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991.
Identification of Land-Cover Changes Through Image Processing and Associated Impacts on Water Reservoir Conditions 总被引:2,自引:0,他引:2
A temporal assessment of land-cover changes of the province Beykoz in Istanbul has been documented in this article. The study focuses on the acquisition and analysis of LANDSAT 5 TM images that reflect the drastic land-cover changes between the years 1984 and 2001 utilizing aerial photographs, orthophoto maps, standard topographic maps, and ground truth measurements. The status of the province, including its surrounding villages, were examined together with more specialized maps showing only the city center and part of the province that lies within the watershed of the Elmali Drinking Water Reservoir. The land distribution profiles were also calculated for each of the images to help authorities and decision-makers to better understand the main causes of such remarkable changes and to inform them of the changing quality conditions of the reservoir. Rapid, uncontrolled, and illegal urbanization accompanied by insufficient infrastructure has caused degradation of forests and barren lands in the province, especially within the past two decades. The proximity of the province to the reservoirs watershed, downtown Istanbul, and the transportation network has accelerated the land-cover changes whose adverse impacts on the reservoir water quality are sensed. It is intended that the data gathered and processed in this study will provide a basis for future sustainable urban planning and management activities. 相似文献
992.
Land-Use and Land-Cover Change in Montane Mainland Southeast Asia 总被引:12,自引:1,他引:12
This paper summarizes land-cover and land-use change at eight sites in Thailand, Yunnan (China), Vietnam, Cambodia, and Laos
over the last 50 years. Project methodology included incorporating information collected from a combination of semiformal,
key informant, and formal household interviews with the development of spatial databases based on aerial photographs, satellite
images, topographic maps, and GPS data. Results suggest that land use (e.g. swidden cultivation) and land cover (e.g. secondary
vegetation) have remained stable and the minor amount of land-use change that has occurred has been a change from swidden
to monocultural cash crops. Results suggest that two forces will increasingly determine land-use systems in this region. First,
national land tenure policies—the nationalization of forest lands and efforts to increase control over upland resources by
central governments—will provide a push factor making it increasingly difficult for farmers to maintain their traditional
swidden land-use practices. Second, market pressures—the commercialization of subsistence resources and the substitution of
commercial crops for subsistence crops—will provide a pull factor encouraging farmers to engage in new and different forms
of commercial agriculture. These results appear to be robust as they come from eight studies conducted over the last decade.
But important questions remain in terms of what research protocols are needed, if any, when linking social science data with
remotely sensed data for understanding human-environment interactions. 相似文献
993.
Habitat loss and modification is one of the major threats to biodiversity and the preservation of conservation values. We use the term conservation value to mean the benefit of nature or habitats for species. The importance of identifying and preserving conservation values has increased with the decline in biodiversity and the adoption of more stringent environmental legislation. In this study, conservation values were considered in the context of land-use planning and the rapidly increasing demand for more accurate methods of predicting and identifying these values. We used a k-nearest neighbor interpreted satellite (Landsat TM) image classified in 61 classes to assess sites with potential conservation values at the regional and landscape planning scale. Classification was made at the National Land Survey of Finland for main tree species, timber volume, land-use type, and soil on the basis of spectral reflectance in satellite image together with broad numerical reference data. We used the number and rarity of vascular plant species observed in the field as indicators for potential conservation values. We assumed that significant differences in the species richness, rarity, or composition of flora among the classes interpreted in the satellite image would also mean a difference in conservation values among these classes. We found significant differences in species richness among the original satellite image classes. Many of the classes examined could be distinguished by the number of plant species. Species composition also differed correspondingly. Rare species were most abundant in old spruce forests (>200 m3/ha), raising the position of such forests in the ranking of categories according to conservation values. The original satellite image classification was correct for 70% of the sites studied. We concluded that interpreted satellite data can serve as a useful source for evaluating habitat categories on the basis of plant species richness and rarity. Recategorization of original satellite image classification into such new conservation value categories is challenging because of the variation in species composition among the new categories. However, it does not represent a major problem for the purposes of early-stage land-use planning. Benefits of interpreted satellite image recategorization as a rapid conservation value assessment tool for land-use planners would be great. 相似文献
994.
