Mahdi Boroughani
Volume 27, Issue 3 , October 2020, , Pages 617-631
Abstract
Sistan watershed has caused severe dust storms in the region in recent years due to the drying up of Lake Hamoon and consecutive droughts. This study aimed to identify and determine the characteristics of dust source areas (land use, lithology, slope, and geomorphology) in the ...
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Sistan watershed has caused severe dust storms in the region in recent years due to the drying up of Lake Hamoon and consecutive droughts. This study aimed to identify and determine the characteristics of dust source areas (land use, lithology, slope, and geomorphology) in the Sistan watershed. To identify the dust source area, MODIS satellite images of dust days for the period 2015 to 2019 were used using dust detection indicators including BTD3132, BTD2931, NDDI, and D. The results of identifying dust source area indicate that a total of 211 dust source areas were identified in the whole region. Of these identified dust source area, 61 are in Iran and 150 in Afghanistan. The results of the distribution of dust collection centers in different uses indicate that dryland agricultural lands with 172 centers, dried lake surfaces, and irrigated agricultural lands with 16 and 12 sources have the highest dust collection sources. From the overlap of the lithology map and dust source, it was obtained that the most dust source area with 111 and 98 sources, respectively, are located in continuous and discontinuous sedimentary formations. The results of the distribution of dust source area in geomorphological units indicate that the erosion plain unit with an area of 35.69 percent, 48 dust source area has the highest collection source. Also, the results of the distribution of dust source area in different slopes show that the highest dust source area is in the slopes of 0 to 2% with 107 sources and the lowest located in more slopes of 32%% with 6 sources.
Mohammad Khosroshahi; Majid Hasani; Shirin Mohammadkhan; Abbas Attarpour; Seyed Aziz Karami; Abolfazl Khalilpour; Ebrahim Farahani; Hamidreza Abbasi
Volume 10, Issue 4 , August 2019, , Pages 409-428
Mohammad Khosroshahi; Morteza Abtahi; Mohammadtaghi Kashki; Sakine Lotfinasab; Fateme dargahian; Zohre Ebrahimi
Volume 24, Issue 2 , July 2017, , Pages 404-417
Abstract
So far, different statistics have been presented for the area of deserts in the world and Iran by individuals and organizations. The reason for this difference is mainly due to the disagreement among experts in providing a comprehensive definition of desert and factors affecting its formation. In this ...
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So far, different statistics have been presented for the area of deserts in the world and Iran by individuals and organizations. The reason for this difference is mainly due to the disagreement among experts in providing a comprehensive definition of desert and factors affecting its formation. In this paper, the factors of natural environment, such as climate, vegetation, geomorphology, soil, geology and hydrology, whose effects are directly or indirectly involved in the emergence and general appearance of the desert, were investigated. Therefore, to identify and define the desert ranges in terms of the study factors, a number of indicators were defined, based on which desert zones were identified for each factor individually. Then, digital maps were produced by overlaying the layers. Results showed that the largest area of desert regions in Iran with a surface of 693690 and 567711 square kilometers is influenced by climatic and vegetation factors, respectively, and the least area of desert regions with a surface area of 208041 and 272,258 km is affected by the geological and geomorphologic factors, respectively. From the aspect of soil science, the area of desert regions in Iran covers a surface of 514930 km2. The total area of deserts was calculated to be 9007293 square kilometers, which accounts for 55 percent of the total area of Iran.
ali Nazari; asghar tavakoli; hoda ghasemieh; naser mashhadi; mohammadreza rahdari
Volume 24, Issue 1 , May 2017, , Pages 67-79
Abstract
Wind erosion is one of the most important natural processes in arid and semi-arid areas, occurring as a result of erosive winds. Wind speed, frequency and duration should be considered in studies related to wind erosion. Kashan Erg is one of the most important sand dunes complexes in Iran. To study the ...
