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1.
Derek Azar  David Rain 《GeoJournal》2007,69(1-2):23-43
The hazards of place framework developed by Cutter (1996) has been applied to several areas across the United States. This article tests the applicability of that model for analysis of hydrological disasters in the municipio of San Juan, Puerto Rico. San Juan is chosen because it combines many socioeconomic attributes of a developing area while offering data availability befitting its status as a US commonwealth. The interoperability of principal components and arithmetically based methods for producing a social vulnerability layer are examined. For both methods, a basket of commonly cited demographic variables representing social and economic vulnerability is extracted from Census 2000 sample (SF-3) data at the census block-group level of analysis. These results provide insight on the strengths and weaknesses of the methods both methodologically and regarding policy implementation. A look at the neighborhood of La Perla suggests complex local positive and negative effects of local processes on vulnerability not captured by demographic analysis. These effects relate to possible census undercounts in peripheral areas and uncaptured coping ability provided by social networks.  相似文献   

2.
Gridded population distribution data are finding increasing use in a wide range of fields, including resource allocation, disease burden estimation and climate change impact assessment. Land cover information can be used in combination with detailed settlement extents to redistribute aggregated census counts to improve the accuracy of national-scale gridded population data. In East Africa, such analyses have been done using regional land cover data, thus restricting application of the approach to this region. If gridded population data are to be improved across Africa, an alternative, consistent and comparable source of land cover data is required. Here these analyses were repeated for Kenya using four continent-wide land cover datasets combined with detailed settlement extents and accuracies were assessed against detailed census data. The aim was to identify the large area land cover dataset that, combined with detailed settlement extents, produce the most accurate population distribution data. The effectiveness of the population distribution modelling procedures in the absence of high resolution census data was evaluated, as was the extrapolation ability of population densities between different regions. Results showed that the use of the GlobCover dataset refined with detailed settlement extents provided significantly more accurate gridded population data compared to the use of refined AVHRR-derived, MODIS-derived and GLC2000 land cover datasets. This study supports the hypothesis that land cover information is important for improving population distribution model accuracies, particularly in countries where only coarse resolution census data are available. Obtaining high resolution census data must however remain the priority. With its higher spatial resolution and its more recent data acquisition, the GlobCover dataset was found as the most valuable resource to use in combination with detailed settlement extents for the production of gridded population datasets across large areas.  相似文献   

3.
Lise Tole 《GeoJournal》2002,57(4):251-271
This study uses MSS data to derive sub-national level deforestation rates at the constituency administrative level for Jamaica for 1987 and 1992. It then investigates the role of poverty and population in driving forest loss during this period by linking these estimates in a GIS with constituency level demographic and socioeconomic census data for the island. OLS regression results support the importance of population pressures and poverty in driving the destruction of Jamaica's forests and the relative contribution to deforestation of their various measures are noted and discussed. In addition to providing information on Jamaica's deforestation attributes, the study demonstrates how remotely sensed data can be used in conjunction with household census data to derive information on human-forest interactions at the sub-national level. A small simulation experiment based on regression results using key variables suggests that under any scenario, the impacts of key social and demographic changes on Jamaica's remaining forest cover may be substantial by the year 2010. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

4.
Bedford RD 《GeoJournal》1988,16(2):179-192
May 1987 is a month that will not be forgotten in the South Pacific. The first of two military coups d'etat led by Colonel Sitiveni Rabuka not only transformed the course of post-colonial political development in Fiji, but this event also had profound implications for international relations in the region. Co-incidentally, May 1987 was also the month when detailed results of Fiji's second national population census since Independence in 1970 became available. The 1986 census documents Fiji's population on the eve of a political revolution which has the potential to cause significant economic and social change. The demographic process most likely to be affected in the short-term by the coups is population movement, both within Fiji and to overseas destinations. This: paper examines developments in population movement between 1970 and 1986 with particular reference to an acceleration in levels of migration overseas by Indians and an exodus of Fijians from rural village communities for towns on Viti Levu and Vanua Levu. Trends in internal and international migration are evaluated at a range of spatial scales — national, regional and local. Some speculation on the effect of political and economic changes since May 1987 on these population movements attempts to provide a contemporary perspective on demographic developments over the last 15 years.  相似文献   

