Methodologies of preparing erosion features map by using RS and GIS   总被引：1，自引：1，他引：0  

Mohammadi Torkashvand Ali  Nikkami  Davood 《国际泥沙研究》2008,23(2):130-137

The erosion features map is one of the basic maps in erosion and sediment studies and watershed management programs. Some methodologies of preparing erosion features map by using RS and GIS were compared in research which took place in the Jajrood sub-basin in north-east Tehran, Iran. In the first phase, four working units＇ maps were prepared by integration a） plant cover, geology and slope b） land use, geology and slope c） land use, rocks sensitivity to erosion and slope and d） land use, rocks sensitivity to erosion and land units＇ layers. In addition to these four working units＇ maps, three more maps were also evaluated in separating erosion features including e） land units f） sensitivity of rocks to erosion and g） image photomorphic units. The efficiency of these seven working units＇ maps was evaluated by 314 control points. For this purpose, by using erosion features of control points regarding field views, surface, rill, gully and channel erosion maps were prepared and compared by crossing them with working units＇ maps. Results showed that method ＂d＂ was better than ＂a＂, ＂b＂ and ＂c＂ in providing soil erosion features regarding economic and executive considerations. The accuracy of methods ＂e＂ and ＂f＂ was 53.0 and 42.9% and their Root Mean Squared Error was more than method ＂g＂ and methods ＂a＂ to ＂d＂. The coefficient of variation was highest for methods ＂e＂ and ＂f＇ and the least for method ＂e＂ and the greatest precision was related to image interpretation.  相似文献   

Metal-organic framework Uio-66 for adsorption of methylene blue dye from aqueous solutions     

A. A. Mohammadi  A. Alinejad  B. Kamarehie  S. Javan  A. Ghaderpoury  M. Ahmadpour  M. Ghaderpoori 《International Journal of Environmental Science and Technology》2017,14(9):1959-1968

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A BEM–FEM approach for analysis of distresses in pavements     

N. Subei  S. K. Saxena  J. Mohammadi 《国际地质力学数值与分析法杂志》1991,15(2):103-119

A combined boundary-element–finite-element method is presented for the analysis of distresses in pavements subjected to mechanical and environmental effects. Owing to the spatial dimensions of the problem, the non-homogeneity and the irregular geometry at the pavement joints, a combination of the two methods proves to offer a more realistic solution technique. The advantage of the finite element method (FEM) is in its capabilities of modelling near-field regions at or around the vicinity of the joint, whereas the boundary element method (BEM) is more suitable to model the far-field region at infinity. The three major distresses affecting the serviceability of the pavement system are the temperature, moisture and the applied mechanical loads. The model analyses the stresses and strains resulting from both mechanical and environmental factors in the analysis of a pavement system. Moreover, the infiltration of water through pavement joints, which causes weakening of the subgrade soil, is also analysed. Secondly the curling of the pavement concrete slab under the mechanical and thermal loads and induced friction may cause separation of the pavement structure from its supporting subgrade. Both are treated and modelled in this study. A detailed analysis of the pavement joint with its load transfer device is also performed for the proper assessment of the separation and further extension of the loss of support in the pavement system.  相似文献   

A dye-tracing test as an aid to studying karst development at an artesian limestone sub-aquifer: Zagros Zone,Iran     

Zargham Mohammadi  Ezzatollah Raeisi  Mohammad Zare 《Environmental Geology》2007,52(3):587-594

A dye-tracing test is employed to study the karst development and flow regime at an artesian limestone sub-aquifer, the Khersan3 Dam site, Zagros Zone, Iran. Tracer breakthrough curves showed an early dominant peak followed by a pronounced tailing effect. The peak concentration was a response to induced pressure during dye injection. The results suggest that the dye was pushed into the small pores and fissures around the injection point during dye injection. Hence, the dye moved out as a result of matrix and fissure diffusive processes and created a long pronounced tailing. The maximum flow velocity in the upper artesian sub-aquifer ranged from 0.97 to 2.9 m/h. However, the mean tracer velocity ranged from 0.19 to 0.51 m/h based on the mean residence tracer time; consequently, the flow regime in the artesian sub-aquifer was determined to be mainly diffusive. The results reveal (1) a low hydraulic gradient from upstream of the dam axis to downstream; consequently, there is no considerable flow; (2) poor karst development and diffuse flow at the tracing test area; (3) a discharge zone at a location downstream of the dam axis which is the main terminal of general flow direction at the dam site.  相似文献   

From Jurassic rifting to Cretaceous subduction in NW Iranian Azerbaijan: geochronological and geochemical signals from granitoids     

Anna?LechmannEmail authorView author&#;s OrcID profile  Jean-Pierre?Burg  Peter?Ulmer  Ali?Mohammadi  Marcel?Guillong  Mohammad?Faridi 《Contributions to Mineralogy and Petrology》2018,173(12):102

Previous interpretations of a Jurassic subduction in Iran were based on trace element classification diagrams for granitoids, but their reliability is questionable, underscored by modern examples of continental break-up zones such as the Baja California. We present new field observations, bulk rock geochemistry, Sr and Nd isotope analyses and U–Pb zircon geochronology to assess the age and tectonic setting of previously undated intermediate to felsic magmatic rocks cropping out in the Precambrian basement of NW Iranian Azerbaijan. The geochronology revealed an uneven distribution in space and time: Late Jurassic (159–154 Ma) intrusions and dikes are alkaline to calc-alkaline. Their melt source is mantle dominated with a distinct continental contribution disclosed by radiogenic isotopes and abundant inherited zircon cores. Mid-Cretaceous (112–96 Ma) plutonic bodies and associated volcanic rocks occur only to the east of the major Siah Cheshmeh–Khoy Fault. They have geochemical signatures typical of a metasomatized mantle. In consistence with the sedimentation history of the area, our new interpretation attributes the Late Jurassic magmatism to thinning of a continental lithosphere in a rift-related setting. Mid-Cretaceous magmatism was produced by oceanic subduction beneath the Central Iran continent. We interpret the 40-Ma age gap between the two magmatic episodes as the time of opening of the oceanic basin witnessed by the Khoy ophiolite in the study area.  相似文献   