The Assessment of Atmospheric Pollution using Satellite Remote Sensing Technology in Large Cities in the Vicinity of Airports 总被引:1,自引:0,他引:1
D. G. Hadjimitsis A. Retalis C. R. I. Clayton 《Water, Air, & Soil Pollution: Focus》2002,2(5-6):631-640
This paper investigates the potential of usingsatellite remotely sensed imagery for assessing atmosphericpollution. A novel approach, which comprised radiativetransfer calculations and pseudo-invariant targets fordetermining aerosol optical thickness has been developed.The key parameter for assessing atmospheric pollution inphotochemical air pollution studies is the aerosol opticalthickness. The need for identifying suitable pseudo-invariantobjects in satellite images of urban areas is of great interest for increasing the potential of earthobservation for monitoring air pollution in such areas. Theidentification of large water bodies and concrete apronsthat can serve as suitable dark and bright targetsrespectively in different geographical areas wasdemonstrated in this study. This study added evidence onthe correlation found between the visibility valuesmeasured at Heathrow Airport area during satellite overpassand aerosol optical thickness derived from Landsat-5 TMband 1 images. 相似文献
995.
极轨气象卫星遥感资料用于陕西洪涝灾害监测 总被引:1,自引:0,他引:1
介绍了利用极轨气象卫星遥感监测洪涝灾害的原理、监测方法和资料处理流程,以及对1996年初黄河陕西段凌汛的成功动态监测的实例。 相似文献
996.
997.
Environmental Management - The objective of this study was to examine the role that watershed urbanization has played in changes to the vegetation types within Los Peñasquitos Lagoon, San... 相似文献
998.
Decision Support System for Managing Oil Spill Events 总被引:3,自引:0,他引:3
The Mediterranean environment is exposed to various hazards, including oil spills, forest fires, and floods, making the development of a decision support system (DSS) for emergency management an objective of utmost importance. The present work presents a complete DSS for managing marine pollution events caused by oil spills. The system provides all the necessary tools for early detection of oil-spills from satellite images, monitoring of their evolution, estimation of the accident consequences and provision of support to responsible Public Authorities during clean-up operations. The heart of the system is an image processing–geographic information system and other assistant individual software tools that perform oil spill evolution simulation and all other necessary numerical calculations as well as cartographic and reporting tasks related to a specific management of the oil spill event. The cartographic information is derived from the extant general maps representing detailed information concerning several regional environmental and land-cover characteristics as well as financial activities of the application area. Early notification of the authorities with up-to-date accurate information on the position and evolution of the oil spill, combined with the detailed coastal maps, is of paramount importance for emergency assessment and effective clean-up operations that would prevent environmental hazard. An application was developed for the Region of Crete, an area particularly vulnerable to oil spills due to its location, ecological characteristics, and local economic activities. 相似文献
999.
Remotely sensed data have been used extensively for environmental monitoring and modeling at a number of spatial scales; however,
a limited range of satellite imaging systems often constrained the scales of these analyses. A wider variety of data sets
is now available, allowing image data to be selected to match the scale of environmental structure(s) or process(es) being
examined. A framework is presented for use by environmental scientists and managers, enabling their spatial data collection
needs to be linked to a suitable form of remotely sensed data. A six-step approach is used, combining image spatial analysis
and scaling tools, within the context of hierarchy theory. The main steps involved are: (1) identification of information
requirements for the monitoring or management problem; (2) development of ideal image dimensions (scene model), (3) exploratory
analysis of existing remotely sensed data using scaling techniques, (4) selection and evaluation of suitable remotely sensed
data based on the scene model, (5) selection of suitable spatial analytic techniques to meet information requirements, and
(6) cost–benefit analysis. Results from a case study show that the framework provided an objective mechanism to identify relevant
aspects of the monitoring problem and environmental characteristics for selecting remotely sensed data and analysis techniques. 相似文献
1000.
我国洪涝灾害加剧的主要因素与进一步抗洪减灾应取的对策 总被引:12,自引:2,他引:10
我国正面临着洪涝灾害加剧的严峻形势。90年代以来,已出现了4个洪涝重灾年,每年的直接经济损失都接近或超过千亿元人民币。本文分析了导致我国洪涝灾害加剧的主要原因:首先是随着人口膨胀,大规模砍伐森林,大面积垦殖坡地,导致水土流失面积扩大,大量泥沙注入江河湖库;加之过度围垦湖泊与沿河低洼地,湖面大幅度萎缩;快速发展的城市化也使出现洪涝的可能性加大,损失加重。在总结我国抗洪防灾经验的基础上,讨论了应该进一步采取的措施,并提出了建立以Radarsat为主体的多卫星抗洪减灾遥感信息系统的设想。 相似文献