5.
A common issue in spatial interpolation is the combination of data measured over different spatial supports. For example, information available for mapping disease risk typically includes point data (e.g. patients’ and controls’ residence) and aggregated data (e.g. socio-demographic and economic attributes recorded at the census track level). Similarly, soil measurements at discrete locations in the field are often supplemented with choropleth maps (e.g. soil or geological maps) that model the spatial distribution of soil attributes as the juxtaposition of polygons (areas) with constant values. This paper presents a general formulation of kriging that allows the combination of both point and areal data through the use of area-to-area, area-to-point, and point-to-point covariances in the kriging system. The procedure is illustrated using two data sets: (1) geological map and heavy metal concentrations recorded in the topsoil of the Swiss Jura, and (2) incidence rates of late-stage breast cancer diagnosis per census tract and location of patient residences for three counties in Michigan. In the second case, the kriging system includes an error variance term derived according to the binomial distribution to account for varying degree of reliability of incidence rates depending on the total number of cases recorded in those tracts. Except under the binomial kriging framework, area-and-point (AAP) kriging ensures the coherence of the prediction so that the average of interpolated values within each mapping unit is equal to the original areal datum. The relationships between binomial kriging, Poisson kriging, and indicator kriging are discussed under different scenarios for the population size and spatial support. Sensitivity analysis demonstrates the smaller smoothing and greater prediction accuracy of the new procedure over ordinary and traditional residual kriging based on the assumption that the local mean is constant within each mapping unit.  相似文献   

6.
 The purpose of this study was to compare regional patterns of indoor radon concentration with uranium-bearing rock zones and county populations in Texas. Zones yielding radon concentrations that are relatively high for Texas include shale and sandstone in northwest Texas; red beds in north-central Texas; felsic volcanic rocks in west Texas; and sandstone, limestone, and igneous rocks in central Texas. Located in northwest Texas, only five of the 202 counties evaluated have mean indoor radon concentrations above 4.0 pCi l–1. Two of those counties have populations above the state median of 20 115. The highest county mean concentration is 8.8 pCi l–1. Results of this study suggest that (1) regional geology influences indoor radon concentrations in Texas, (2) statewide, the radon concentrations are relatively low, (3) highly populated counties do not coincide with regions of high indoor radon concentration, and (4) regions that may warrant further monitoring include northwest Texas and, to a lesser degree, west and central Texas. Received: 8 August 1995 · Accepted: 6 September 1995  相似文献   

7.
This paper examines the possible storm surge damage from a major hurricane to hit the Houston Metropolitan Statistical Area (MSA.) Using storm surge analysis on a unique data set compiled from the Texas Workforce Commission (QCEW), the paper estimates the expected industry-level damage for each county in the Houston MSA. The advantages of using GIS to analyze the expected storm surge damage estimation is that it provides an accurate estimation of the number of affected employees and probable wages losses, by industry and county, based on QCEW data. The results indicate that the ‘Basic Chemical Manufacturing’ and ‘Oil and Gas Extraction’ industries incur the highest employee and payroll losses while the ‘Restaurants and Eateries’ has the largest establishment damage if a major hurricane were to hit the Houston MSA.  相似文献   

8.
Space not only reflects social inequality, it also reinforces the advantages or disadvantages associated with social class. However, the study of how neighbourhoods affect their residents has only recently entered the debate on urban poverty in Latin America. We use 2000 data from the Brazilian population census, school census, and the state of São Paulo’s educational evaluation system to analyze the relationship between school infrastructure, school academic achievement, and the neighbourhoods in which these schools are located. Our analyses indicate that state-run elementary schools located in areas of concentrated poverty have lower academic achievement in mathematics tests and Portuguese than mixed and affluent areas of the city, even though these schools are all administered by the same government body. We end with a discussion of the relationship between Brazilian education policy and its influence on spatial differences in São Paulo State.  相似文献   

9.
The effects of urban development on the natural ecosystem and its link to the increased flooding in Houston, Texas were evaluated. Houston is suitable for this type of analysis due to its 1.95 million population, large geographic area and fast growth rate. Using neural network techniques, four Landsat Thematic Mapper images were grouped into five land use classes for the period 1984 to 2003: vegetation, bare ground, water, concrete and asphalt. Results show that asphalt and concrete increased 21% in the time period 1984–1994, 39% in 1994–2000 and 114%, from 2000 to 2003, while vegetation suffered an overall decrease. When change detection data are compared with runoff ratio data, a relationship between increased runoff and urban development is apparent, which indicates increased chances of flooding. Initial results of this work are made available to the public in GIS format via internet using Arc Internet Map Server (ArcIMS) at .  相似文献   

