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.
morteza abtahi; Mohammad khosroshahi
Volume 22, Issue 3 , November 2015, , Pages 492-504
Morteza Abtahi; Abdollah Seif; Mohammad Khosroshahi
Volume 21, Issue 1 , June 2014, , Pages 1-12
Abstract
Temperature and precipitation are basic constituent components of the climate of a region. For this reason, the assessment of present and future trends of these elements have been considered by different scientists such as natural resources or environmental experts. In this study, Namak lake basin was ...
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Temperature and precipitation are basic constituent components of the climate of a region. For this reason, the assessment of present and future trends of these elements have been considered by different scientists such as natural resources or environmental experts. In this study, Namak lake basin was divided in to six sub-basins and then monthly precipitation and temperature data were collected and reconstructed from 1956 to 2005. Average precipitation, maximum and minimum temperatures of sextuple sub-basins of the lake were calculated using Thiessen method in Arch Map software. In order to evaluate the precipitation trend, Standard Precipitation Index (SPI) was used. The trend of climatic factors (temperature and precipitation) was studied by linear regression and Mann-Kendall test. No significant trend was observed in standardized precipitation of the Namak Lake and in its sub-basins except in the sub-basin of Arak in which the trend of precipitation change was decreasing and significant. According to the study of monthly precipitation, strong droughts have been observed in sub-basins of Arak, Roodshoor and Karaj during the last 50 years. The trends of maximum and minimum temperature change were increasing and significant in most basins. Increasing the temperature of the Namak lake basin may be caused by several factors, including increasing greenhouse gases especially in big cities such as Tehran, Qom, Arak, Kashan, Hamadan, and Qazvin.
Hadi Nazari Pouya; Mohammad Khosroshahi
Volume 20, Issue 4 , March 2014, , Pages 625-633
Mohammad Khosroshahi
Volume 20, Issue 3 , November 2013, , Pages 559-569
Abolghasem Dadrasi Sabzevar; Mohammad Khosroshahi
Volume 17, Issue 1 , September 2010, , Pages 127-148
Abstract
Low quality flood irrigation are used on desert area of KaleShoor river of Sabzevar since 1992. The main objective of this research was to asses changes in soil salinity affected by low quality flood irrigation. To meet this, 51 soil samples were taken and tested in the laboratory for salinity and indicators ...
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Low quality flood irrigation are used on desert area of KaleShoor river of Sabzevar since 1992. The main objective of this research was to asses changes in soil salinity affected by low quality flood irrigation. To meet this, 51 soil samples were taken and tested in the laboratory for salinity and indicators require. soil samples taken from depth of 0-30cm, 30-60cm and 60-90cm at the beginning, middle and end of the cultivated rows of the land. Three soil samples were also prepared from the control area. The results showed that EC and PH values reduced in all samples, compared with control points. In addition, organic materials and sand particles which carried by flood water, improved the soil structure and texture of the study area. This study also showed that flood irrigation has been able to reduce gypsum from range of root zone and transported to lower layers.
Akbar Gandomkar Ghalhary; Mohammad Khosroshahi; Gholam reza Godarzi; Hojat ... ZAhedi pur; Esmaeil Azez abadi
Volume 17, Issue 1 , September 2010, , Pages 149-165
Abstract
Desert is a location in which life of plant and animal is hardly possible. In desert formation, different parameters including: climate, geology, vegetation, pedology, hydrology and geomorphology are special and their interaction to each other plays an important role. For desert area vegetation ...
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Desert is a location in which life of plant and animal is hardly possible. In desert formation, different parameters including: climate, geology, vegetation, pedology, hydrology and geomorphology are special and their interaction to each other plays an important role. For desert area vegetation and their boundaries, detailed investigation on such parameters and their interaction to each other is necessary. In this research, desert area of Markazi province was studied from the view point of vegetation. With determination of desert area boundary and gathering detailed data on such an area, the combating desertification and proper use and planning of desert area is possible. For this reason, first of all, the dominant vegetation types were determined and digitized using GIS with Ilwis academic program software. Then the dominant vegetation types were divided to different groups. The map of desert area and their boundaries were determined with taking into consideration the existing data and information and vegetation types characteristics. The result shows that the total desert vegetation types are 276074 ha with 21 special desert vegetation types and their potential capacity were determined. The result also show that the widest desert vegetation types are Hultemia persica – Scariola orientalis with 77833.8 ha which are distributed in Saveh, Arak, Delijan and Khomain townships and smallest desert vegetation type is Nitraria schoberri with 299.5 ha in marginal salty land of Mayghan playa. Finaly, vegetation map with boundaries of 21 desert vegetation types produced for this study area. ation types
Mohammad Khosroshahi; Mohammad taghi khashki; Tahereh Ensafi Moghaddam
Volume 16, Issue 1 , December 2009, , Pages 96-113
Abstract
Many climatology scientist adopted temperature and precipitation among all climatic parameters to identify desert regions from non-desert areas. There is no one definition of a desert that is accepted by all. The boundaries of a desert change radically depend on the variance in the range of proposed ...
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Many climatology scientist adopted temperature and precipitation among all climatic parameters to identify desert regions from non-desert areas. There is no one definition of a desert that is accepted by all. The boundaries of a desert change radically depend on the variance in the range of proposed criteria definition accepted. Thus this study was carried out to identify the boundaries of a desert territory from non-desert regions using climatic data such as total precipitation, average intensity of daily precipitation, annual average temperature and evaporation together with the coefficient of variance and seasonal concentration. For each climatic factor a digital map was produced for all studied provinces using Geographical Information System (GIS). By overlaying all digitized climatic factors a transitional strip of boundary was recognized and then its accuracy was checked with field data and topographic map. Based on this boundary strip, three zones were recognized as 1- true desert zone located inside the strip of boundary.2- non-desert area, outside of the boundary and 3-Semi-true desert zone located in the boundary strip itself. It was concluded that true or natural desert that known as climatology desert are 700991 km2 or 42.5 % of the Iran map.
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.
Farhad Fakhri; Seyid Moh... Jafari; Mohammad Khosroshahi
Volume 14, Issue 3 , January 2007, , Pages 391-402
Abstract
Since geological formation is very important in the process of desert and desertification, in this article lithology, stratigraphy of the Boushehr province was studied with the help of 1:100000, 1:250000 scale maps of G.S.I and N.I.O.C using GIS methodology. Quaternary formations and most ...
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Since geological formation is very important in the process of desert and desertification, in this article lithology, stratigraphy of the Boushehr province was studied with the help of 1:100000, 1:250000 scale maps of G.S.I and N.I.O.C using GIS methodology. Quaternary formations and most of the evaporatic formations in the province were recognized. Saline and evaporatic formations were introduce as “Primary deserts”. Then with the help through overlaying the drainage network on the basic map of Quaternary formations, the secondary deserts was then recognized this kind of desert possess the evaporative material such as gypsum and salt. Both of these processes (The primary and secondary deserts) have formed Boushehr province deserts. final Results showed that 47% of Boushehr province area is classified as desert including 592041 ha “Primary deserts” and 574579 ha as ‘secondary deserts”. It was concluded that most important geological formation effective in deserts formation in Boushehr province comes from Hormoz series, Gachsaran, Mishan and Aghajari formations.
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.