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1.
Forrest R. Pitts 《The Professional geographer》2013,65(3):422-423
This study examines the spatial distribution and impact of nonroutine accidental releases of hazardous materials relative to the demographic composition of residents in nearby communities. First, atmospheric dispersion modeling methods are used to delineate the impact zones of worst-case accidents in two New York counties over the last ten years. Next, using accidental reports for 1997, GIS and statistical operations are used at the census tract level of the two counties to determine whether these incidents disproportionately affected disadvantaged neighborhoods. The results suggest that the areas of high-impact from accidental releases of hazardous materials are best characterized by a large proportion of families below the poverty line, Hispanics, and other minorities. 相似文献
2.
In this article, we 1) develop and demonstrate an approach for assessing the population at risk to airborne releases of extremely hazardous substances, 2) examine the relationship between potential sources of chemical hazards and the special needs population in a medium‐sized metropolitan area (Cedar Rapids, Iowa), and 3) determine whether the distribution of environmental risks disproportionately impacts the special needs population. Our approach provides a comprehensive view of the risk burden imposed on the population by examining the effects of multiple sources of toxic releases. Disproportionate impacts are evaluated by comparing the existing distribution of the special needs population at risk to 1,000 randomly simulated distribution patterns. The results indicate that a significantly high proportion of the special needs population resides in areas susceptible to worst‐case toxic releases. 相似文献
3.
《Urban geography》2013,34(6):516-533
The distribution of toxic air releases in urban Texas counties is compared to socioeconomic patterns to identify inequitable risk burdens. Chronic and acute toxic airborne release patterns from 1987 to 1990 are compared to demographics for Metropolitan Area (MA) counties. Spearman rank correlation tests indicate that counties with higher percentages of Blacks and other minority groups are more likely to have higher numbers of acute and chronic toxic releases. Mann-Whitney U-tests were used to compare the race and per capita income ranks of the top and bottom 10 counties, which indicated that Blacks and other minority groups were more likely to be associated with airborne toxics. Further analyses explored these relationships at the census-tract level for three sample counties representing distinctly different proportions of Black population. Only one of the sample counties provides supportive evidence that Blacks and other non-Hispanic minorities are inequitably burdened by airborne toxic risk from toxic facilities. [Key words: environmental equity, toxic chemicals, air quality, risk, urban.] 相似文献
4.
广东省地质灾害较为常见,崩塌、滑坡、泥石流是其中比较严重的3种类型。基于现有的泥石流危险度评价原理和方法,建立了可用于广东省崩塌、滑坡、泥石流灾害危险性的评价模型。以全省88个县级评价单元为基础,根据崩塌、滑坡、泥石流灾害危险度评价结果,将广东省共分为3个危险等级区,其中高度危险区8个县,占总数的9.1%;中度危险区60个县,占总数的68.2%;低度危险区20个县,占总数的22.7%,据此制成广东省崩塌、滑坡、泥石流灾害危险等级图。高度危险区主要位于粤北山区,危险度数值介于0.6～0.72之间;中度危险区连片分布,是全省崩塌、滑坡、泥石流灾害的主体部分,危险度数值介于0.4～0.6之间;低度危险区集中分布在平原区及低平台地区,危险度数值介于0.31～0.4之间。采用1994―2009年广东省防灾减灾年鉴和广东省地质灾害防治规划(2001―2015年)中的统计数据,验证了本文的研究成果与实际情况具有较高的一致性。 相似文献
5.
The American Great Plains is a region dominated by a flat, treeless, semiarid environment that has challenged population settlement for over 140 years. As railroad companies successfully attracted pioneers to settle the land, state governments established hundreds of counties. Following Jeffersonian ideals, many of the counties were small in area so they could better serve the local agricultural‐based population. When states established these counties, they envisioned that the population would continue to grow and the Great Plains would become the breadbasket of North America. Unfortunately that did not materialize. A succession of hardships combined with serious environmental constraints has discouraged large‐scale settlement in the region. Many counties reached their maximum population in the early 1900s and their totals have decreased ever since (in some counties by as much as 60 percent to 80 percent). This has led a number of government officials to consider consolidating counties much like school districts have been combined. Using Logan and Gove counties in western Kansas as a case study, our purpose is to understand how attached people are to the county in which they live. Employing multiple methods, we gathered information about how different segments of the population regard their local county. We learned that changing computer technology and the Internet has the biggest impact on peoples' attachment to the county seat. 相似文献
6.
