Journal of Applied Research in Geographical Sciences

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Measuring spatial - temporal of Yazd urban form using spatial metrics

saeed zanganeh

Abstract

Urban form can be affected by diverse factors in different times. Socio- economic, political and physical factors are among the main contributors. So, one of the most important challenges of urban planners is measuring and identifying urban development pattern in order to direct and strengthen it to sustainable pattern and right direction. The case study of the present paper is the city of Yazd, a middle-sized city in the center of Iran, and the studied years are 1975, 1987, 2000 and 2010. To achieve the main objective of the paper, measuring Yazd growth and expansion by spatial metrics, it has used remote sensing data and satellite imageries and ArcGIS software. The conclusion revealed that in four periods of study, complexity or irregularity of the urban patch shapes has increased, centrality or average distance of the dispersed parts to the city center has decreased, compactness or the number and area of patches their distance from each other has decreased, porosity or ratio of open space has increased and finally population density of city has decreased in a large amount. Therefore, all perimeters show that the temporal - spatial form of Yazd has moved from compact to sprawl. Due to many undesired impacts of urban sprawl, urban planners and authorities are required to use adherent techniques and policies to control urban sprawl and to direct it toward more sustainable directions.

Analysis of Streamflow Changes under Climate Change Using Rainfall-Runoff Model in the Kor River Basin

parisa sadat ashofteh

Abstract

In this study, the predicted monthly temperature and rainfall data from HadCM3 model (base period, ۱۹۷۲-۲۰۰۱) and next period (۲۰۱۱-۲۰۴۰) under A2emission scenario were used to investigate the impacts of climate change on runoff variations in the Kor river basin. HadCM3 model output was downscaled based on a temporal downscaling approach (Change Factor) and spatial downscaling approach (Proportional) for the basin. The time series of monthly temperature and precipitation were produced in future period. The results showed that temperature and rainfall will increase and decrease in the future period relative to the base period, respectively. Then, the calibrated IHACRES model was used to model rainfall-runoff relationships in the Kor river basin. Then, the downscaled monthly temperature and rainfall time series in next period were employed to rainfall-runoff model and the monthly runoff time series were simulated for period ۲۰۱۱- ۲۰۴۰. The comparison of future period runoff relative to observed period showed that the annual runoff in the basin for period ۲۰۱۱-۲۰۴۰ will decrease about ۹٫۴۳% with respect to base period.

gholamabbas falah ghalhari