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Wind erosion is one of the most important natural processes in arid and semi-arid areas, occurring as a result of erosive winds. Wind speed, frequency and duration should be considered in studies related to wind erosion. Kashan Erg is one of the most important sand dunes complexes in Iran. To study the relationship between the wind characteristics (Uni- directional index, windness index, wind duration and frequency) with Erg morphology and also study the changes of sand flow rate in various regions, anemometers data were obtained from synoptic stations of Kashan, Ardestan, Jangalbani Badrod, Garmsar and Qom. Then, the interpolation map of sand transport and interpolation map of average and maximum wind in Kashan Erg were drawn using GIS software. Finally, the analysis results showed that the interpolation map of sand transport corroborated the results obtained from interpolation map of average wind, because sand transport rate and average wind speed were reduced from east to west of the Erg. Therefore, it is found that wind frequency and duration have more important role in the sand transport and morphology of the study area as compared with the wind speed. In addition, the comparison of Erg morphology and anemometer results in different stations showed that the spring and summer winds had the highest role in the Erg morphology.
Mohammad Gholampoor; Mohammad Khosroshahi; Jalal Barkhordari
Volume 15, Issue 4 , January 2009, , Pages 485-492
Abstract
Desert in terms of geomorphologic aspects has been defined and classified based on the morphogenesis, litological structures and combination of these two criteria. In this study Hormozgan desert has been classified in terms of geomorphologic features using morphometric method in order to separate the ...
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Desert in terms of geomorphologic aspects has been defined and classified based on the morphogenesis, litological structures and combination of these two criteria. In this study Hormozgan desert has been classified in terms of geomorphologic features using morphometric method in order to separate the desert area from non desert area. The objective of this work was to determine the extent of the natural desert of Hormozgam province using maps of geology, topography and combination of data collected from geomorphologic features of desert in the GIS environment. The geomorphologic features such as pediment plains, flooding beds in the route of water way network, drifted sand, nebkas, playa, saline lands and badlands were diagnosed. In order to be able to map all items in maps showing Hormozgan desert areas, the Satellite images from ETM was used to fined the new land features and also correct the boundary of desert lands. Finally it was found that the geomorphologic desert of Hormozgan covers % 17/2 of the whole area of the province.
Majid Hoseini; Mohammad Khosroshahi; Abbas Atapour; Aziz Karami
Volume 13, Issue 2 , February 2006, , Pages 102-108
Abstract
Characteristics of desert areas are different from viewpoint of various sciences. Surveying the desert descriptions from viewpoint of geology, geomorphology, climatology, land cover and pedology sciences shows diversity of desert characteristics. Each one of the mentioned sciences has introduced special ...
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Characteristics of desert areas are different from viewpoint of various sciences. Surveying the desert descriptions from viewpoint of geology, geomorphology, climatology, land cover and pedology sciences shows diversity of desert characteristics. Each one of the mentioned sciences has introduced special indices to identify desert. Therefore to achieve a common description of desert and to classify them in order to use in natural resources fields is a very necessary matter. In this research, the desert indices have been surveyed and assessed from viewpoint of geology, geomorphology, climatology, pedology and land cover sciences then according to it, the desert characteristics which commonly accepted by scientists and experts of the related science have been determined and the desert plan has been drawn from viewpoint of that science and then, by overlying , geomorphology, climatology, pedology and land cover maps determined Climatic deserts. Therefore consider to effective factors, the province deserts were divided in 3 groups include of geologic deserts resulted from the desert indices of geology and hydrology, climatic deserts resulted from desert characteristics of climate, land cover,pedology and geomorphology. By overlying all of 6 maps, they contribute only one zone that it was named real or hard desert .the desert characteristics of all factors and appropriate to that, the general characteristics of the related desert limits was obtained. According to the obtained results, the geologic, climatic and hard deserts have 2170.21, 6768 and 342.42 km2 area in Tehran province respectively and have allocated to themselves 11.2%, 35% and 1.4% of the total province surface respectively.