Geomorphology
Somayeh Khaleghi; Shahram Roostayee; Ali Mohammad Khorshiddoost; Mohammad Hossein Rezaee Moghaddam; Mhammad ali Ghorbani
Abstract
Catchments and river systems altered in response to changes of internal and external factors. Hence, several techniques have been proposed to simulate these changes and Evolution of the river systems. Cellular Automaton is one of the newest river cellular models that define the catchment landscape with ...
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Catchments and river systems altered in response to changes of internal and external factors. Hence, several techniques have been proposed to simulate these changes and Evolution of the river systems. Cellular Automaton is one of the newest river cellular models that define the catchment landscape with a grid of cells, and development of this landscape is determined by the interactions between cells (for example fluxes of water and sediment) using rules based on simplifications of the governing physics.This method is used for simulation of Lighvan catchment with 20 m cell size and 10 years precipitation data (1380 to 89). Simulation results evaluated in two qualitative and quantitative methods, So that the relative changes in the catchment and spatial distribution of erosion and aggradation value in the entire catchment and each cell was identified on Digital Elevation Model map and also, values of different particle size distribution in different discharges showed that with the increasing discharge, and amounts of sediment increased and among this coarse sand have the highest value and very fine sand, clay and silt particles have the lowest value. Also investigation of longitudinal and latitude profile show that Lighvan river is in mature stage and Lighvan channel has been underwent aggradation due to climate changes and increasing catchment precipitation in last decade that causes hillslope erosion and channel aggradation. Finally, Since certainty of Cellular Automata results is difficult and CAESAR is sensitive to input parameters but comparing the results with previous investigation and field observation shows that Cellular Automata has acceptable results.
Climatology
mohammad ali goorbani; surur poorbabak; hosein Jabari; esmaeil asadi; mohammad hasan fazelifard
Abstract
Abstract Classification of Meteorological stations, causing a large volume of data to be allocated a smaller homogeneous groups, Ease of use in modeling and also can help to spread the information to point to the lack of regional data to Statistics regional statistic. Meteorological stations in ...
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Abstract Classification of Meteorological stations, causing a large volume of data to be allocated a smaller homogeneous groups, Ease of use in modeling and also can help to spread the information to point to the lack of regional data to Statistics regional statistic. Meteorological stations in the region has a crucial role in the management and effective use of information. In this study, 112 stations were analyzed in order to classify regions with fuzzy cluster analysis and Kohonen artificial neural Networks. Four parameters, namely mean annual temperature, longitude, latitude and elevation are considered as the classification criteria for grouping to obtain the optimal number of groups the lowest value of Davies- Bouldin index were used. Demarton climatic zonation was performed to evaluate the spatial distribution of clusters obtained from various methods. The results showed that the fuzzy clustering technique with the Demarton climatic zones is more consistent.
Climatology
nahideh Jahedi; mohammadali Ghorbani
Volume 19, Issue 52 , June 2015, , Pages 63-63
Abstract
Being aware of decreasing or increasing trend of precipitation and discharge in watersheds has very important role in water resources management and the subjects relating to water engineering. In this study, the trend of precipitation and discharge at Qara-su River Basin in Ardebil has been studied in ...
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Being aware of decreasing or increasing trend of precipitation and discharge in watersheds has very important role in water resources management and the subjects relating to water engineering. In this study, the trend of precipitation and discharge at Qara-su River Basin in Ardebil has been studied in monthly, seasonal and annual timescales over the period from 1351 to 1382. For investigation of the existence or absence of a trend, Mann-Kendall test was used by detecting effects of all auto correlations coefficients, and Sen’s estimator was used at different significant level to evaluate the magnitude of the test. The results of the calculated values for precipitation and discharge data set indicated that the trend of the Qara-su River discharge was decreasing for both stations in annual timescale. Also, decreasing trend of discharge dataset was found for seasonal timescale in spring, autumn and winter in which significant trend belonged to winter season. Maximum value of decrease for discharge is for Doustbiglo station in spring (-0.62 m^3/s), and the minimum value of decrease for discharge in summer for this station, too. Furthermore, there was not significant trend for precipitation dataset in monthly, seasonal, and annual timescales.