10.
A re-evaluation of the demographic risk per number of inhabitants due to volcanic eruptions in the Vesuvius area was made on the basis of the Census data of 2001. We introduced other variables (population density and number of houses) which permit to upgrade the existing models. Using the Geographical Information Systems (GIS) and particularly ArcGIS 9.0 software we have elaborated a land use map, an urbanization map and a series of new risk maps which lead us to obtain a map of what we call “social risk” due to volcanic eruptions, derived from the combination of the data used and the overlay of the maps. We have proposed an integrated model which can be easily updated to follow the evolution of the volcanic risk in the overpopulated Vesuvius area, with the aim of supporting the planning of Civil Protection and Local Authorities, for an evacuation scenarios and the possibility of taking into account the potential infrastructural damages. This methodology can be tested in other volcanic regions.  相似文献   

11.
Seasonal variation in aquatic food web structure at Mad Island Marsh, Matagorda Bay, Texas, was examined using dietary information obtained from the analysis of gut contents from large samples of fish and crustacean specimens. Unique aspects of this study include the use of large samples of consumer gut contents (n=6,452), long-term sampling (bimonthly surveys over 18 mo), and standard methods of data collection and analysis facilitating comparisons with other aquatic food webs. Dietary data were partitioned for analysis into warm (summer) and cold (winter) seasons. Most consumers fed low in the food web, with trophic levels ranging from about 2 to 3.5 during both summer and winter. Vegetative detritus was more important in macroconsumer diets than live algae and macrophytes. Low trophic levels of consumers reflected the important role of abundant detritivores (e.g., striped mulletMugil cephalus, Gulf menhadenBrevortia patronum, and macroinvertebrates) in linking detritus to top predators via short food chains, a finding consistent with many other estuarine food web studies. Despite changes in community composition and population size structure of certain species, most food web properties revealed comparatively little seasonal variation. The summer food web had more nodes (86), more links (562), a higher density of links as indicated by connectance (0.08), and a slightly higher predator: prey ratio (0.51) compared to the winter food web (75 nodes, 394 links, connectance = 0.07, predator: prey ratio = 0.47). Proportions of top (0.06–0.07), intermediate (0.75–0.76), and basal (0.19) species did not vary significantly between seasons, but mean trophic level was higher during summer. Addition of feeding links based on information from the literature increased connectance to 0.13 during both seasons; other web parameters had values similar to those obtained for our directly estimated food webs. Seasonal variation in food web structure was influenced by changes in community composition (e.g., influxes of postlarval estuarine-dependent marine fishes during winter), availability of resources (e.g., more submerged macrophytes and amphipods during summer), and size structure and ontogenetic diet shifts of dominant consumer taxa. Our findings suggest that some basic properties of estuarine food web are resilient to seasonal changes in population and community structures and food web architecture.  相似文献   

12.
This study estimates the excess mortality attributable to excessive heat events (EHEs) for forty major U.S. cities during 1975–1995 and 1975–2004. We calculate these results using the spatial synoptic classification method to identify EHE days. Step-wise regressions are then used to estimate the location-specific mortality algorithms that can account for the impact of the EHEs’ duration, severity, and timing. Our excess mortality results are expressed both as lives lost and associated mortality rates (excess deaths per 100,000 residents) using 2000 Census population estimates. Our results generally show a reduction in EHE-attributable mortality rates since 1996. Adjusting our results to account for changes in the average number of EHE days per year in each period does not affect this general conclusion. However, this adjustment has a considerable impact on a measure of the cities’ relative performance in terms of reducing this EHE-attributable excess mortality. Our results indicate there is promise for further reductions in EHE-attributable mortality from the approximately 1300 excess deaths per summer we identify using data from the 1975–2004 period. However, the magnitude of this result highlights the significant health burden of EHEs relative to other extreme weather events in the United States and suggests it is worthy of additional attention. Our results also raise important questions with respect to evaluating the performance of EHE notification and response programs and how EHE-attributable mortality should be estimated for future scenarios, notably for climate change projections.  相似文献   

