Showing 5 results for ahmadabadi
Dr Mitra Saberi, Dr Amir Karam, Parviz Zeaiean, Ali Ahmadabadi,
Volume 0, Issue 0 (3-1921)
Abstract
many geomorphic landforms have fractal structures and their formation and transformation can be explained by mathematical relations. The purpose of this study is to identify and analyze the fractal behavior of landforms of macro geomorphologic regions of Iran,as well as studying and analyzing topographic and landform characteristics based on fractal relationships, and also, analyzing the characteristics of dominant geomorphologic processes based on the theory of fractals. In this study, the contour lines of different landforms of Iran (according to the territorial types) including mountains,hills, plateaus, Plain Domains, Fan Breakout, fan alluvial, for pixel sizes of 30,90,200 m, were drawn and their fractal dimension was estimated by using the box-counting method. The morphometric characteristics of the landforms and their fractal dimensions with indexes (max, mean and standard deviation) related to the five variables (height, gradient, profile curvature and planar curvature of the metric) were analyzed by Arc GIS software at each layer.After investigating their correlation with the fractal dimension, the regression analysis was performed binary and the relationship between the fractal dimension,topography, landforms and processes was analyzed. The fractal dimension has the highest correlation coefficient with the gradient and the standard deviation indices, and the lowest coefficient with the profile curvature and the mean index Moreover, for larger pixel sizes, the correlation coefficient decreases between the indices and the fractal dimension.This research can provide a ground for further research on fractal geometry in geography, geomorphology, geology, environment and other Earth sciences.
Ali Ahmadabadi, Zahra Sedighifar,
Volume 18, Issue 51 (6-2018)
Abstract
Climate change is one of the most important challenges that has affected various parts of human life on Earth. In the present study, in order to investigate the climate change, three synoptic stations of Karaj, Mehrabad and Dashan Tepeh with the help of the statistical statistic downscaling model (SDSM) model were used to predict the statistical period of 2016-2045. Finally, the effects of climate change on the hydrologic conditions of the basin with the help of the model (SWAT) was simulated by the Soil and Water Assessment Tool. The amount of surface runoff and runoff at the study area is 10.59 mm in the studied observation period, but this rate was estimated to be 21.27 mm for the predicted period due to the increase of urbanization and changes in utilization. The results of the research, while highlighting the importance of the effects of climate change, are necessary for their application in applying proper management to adapt to climate change in the future policies of the basin management.
Amir Safari, Ali Ahmadabadi, Zahra Sedighifar,
Volume 20, Issue 57 (6-2020)
Abstract
Flood plains and adjacent rivers, which, due to their particular circumstances, are considered suitable places for carrying out economic and social activities, are always subject to the dangers of flood events. Hence, in these areas, determination of flood progression and its elevation relative to the surface of the earth, as well as determining the characteristics of the flood during the various return periods, which will be called flood zoning, will be of great importance. In this regard, this research aims at integrating the WMS hydrologic model with ARC GIS software to estimate flood zones in the Damand, Goladdareh, Saadabad and Maghsoud Baik watersheds on the main river of Darband. At first, the river Darband was divided into 19 main sections and in the HEC-RAS model, the river was zoned. In this research, using different digital maps, the flood extent in the riverside lands was calculated for a flood with a return period of 2 to 500 years. The SCS method was also used to increase the accuracy and reliability and also to identify areas susceptible to runoff production. The results of the study show that, due to land use changes, especially in the river basin and the abundant construction of the studied basin, there is no flood control power.
Mrs Negar Mirzaii, Dr Ali Ahmadabadi, Dr Seyed Morovat Eftekhari, Mrs Elaheh Lofti,
Volume 24, Issue 75 (12-2024)
Abstract
Rivers are always vital arteries of the earth and naturally, they have a gradual and continuous development process which has undergone fundamental changes after the expansion of human settlements and urban development and they have lost some of their natural functions. Wardvard River is no exception to this. This river flows in the west of Tehran province and has been heavily affected by urban development which has undergone continuous changes in its flow path due to human interference and considering that this river flows in the access route of western cities of Tehran province, its natural and gradual evolution has been disrupted that this transformation, it has removed the river from its natural condition. In this research, the factors affecting the geomorphological quality of Wardvard River have been identified and using MQI index, it had evaluated the quality of river morphology. In this method, Wardvard River is divided into 9 study periods and the three main components of the quality of geomorphological performance, artificial structures and channel adjustment have been evaluated in the form of 28 indicators. Results show due to the urban development of Tehran and many artificial changes in the Wardvard river channel, intervals 1, 3, 4, 6, 7 have earned a score of 0.2 due to human interference and canalization of the river and it is very poorly placed on the floor.Intervals 2 and 5 have earned 0.3 points and it is placed in the weak class and intervals 8 and 9 have scored 0.6 due to the low human interference and the natural course of the river and it is placed in the middle class in terms of morphological quality.
Miss Rana Norouzi, Mr Sayyd Morovat Eftekhari, Mr Ali Ahmadabadi, Miss Khadijeh Alinoori,
Volume 25, Issue 78 (9-2025)
Abstract
In recent decades, land subsidence has emerged as a geomorphological hazard and one of the environmental crises, causing irreparable damage to Iran's plains annually, with the most significant current cause being the water crisis. The Eshtehard plain, as one of the industrial and agricultural hubs of Alborz Province, is of great importance and has been declared a critical prohibited zone by the Ministry of Energy due to the sharp decline in groundwater levels. Therefore, assessing the rate of subsidence and addressing the causes and influencing factors for its risk management is of great importance.
In this study, the Differential Radar Interferometry (D-InSAR) technique was used to examine the subsidence of the Eshtehard plain, utilizing data from the Sentinel-1A satellite over the time period of 2017–2023. During this period, the region's subsidence ranged between -2.08 cm and -2.93 cm, with the highest subsidence occurring between 2019 and 2020, approximately -2.93 cm, and the lowest between 2022 and 2023, about -2.08 cm. The rate of subsidence increases from east to west and in the southern expanse. In fact, the maximum subsidence in all study periods is concentrated in the Eshtehard aquifer area, which contains a large portion of farms and villages, the city of Eshtehard, industrial towns (Kosar, Omid, and Eshtehard), agricultural lands, and the highest concentration of underground resources (wells). The results of hydrographs and interpolation using data from piezometric wells also show a drop in groundwater levels and an increase in depth in this area. At the same time, the results of examining the correlation between land subsidence and groundwater depth changes were significant at the 95% level, indicating that as groundwater depth increases, subsidence in the region also increases. Based on subsidence change profiles, the subsidence pattern in the study area is complex. These temporal and spatial variations indicate various influences, including human activities (such as the intensity and type of activity or excessive extraction of water from underground resources), environmental factors, geological characteristics (sediment composition, aquifer thickness, bedrock position, etc.), the rate of aquifer recharge and discharge, and so on.