京津冀城市群县域尺度生态效率评价及空间格局分析 总被引：6，自引：3，他引：3
京津冀城市群地区是国家经济发展的战略核心区之一,其经济发展与资源环境关系是近年来地理研究的重点领域。本文以京津冀城市群县域为单元,利用PM2.5、NO2遥感反演等数据,设计资源投入—经济效益—环境影响复合生态效率评价指标体系,构建县域单元生态效率评价模型,并利用非期望产出SBM模型对生态效率进行了评价,运用空间自相关分析方法对生态效率的空间效应与空间关联模式进行了检验与分析。结果显示：①资源投入、经济效益与环境影响格局存在明显时空分异,高值区主要分布在京津唐三市及周边部分县区;②2006、2010、2014年3个时期京津冀城市群县域单元生态效率均值分别为0.324、0.305、0.347,总体水平较低,并呈现先下降后改善态势,区位、自然本底条件是导致生态效率空间差异的主要原因。③全局Moran's I指数分别为0.2539、0.3007、0.3088,表明县域单元生态效率存在空间正向集聚趋势;④县域单元生态效率正向集聚程度越来越显著,邻域单元生态效率差距则有所缩减。 相似文献
7.
利用旱涝县次建立历史时期旱涝指数序列的试验* 总被引：8，自引：4，他引：8
本文利用27万条自然灾害史料记载,整理出我国东部及南部85个地区的受灾县次记录,分析了这些记录的可靠性,建立了这些地区1471—1950年的旱涝指数序列,并以北京地区为例,详细说明了利用旱涝县次建立旱涝指数序列的过程,分析了这种方法的可靠性。 相似文献
8.
三峡库区秭归县和兴山县的土地利用 总被引：1，自引：0，他引：1
In this study the arable land changes in two counties (Zigui and Xingshan) in the Three Gorges Reservoir area in China are investigated. The statistical data fTom the officially published statistical books are used to study these changes in the two counties during the past 50 years since 1949. The changes of arable land, changes of arable land per capita, and changes of multiple crop index in Zigui and Xingshan counties are examined. Using an index method, we conclude that the two counties are critical in the sustainable utilization of arable land. 相似文献
9.
In this study the arable land changes in two counties (Zigui and Xingshan) in the Three Gorges Reservoir area in China are investigated. The statistical data from the officially published statistical books are used to study these changes in the two counties during the past 50 years since 1949. The changes of arable land, changes of arable land per capita, and changes of multiple crop index in Zigui and Xingshan counties are examined. Using an index method, we conclude that the two counties are critical in the sustainable utilization of arable land. 相似文献
10.
One of the most recognizable and important changes occurring in the West is rapid population growth. This article intends to address questions associated with whether patterns of population growth and income migration are associated with “new” and “old” West economies. Rural restructuring in the U.S. has created a group of counties with service‐based economies. In the Mountain West, a number of counties with service‐based economies are located in areas with high levels of environmental or natural amenities, creating what has been termed the “New West.” Migration to the rural parts of the Mountain West, and the income transfers associated with migration, are increasingly concentrated within these New West counties. Rapid population growth, the changing characteristics of in‐migrants, and their spatial concentration in New West counties provide a basis for conflicts over what the rural West is becoming. 相似文献
11.
