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Land use and land cover classification over a large area in Iran based on single date analysis of satellite imagery 总被引：3，自引：0，他引：3
Hossein Saadat Jan AdamowskiRobert Bonnell Forood SharifiMohammad Namdar Sasan Ale-Ebrahim 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(5):608-619
Accelerated soil erosion, high sediment yields, floods and debris flow are serious problems in many areas of Iran, and in particular in the Golestan dam watershed, which is the area that was investigated in this study. Accurate land use and land cover (LULC) maps can be effective tools to help soil erosion control efforts. The principal objective of this research was to propose a new protocol for LULC classification for large areas based on readily available ancillary information and analysis of three single date Landsat ETM+ images, and to demonstrate that successful mapping depends on more than just analysis of reflectance values. In this research, it was found that incorporating climatic and topographic conditions helped delineate what was otherwise overlapping information. This study determined that a late summer Landsat ETM+ image yields the best results with an overall accuracy of 95%, while a spring image yields the poorest accuracy (82%). A summer image yields an intermediate accuracy of 92%. In future studies where funding is limited to obtaining one image, late summer images would be most suitable for LULC mapping. The analysis as presented in this paper could also be done with satellite images taken at different times of the season. It may be, particularly for other climatic zones, that there is a better time of season for image acquisition that would present more information. 相似文献
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An exploratory study on the use of enzyme activities as sediment tracers: biochemical fingerprints? 总被引：1，自引：0，他引：1
Kazem NOSRATI Gerard GOVERS Hassan AHMADI Forood SHARIFI Mohammad Ali AMOOZEGAR Roel MERCKX Matthias VANMAERCKE 《国际泥沙研究》2011,26(2):136-151
Little information exists on the potential of soil enzyme activities,which are sensitive to soil properties and management,for the characterization of sediment sources at the catchment scale.The objective of this study is to explore and evaluate enzyme activity as tracer for sediment fingerprinting in the Hiv catchment(55 km~2),Iran.Therefore,four enzymes were measured from 42 different sampling sites,covering three sediment source areas(rangeland/surface erosion,orchard/surface erosion,and streambank erosion),as well as from 12 sediment samples from reservoir check dams (sediment sinks).The results indicate that,based upon backward mode discriminant analysis,βglucosidase and dehydrogenase,allowed more than 95%of the samples to be correctly assigned to their source areas.These enzymes were selected as input data for a mixing-model to determine the relative contribution of the sampled sediment sources.The mean contributions from rangeland, orchard and streambank sources in the study area were estimated as 11.3%,15.1%and 73.7%, respectively.Using geochemical tracers,the mean contribution from rangeland,orchard and streambank sources was estimated as 14.1%,9.5%and 74.8%,respectively.Combined biochemical and geochemical tracers,similar values were obtained(18.7%,10.7%and 70.7%,respectively).Our results indicate that soil enzyme activity allows for a good characterization of sediment sources,and can provide a complementary tool to currently existing sediment fingerprinting approaches.However, the method should be also tested in other regions. 相似文献
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Hossein Saadat Robert Bonnell Forood Sharifi Guy Mehuys Mohammad Namdar Sasan Ale-Ebrahim 《Geomorphology》2008,100(3-4):453-464
The Iranian Soil and Water Research Institute has been involved in mapping the soils of Iran and classifying landforms for the last 60 years. However, the accuracy of traditional landform maps is very low (about 55%). To date, aerial photographs and topographic maps have been used for landform classification studies. The principal objective of this research is to propose a quantitative approach for landform classification based on a 10-m resolution digital elevation model (DEM) and some use of an Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image. In order to extract and identify the various landforms, slope, elevation range, and stream network pattern were used as basic identifying parameters. These are extractable from a DEM. Further, ASTER images were required to identify the general outline shape of a landform type and the presence or absence of gravel. This study encompassed a relatively large watershed of 451 183 ha with a total elevation difference of 2445 m and a variety of landforms from flat River Alluvial Plains to steep mountains. Classification accuracy ranged from 91.8 to 99.6% with an average of 96.7% based upon extensive ground-truthing. Since similar digital and ASTER image information is available for Iran, an accurate landform map can now be produced for the whole country. The main advantages of this approach are accuracy, lower demands on time and funds for field work and ready availability of required data for many regions of the world. 相似文献
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ForoodAZARIDEHKORDI NobukazuNAKAGOSHI 《中国地理科学(英文版)》2004,14(4):350-354
Japan ranks fifth in the world for the number of large dams. Environmental impacts of large dams are known, such as enormous losses of water or disruption of fish spawning, however, impacts of the dams on their up streams are functions of topography of the up stream. Haizuka Dam is located in Hiroshima Prefecture, Japan and its implementation will start in 2006. This large dam influences its up stream through dam making activities, which occurs in order and with different spatial presences that were categorized into chronological and spatial impacts. In this case study, spatial impacts were further divided into horizontal and vertical ones. The horizontal impacts were identified as new roads, diversion tunnel, dam lake, and submerged cultivated land, while vertical impacts were recognized as submerged historical monuments, slope protections, dam body, and deforested area in the reservoir. There were convergences of spatial and temporal impacts, however, the extent of the impacts was limited to the lake boundary. 相似文献
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In August 2001, the worst flash flooding event of the Caspian Sea regions in over two centuries claimed over 300 lives after
a weekend of heavy rainfall and brought about a devastating disaster in the Mother-Soo catchment, province of Golestan, Iran.
As a result of this event, a series of site investigation were carried out to identify the pertinent factors that led to a
flood of this magnitude. This paper identifies the fundamental causes of the frequent floods and debris flow occurrence in
the area prone to flooding and analyzes the main runoff mechanism of these events. The maximum observed 24-h rainfall depths
and maximum peak discharges at the existing gauges were compared with the depths of rainfall and the peak values corresponding
to the August 2001 flood respectively. For the majority of the rain gauges, the rainfall depth exceeded those of historical
recorded events. In Golestan dam, an increase of 7.5 times the maximum value observed in the past 20 years was noted. The
flood height was 10–15 m while passing through the middle subcatchment area of Golestan National Park. The preliminary evaluation
indicates the existence of bare soil in the catchment, movable material, steep slopes, high rainfall intensity, deterioration
of pasture and forest land, and inappropriate agriculture and development practices as well as climate change were the main
factors for the occurrence and the extent of the August 2001 disaster. Finally, due to the likelihood of flooding and debris
flow events in future, some countermeasures are proposed. 相似文献
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ForoodAZARIDEHKORDI MajidFMAKHDOUM NobukazuNAKAGOSHI 《中国地理科学(英文版)》2003,13(4):328-333
The major concern of this article is to address the shortcoming and outgoing effects of the human activities on the landscape patterns and their consequences in the Sefidrood River watershed in Iran. A flow of data includes three inputs; each of them belongs to one part of three zones of a fluvial system. The three parts of the Sefidrood River fluvial system include Zone 1, a sub-watershed as degradation modeling site, Zone 2, Sefidrood Dam asdam site, and Zone 3, 17kin away from the Sefidrood River path to the Caspian Sea as ending point site. The degra-dation model in the Zone 1 provides a suitable mean for decision support system to decrease the human impacts oneach small district. The maximum number for degradation coefficient belongs to the small district with the highest physiographic density, relatively cumulative activities, and a lower figure for the habitat vulnerability. The human degradation impact were not limited to the upstream. The investigation to the Sefidrood Dam and ending point of the Sefidrood River depicts that sedimentation continues as a significant visual impact in the Sefidrood Dam reservoir and the estuary. 相似文献
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