人口规模及地区分布变化

云南省人口发展的区域差异是云南社会经济发展不平衡的重要表现之一，也是云南社会经济发展不平衡的重要原因之一。对云南省1990年第四次人口普查和2000年第五次人口普查数据进行实证分析和统计分布检验的结果表明，从第四次人口普查到第五次人口普查的l0年间，云南省人口在规模扩大的同时，人口的地区分布差异也进一步扩大。云南人口地区差异扩大的主要原因之一是各地区人口增长差异较大。实现云南社会经济的可持续发展，必须在有效控制人口总量增长的同时，高度重视对人口发展区域差异的合理调控。     

Population distribution and its change in Guangzhou city

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