《The Australian geographer》1995,26(1):71-86
The upper Nepean River has been progressively regulated for water supply to Sydney and Wollongong since 1886 by the Upper Nepean Water Supply Scheme which consists of four large dams, two small dams and two diversion weirs. Secular rainfall changes produced periods of high rainfall and large floods (flood‐dominated regimes) between 1857 and 1900 and 1947 and the present, and an intervening period (1901–46) of low rainfall and small floods (drought‐dominated regime). Upstream impoundment and flow regulation significantly reduced flood magnitudes for most return periods during both types of flood regimes. The probability distribution of mean daily flows was also changed significantly by flow regulation such that during the drought‐dominated regime, the high and low frequency flows were reduced substantially but the moderate frequency flows were increased due to dam releases; the change from a regulated drought‐dominated regime to a regulated flood‐ dominated regime resulted in a substantial increase in discharge for most durations; and increased water diversions to Wollongong during the current flood‐dominated regime produced a marked downward shift in the whole flow duration curve. Nepean Dam reduced downstream suspended sediment yields by two orders of magnitude because it traps in excess of 99 per cent of the inflowing suspended sediment load. Streamflow releases are urgently required from the two diversion weirs to improve downstream water quality and to ensure the viability of the resident ‘potentially threatened’ eastern Macquarie perch (Macquaria nov. sp.). 相似文献
12.
ABSTRACT. Declining populations, aging inhabitants and infrastructure, limited economic opportunities, and under‐ or unappreciated natural environments characterize a number of rural communities in the western United States. Faced with the challenges of providing for their residents, some of these communities have chosen to permit undesirable land‐use activities, including the disposal of hazardous or nuclear waste. Central to the development of such sites is how a place is perceived and portrayed. Our purpose in this article is to examine how a dominant perception and portrayal of one such place—Tooele County, Utah—was created and used to facilitate the development of hazardous‐waste‐disposal sites. We use the geographical concept of “place” to illustrate how meanings and values are attached to a region in order to justify its becoming what it is and how such views persist. 相似文献
13.
中国县域网络购物空间格局及其影响因素 总被引：1，自引：0，他引：1
基于阿里巴巴县域网络购物数据,分析中国1915个县域的网购格局,并利用地理探测器探讨其影响因素。结果表明：① 县域网购格局整体上以江浙为核心、从东部沿海向内陆扩散,但存在由东部沿海向华北地区延伸的高值条带及内陆散落状的高值区,低值集聚区主要在西南、东北地区。② 县域网购水平的核心影响因素是网商水平、城镇化水平、居民收入,二级影响因素是教育水平、信息化水平、物流发达程度,其他因素的影响较小。③ 不同地区县域网购水平的主要影响因素存在较大差异。除城镇化和受教育水平是所有县域的主要影响因素外,中部地区县域还受收入水平、信息化的影响,西部地区县域还受物流发达程度、经济水平、零售水平的影响,东部地区县域还受网商水平的影响。 相似文献
14.
长三角一体化区域城市商品住宅价格分异机理研究 总被引：4，自引：1，他引：3
城市住宅价格及其空间差异是21世纪以来引起城市地理学者持续关注的热点问题。以长三角135个区县为研究对象,在通过分异度指数测度发现2014-2016年各区县商品房价差异增大的基础上,以商品房单位面积成交均价为因变量,提取16项房价影响因素为自变量,通过逐步回归和地理加权回归进行定量分析。研究发现：高校资源、经济密度、房产政策、经济实力、公共服务投入、高端从业者占比和产业结构7项指标对房价分异的影响最显著,而各因素对区域内房价的影响程度均具有显著的空间不稳定性。进而,提出房价是城市经济、人力、社会和行政等资源丰度的货币化表达,区域房价分异是城市支配资源能力差异的综合反映,其中行政资源在各类资源中占据主导地位。由此判断,长三角各区县房价在短时期内较难实现“俱乐部收敛”,沪宁杭等核心城市与外围地区的房价差距可能会继续扩大。 相似文献
15.
