maryam omidpour; Romina Sayahnia; Y Rezaei
Abstract
Urban development is an inevitable subject due to the increasing population growth in cities. The city consists of open and living systems and a combination of socio-ecological systems. On the one hand, the hurried process of urban growth resulted in the land use change. Subsequently, this manner will ...
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Urban development is an inevitable subject due to the increasing population growth in cities. The city consists of open and living systems and a combination of socio-ecological systems. On the one hand, the hurried process of urban growth resulted in the land use change. Subsequently, this manner will damage to the structure, yield, and ecological processes in each city. Meanwhile, the use of ecologic knowledge with the landscape and resilience approaches can help to analyze the present situation and discover the optimal solutions. The resilience in the pattern of the natural structure of the ecological networks depends on the extent and intensity of the green spots. This research was carried out to determine the vegetation changes in Hamadan city between1982 to 2015 to achieve the evaluation of the ecological network structure in the urban development process with a resilience approach. In this study, a conceptual framework derived from ecological knowledge, resilience ideas and the use of modern technologies, such as GIS and RS, was designed to determine the bio-sensitive areas caused by the substructure urban changes. Besides, this study was performed to preserve the remaining biological resources in this area and preventing damage to the natural ecosystem of this city. A series of satellite imagery was classified in four categories such as such as open area, built land, communication paths, vegetation. After the above classification, these maps were processed and analyzed by the TerrSet software and three types of landscape metrics including creating, loosening and separating were reviewed to identify the types of land use changes in these years. The results show that the vegetated area decreased from 2820.2 hectares in 1982 to 1304.2 hectares in 2015 and, on the other hand, built lands and communication paths were degraded from 606.4 hectares in 1982 to 4274.2 hectares in 2015. In general, it can be concluded that this level of change shows a high urban development, decreases in plant vegetation, and its discontinuation so that the above changes have reduced the resilience of the city's ecology network. At the end of the study, numerous strategies were also provided for the restoration of the entire damage in the natural ecological network of Hamadan and its development.
, Y Rezaei; , M.J. Valadan Zouj; , M.R Sahebi
Volume 9, Issue 1 , October 2017, , Pages 1-16
Abstract
Mountain Glaciers are pertinent indicators of climate change and their surface velocity changes, are an essential climate variable. In order to retrieve the climatic signature from surface velocity, large scale study of glacier changes is required. Satellite remote sensing is an effective way to derive ...
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Mountain Glaciers are pertinent indicators of climate change and their surface velocity changes, are an essential climate variable. In order to retrieve the climatic signature from surface velocity, large scale study of glacier changes is required. Satellite remote sensing is an effective way to derive mountain glacier surface velocities. In this research, we have conducted a comprehensive assessment of Alam-Chal glacier surface changes (include displacement and velocity), all based on remotely-sensed data. All datasets include aerial photos and satellite images were ortho rectified, normalized and co-registered. By using an aerial photograph collected in 1955 as a baseline and comparing it against a 2003 image collected by the SPOT satellite, the glacier retreat, in direct response to changes in local climate conditions were extracted. Furthermore, we have assessed short-term changes over two-time scales (1988-2003, 2003-2005),using an aerial photo acquired in 1988, a 2003 SPOT image, and a high-resolution Quick Bird image collected over the study area in 2005. We have derived accurate glacier surface velocity vectors (RMSE~2m), based on an FFT-based image cross-correlation technique. Our results point to the capability of the proposed method in accurately retrieving glacier surface changes at a high level of spatial detail, which is important for studies of regional climate change.