13.
Luca Salvati 《GeoJournal》2016,81(2):319-332
In the recent decades southern European cities experienced morphological changes and a demographic transition towards zero (or negative) growth and aging. Population dynamics shifted from the impressive growth of the post-industrial period into recent de-concentration processes determining the spillover of commercial and residential settlements across the surrounding rural areas. Based on long-term demographic data, the present study hypothesizes that urban expansion did not follow a one-way linear path from compactness to dispersion while reflecting differentiated growth patterns based on the specific socioeconomic context at the local scale. Along a sufficiently long time period non-linear expansion waves alternating settlement densification and scattering are expected to be found especially in complex urban contexts such as those developed in the Mediterranean region. This hypothesis was tested for a paradigmatic case study in southern Europe (Athens, Greece) using demographic data covering 160 years (1848–2011). Urban growth in Athens was assessed through the analysis of long-term census data made available on a district level. These data provide information on the spatial distribution of resident population and characterize distinct expansion waves according to the dominant socioeconomic context. Results of the study were discussed in the light of the debate on future development of the Mediterranean cities and the (changing) economic relations with the surrounding region.  相似文献   

14.
 A thorough understanding of the characteristics of transmissivity makes groundwater deterministic models more accurate. These transmissivity data characteristics occasionally possess a complicated spatial variation over an investigated site. This study presents both geostatistical estimation and conditional simulation methods to generate spatial transmissivity maps. The measured transmissivity data from the Dulliu area in Yun-Lin county, Taiwan, is used as the case study. The spatial transmissivity maps are simulated by using sequential Gaussian simulation (SGS), and estimated by using natural log ordinary kriging and ordinary kriging. Estimation and simulation results indicate that SGS can reproduce the spatial structure of the investigated data. Furthermore, displaying a low spatial variability does not allow the ordinary kriging and natural log kriging estimates to fit the spatial structure and small-scale variation for the investigated data. The maps of kriging estimates are smoother than those of other simulations. A SGS with multiple realizations has significant advantages over ordinary kriging and even natural log kriging techniques at a site with a high variation in investigated data. These results are displayed in geographic information systems (GIS) as basic information for further groundwater study. Received: 27 August 1999 · Accepted: 22 February 2000  相似文献   

15.
NOAA’s National Geophysical Data Center is using state-of-the-art Internet tools for natural hazards education, public outreach, and access to natural hazards data. For example, NGDC acquires, processes, and provides access to geologic hazards event data that are useful in natural hazards risk assessment and hazards-related research. In addition, a collection of natural hazards slides and a teacher’s guide on volcanoes are available online. NGDC also created an online “Kids Hazards Quiz” to test the user’s knowledge of disaster safety information. An online Natural Hazards Data Resources Directory provides access to information and links to organizations that provide natural hazards data and information. Expanded access to these data and information by the public and researchers can increase public awareness of natural hazards, improve hazards research, and ultimately reduce the devastating impacts of natural disasters.  相似文献   

16.
This article examines the effects of watershed urbanization on stream flood behavior in the Los Angeles metropolitan region. Stream gauge data, spatially distributed rainfall data, land use/land cover, and census population data were used to quantify change in flood behavior and urbanization in multiple watersheds. Increase in flood discharge started at the very early stage of the urbanization when the population density was relatively low but the rate of increase of flood discharge varied across watersheds depending on the distribution of the imperviousness surface and flood mitigation practices. This spatial variability in rainfall–runoff indices and the increasing flood risk across the metropolitan region has posed a challenge to the conventional flood emergency management, which usually responds to flood damages rather than being concerned with the broader issues of land use, land cover, and planning. This study pointed out that alternative land use planning and flood management practices could be mitigating the urban flood implemented hazard.  相似文献   