Cyclostratigraphy across a Mississippian carbonate ramp in the Esfahan–Sirjan Basin,Iran: implications for the amplitudes and frequencies of sea-level fluctuations along the southern margin of the Paleotethys     

Bayet-Goll  Aram  Esfahani  Fariba Shirezadeh  Daraei  Mehdi  Monaco  Paolo  Sharafi  Mahmoud  Mohammadi  Amir Akbari 《International Journal of Earth Sciences》2018,107(6):2233-2263

International Journal of Earth Sciences - The Tournaisian–Visean carbonate successions of the Esfahan–Sirjan Basin (ESB) from Sanandaj–Sirjan Zone, Iran, have been used to...  相似文献   

A hybrid computational intelligence method for predicting dew point temperature     

Mohsen Amirmojahedi  Kasra Mohammadi  Shahaboddin Shamshirband  Amir Seyed Danesh  Ali Mostafaeipour  Amirrudin Kamsin 《Environmental Earth Sciences》2016,75(5):415

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Database extension for digital soil mapping using artificial neural networks     

Mohsen Bagheri Bodaghabadi  José A. Martínez-Casasnovas  I. Esfandiarpour Borujeni  M. H. Salehi  J. Mohammadi  N. Toomanian 《Arabian Journal of Geosciences》2016,9(18):701

Cost and time are the two most important factors conditioning soil surveys. Since these surveys provide basic information for modelling and management activities, new methods are needed to speed the soil-mapping process with limited input data. In this study, the polypedon concept was used to extend the spatial representation of sampled pedons (point data) in order to train artificial neural networks (ANNs) for digital soil mapping (DSM). The input database contained 97 soil profiles belonging to 7 different soil series and 15 digital elevation model (DEM) attributes. Pedons were represented in raster format as one-cell areas. The corresponding polypedons were then spatially represented by neighbouring raster cells (e.g. 2 × 2, … up to 6 × 6 cells). The primary database contained 97 pedons (97 cells) that were extended up to 3492 cells (in the case of 6 × 6-cell regions). This approach employed test and validation areas to calculate the respective accuracies of data interpolation and extrapolation. The results showed increased accuracies in training and interpolation (test area) but a poor level of accuracy in the extrapolation process (validation area). However, the overall precision of all predictions increased considerably. Using only topographic attributes for extrapolation was not sufficient to obtain an accurate soil map. To improve prediction, other soil-forming factors, such as landforms and/or geology, should also be considered as input data in the ANN. The proposed method could help to improve existing soil maps by using DSM results in areas with limited soil data and to save time and money in soil survey work.  相似文献   

Modeling the effects of controlled drainage at a watershed scale using SWATDRAIN     

Golmar Golmohammadi  Ramesh Rudra  Shiv Prasher  Ali Madani  Pradeep Goel  Kourosh Mohammadi 《Arabian Journal of Geosciences》2016,9(11):582

The recently developed SWATDRAIN model was employed to assess the impact of controlled drainage on the water table dynamics, subsurface drainage, and surface runoff in an agricultural watershed in Ontario, Canada. Controlled drainage was defined with a depth of 1.0 m to restrict flow at the drain outlet to maintain the water table at 0.5 m below the surface level during the winter (November–April) and at 0.6 m during the summer (June–August) months. The effects of the absence, or implementation, of drainage water management were predicted for the 3-year period of 1991–1993. Implementing controlled drainage resulted in a 16 % reduction in the mean annual drain flow, while increasing surface runoff by as much as 71 %. This indicates that overall watershed hydrology could be significantly impacted by the implementation of controlled drainage. This research demonstrates the SWATDRAIN model’s ability to predict the controlled drainage in small agricultural watersheds.  相似文献   

Regional analysis of streamflow drought: a case study in southwestern Iran     

Motalleb Byzedi  Bahram Saghafian  Khosro Mohammadi  Maaroof Siosemarde 《Environmental Earth Sciences》2014,71(6):2955-2972

Droughts are complex natural hazards that, to a varying degree, affect some parts of the world every year. The range of drought impacts is related to drought occurring in different stages of the hydrological cycle and usually different types of droughts such as meteorological, agricultural, hydrological, and socio-economical are the most distinguished types. Hydrological drought includes streamflow and groundwater droughts. In this paper, streamflow drought was analyzed using the method of truncation level (at 70 % level) by daily discharges at 54 stations in southwestern Iran. Frequency analysis was carried out for annual maximum series of drought deficit volume and duration. 35 factors such as physiographic, climatic, geologic and vegetation were studied to carry out the regional analysis. According to conclusions of factor analysis, the six most effective factors include watershed area, the sum rain from December to February, the percentage of area with NDVI <0.1, the percentage of convex area, drainage density and the minimum of watershed elevation, explained 89.2 % of variance. The homogenous regions were determined by cluster analysis and discriminate function analysis. The suitable multivariate regression models were ascertained and evaluated for hydrological drought deficit volume with 2 years return period. The significance level of models was 0.01. The conclusion showed that the watershed area is the most effective factor that has a high correlation with drought deficit volume. Moreover, drought duration was not a suitable index for regional analysis.  相似文献