Holly R. Barcus 《The Professional geographer》2007,59(3):298-315
This article evaluates the emerging Hispanic population in Appalachia, which nearly tripled in size to 465,000 between 1980 and 2000. Using 1980, 1990, and 2000 census data, changes in the geographic distribution of Hispanics and in the economic characteristics of counties with growth in Hispanic population are assessed. Results suggest that high‐growth counties are clustered in peripheral areas in the northern and southern subregions and are characterized by higher per capita income and greater economic viability than those areas with relatively low Hispanic population growth. 相似文献
16.
17.
ABSTRACT. Within the hazards‐ and disaster‐research community consensus exists as to factors that magnify or attenuate the effects of extreme natural events on local places. But less agreement and understanding exist concerning the methods or techniques for comparing hazard vulnerability within or between places, especially small‐island developing states. Using two Caribbean nations, Saint Vincent and Barbados, as study sites, we asked which island has the greater level of hazard vulnerability, and why. Results indicate that, although neither island has a large portion of its population living in extremely hazardous locations, Barbados has many more residents in risk‐prone areas. The methods used in this research provide valuable tools for local emergency managers in assessing vulnerability, especially through the delineation of highly vulnerable hot spots. They can also help donor organizations interested in vulnerability reduction on islands use their resources more efficiently. 相似文献
18.
"一江两河"地区县域经济发展水平的空间差异分析 总被引：2，自引：0，他引：2
以“一江两河”为研究区,选取人均GDP、农民人均年纯收入、城镇化水平等6项指标,采用量图分析法,探索了该区域18个县级行政区的经济发展水平;通过分析发现城关区和日喀则市属先进类型,经济发展速度和经济发展水平都较高;堆龙德庆县、墨竹工卡县等11个县为中等发展水平县,其中堆龙德庆县、墨竹工卡县、贡嘎县、乃东县、江孜县等5县为中等类型中较先进类型,尼木县、达孜县、琼结县、扎囊县、白朗县、拉孜县等6县为中等类型中较落后组;而曲水县、桑日县、林周县、南木林县、谢通门县等5县为落后类型。最后根据“一江两河”地区县域经济发展水平提出了各类型县域经济发展的途径和对策。 相似文献
19.
JOHN FRASER HART 《Geographical review》2001,91(3):525-543
ABSTRACT. The census concept of total cropland is a better measure of effective agricultural land than is total farmland, which includes extensive areas of woodland owned by farmers. The cropland area of the United States dropped from 478 million acres in 1949 to 431 million acres in 1997, for a net loss of less than 1 million acres, or roughly one‐fifth of 1 percent, per year. In the midwestern agricultural heartland most counties changed less than 5 percent in the half‐century, and more counties gained than lost. The West was a crazy quilt of change, and in the East most counties lost more than 10 percent. Major metropolitan counties lost a few percentage points more than did adjacent areas, but at a lower rate per capita than the nation as a whole. Most of the loss of cropland was in marginal agricultural counties with soils of low inherent fertility and topography unsuited to modern farm machinery. The loss of cropland to suburban encroachment may be cause for intense local concern, but attempts to thwart development cannot be justified on grounds of a net national loss of good cropland. 相似文献
20.
近20年珠三角城市群城市空间相互作用时空演变 总被引：11，自引：3，他引：8
利用改进的引力模型和潜力模型,结合GIS空间分析方法,从地级市和县域两个空间尺度分析了近20 a珠三角地区城市间相互作用的时空演变。结果表明:珠三角地级城市空间联系总体逐步加强,并充分体现出广州的中心城市地位;县域尺度上,空间联系强度较大的主要是各地市市区之间及广-佛都市区的县市间和各地市市区与其所辖县市之间,其它县市间联系强度则较小;珠三角核心区内大部分县市之间联系总体呈逐渐增强趋势,核心区外的县市之间及其与核心区内的县市间联系强度有升有降,规律性不明显。广-佛都市区和深圳-东莞-惠州都市区的城市潜力较大且变动较大,对外辐射带动作用强,其它城市潜力相对较小且变化不明显;珠三角城市潜力的区域不平衡态势明显,城市潜力的空间分异和空间辐射的特征与演变规律明显。 相似文献