17.
The present study examines the spatial dependency of soil organic matter and nutrients in paddy fields at three different scales using geostatistics and geographic information system techniques (GIS). The spatial variability of soil organic matter (SOM), total nitrogen (TN) and available phosphorus (AP) has been characterized using a total of 460, 131 and 64 samples that were, respectively, collected from the Hangzhou–Jiaxing–Huzhou (HJH) Plain (10 km), Pinghu county (1,000 m) and a test plot area (100 m) within the Pinghu county, Zhejiang province of the southeast China. Semivariograms showed that the SOM and TN had moderate spatial dependency on the large scale of HJH plain and moderate scale of Pinghu county with long spatial correlation distances. At the moderate scale of Pinghu county and the small scale of a test plot area, the AP data did not show any spatial correlation, but had moderate spatial dependency in HJH plain. Spherical and exponential variogram models were best fitted to all these soil properties. Maps of SOM and TN were generated through interpolation of measured values by ordinary kriging, and AP by lognormal kriging. This study suggests that precision management of SOM and TN is feasible at all scales, and precision management of AP is feasible at large scales.  相似文献   

18.
Risk assessment to China’s agricultural drought disaster in county unit   总被引：14，自引：7，他引：7  
Hao  Lu  Zhang  Xiaoyu  Liu  Shoudong 《Natural Hazards》2012,61(2):785-801
China faces drought disaster risk under the changing climate. Risk analysis is a suitable approach in order to design ex-ante measure able to anticipate effects of drought on agricultural production. In this article, with the support of historic drought disaster data from 583 agro-meteorological observations (1991–2009), a risk analysis method based on information diffusion theory was applied to create a new drought risk analysis model, and the risk of China’s agriculture drought disaster was evaluated on higher spatial resolution of county unit. The results show that in more than three hundred counties of China, risk probability was biyearly or annually when Drought Affected Index (DAI) was over 5%. When DAI was up to 40%, more than one hundred counties were prone to drought disaster annually or once every 5 years. This showed that the impact of drought disaster on China’s agriculture, whether in frequency or intensity, was large. With the different level of DAI, China’s agricultural drought risk pattern showed variable pattern characteristics. When DAI was low, the distribution of county agricultural drought risk in China presented the East–West pattern of differentiation, and high risk mainly lied in the eastern, low risk mainly in the western. On the other hand, when DAI was high, the distribution of county risk appeared a pattern of high in center, and the north areas higher than the south, increased gradually from southwest to northeast. Drought risk presents a clear zonal differentiation that may be result from stepped topography, different precipitation and hazard-affected bodies. Spread of high value area of drought risk in northern may be related to the southeast monsoon and ecological degradation in northern Ecotone.  相似文献   

19.
The sources of carbon, which fuel water column respiration, remain unresolved for most estuaries; our objective was to examine carbon dynamics in a shallow subtropical estuary. We sampled the Sabine-Neches estuary, Texas, during low (November 1999) and high (May 2000) freshwater inflow and measured stable carbon isotope ratios of the dissolved inorganic and orgnaic carbon (δ13C-DIC, δ13C-DOC), as well as quantifying accessory parameters (salinity, nutrients, total suspended solids, and photosynthetic pigments). Pigment analysis indicated that diatoms were the predominant phytoplankton. Data from the May 2000 sampling event exhibited conservative mixing, indicating that the system was acting as a conduit between the watershed and the Gulf of Mexico. During November, mixing was generally nonconservative indicating extensive recycling of allochthonous and autochthonous carbon sources. Our data imply that both carbon sources had similar isotope, ratios that made it impossible to unambiguously determine the dominant source supporting respiration. The nonconservative DIC concentration data indicating an autotrophic sink as well as the strong relationship between δ13C-DOC and chlorophylla, suggest that in situ production was an important component of the DOC pool. We hypothesize that uncharacteristically calm wind conditions during sampling may have promoted phytoplankton settling, removing autotrophs, from the water column, but leaving behind a dissolved biogeochemical signature. Interpretation of carbon dynamics may be confounded by spatial and temporal decoupling of producers and consumers from biogeochemical indicators.  相似文献   

20.
A paucity of literature currently exists pertaining to the high-resolution geographic distribution of metal contaminants across urban areas. Thousands of soil samples were collected across Syracuse, NY to secure empirical evidence about such geographic distributions. Metal measurements were made with XRF technology, with quality assessments based upon replicate samples as well as ICP technology summarized here. Both metal covariations and their spatial structure are described, followed by mapping of selected metal measurements based upon sample points, as well as census block group and census tract aggregates. A simple comparison is presented between certain of these empirical results and a selected non-urban landscape (a river floodplain). Finally, implications drawn from the empirical evidence presented include covariation assessments with selected census data that serve as surrogates for poverty.  相似文献   

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