جستجوی مقالات مرتبط با کلیدواژه « Topography » در نشریات گروه « جغرافیا »

Determining the optimal location for the establishment of border posts is one of the important issues in the planning of the I.R.I. Border Guard Command. Each border post is built in a certain place according to the geographical and military characteristics, so it is important to pay attention to the mission and environmental components in the placement of these posts. Keeping this issue in mind, the purpose of writing the present research is to achieve the optimal location pattern in Mehran border regiment outposts.

The current research was conducted with a qualitative approach and using thematic analysis method. The geographical territory of this research is Mehran border regiment, the statistical scope includes all outposts of the border regiment, which was sampled as a whole. Quantitative data were obtained using statistical tests (frequency, mean and dispersion index of standard deviation) and Friedman test and MAXQDA software were used to analyze the qualitative data and prioritize the obtained components.

The findings show that from the participants' point of view, 35% of the location of units of the Mehran border regiment based on the type of mission and assigned tasks was carried out in a scientific manner and using the experiences of experienced experts, 35% have a review opinion regarding the location of border units, and 30% also do not have an opinion in this regard, considering that a significant percentage of the participants believe that the location of the units of the Mehran Border Regiment needs to be reviewed, therefore, to prevent any possible damage, special attention needs to be paid to this issue by the authorities.

The obtained results showed that the location of the outposts of the border regiments of Mehran follows the two main morphological and topographical indicators, which are the direction, peak, type and shape of the valley in the morphological dimension, and the elevation, lowland, elevation and slope of the land in the topographical dimension have been taken into considerations and finally the relevant indicators for each of the dimensions are presented in a model

Spatial changes in soil properties are significantly influenced by factors affecting soil formation such as topography. Topography can create different properties in the soil by affecting the spatial distribution of effective environmental parameters. Topographic features such as contour, slope direction by affecting soil temperature, evaporation capacity, soil moisture, soil organic matter, precipitation, movement and accumulation of soil solution can affect the biological properties of soil. Respiration of soil microorganisms is one of the most sensitive and important biological properties that can affect soil quality. To study the impact of land use change on soil ecosystem performance due to human activities, it is necessary to maintain and restore soil capacity to provide ecosystem services. The aim of this study was to investigate the effect of slope and height classes on soil microbial respiration in agricultural, rangeland and forest areas of Khanghah Namin village.

In order to conduct this research, in the fall, samples of intact and untouched soil from the study area were prepared in 72 points by regular networking method with distances of about 200 meters. Common physical and chemical properties of soil including soil pH, electrical conductivity, equivalent total calcium carbonate, organic matter, soil texture (percentage of sand, silt and clay particles) and total porosity were measured. From soil biomarkers, basal microbial respiration and substrate-stimulated respiration were determined. Kriging geo statistical method was used to estimate and determine the spatial distribution and evaluate some soil properties as well as cumulative soil quality indicators. For this purpose, the geographical coordinates of each point of the GPS device were transferred to GIS software. After recording the data of the sampled points, the interpolation command was executed and the information of the non-sampled points was obtained. In order to explain the spatial similarity of the variables, the experimental variogram of the data was obtained using GS + statistical software and the best variogram model was selected according to the variogram information. Finally, the distribution map of soil biological indicators was extracted using GIS and Kriging geo statistical methods. The correlation between the measured and estimated values of soil biological properties was calculated and evaluated in SPSS19 statistical software. Experimental factors included three land uses (namely, agriculture, rangeland and forest), slope direction at two levels (north and south) and two elevations (<1580 <) in terms of significant mean difference in field moisture. Normalization of data was performed by Shapiro-Wilk (1965) test using SPSS19 software. Mean comparison was performed unpaired by T-Test using SPSS19 statistical software. Pearson correlation between soil microbial base respiration and substrate-stimulated respiration with other soil properties was obtained in SPSS19 software.

The results of the descriptive statistics of the soil properties showed that most of the soils in the study area have a loam soil texture class. The pH value of the samples was in the range of 5.7.7, the percentage of organic carbon was 0.6.6 % and calcium carbonate value was from 0.67 % to 16.67 %. The maximum electrical conductivity (EC) was less than 2 ds/m of Siemens per meter, indicating the non-saline soils of the area. Also, the high levels of average microbial base respiratory and the substrate induced respiration were 1.21 and 7.5, respectively. High correlation between the properties of soil organic carbon percentage, porosity percentage, silt percentage, farm moisture percentage and soil pH with base microbial respiration and substrate induced respiration with clay, sand and electrical conductivity of the soil were not significant. The farm moisture had the highest hydraulic soil with the lowest correlation with microbial respiration. In general, the average base and substrate induced respiration was higher on the height contour (1580<). Also, both base and substrate induced respiration in accordance with elevation had a significant mean difference at 5 %. In the present study, the studied slope on the north and southern slopes on the base microbial respiration level at 5 % probability level and substrate induced respiration with the probability level of 1 % was significantly different. The highest amount of these indicators was measured on the northern slope of the area and the lowest in the south slope of the southern south slope located mostly in the center to the northeast of the area and the northern slopes in the southern and northern parts of the area. It is maintained that the cause can be attributed to the existence of heights and solar radiation on the southern slopes. To determine the distribution of soil biological indexes at the level of the study area, the distribution of the area's biological properties of the area was prepared by applying the Kriging method. The best model for drawing soil base respiration map was selected for substrate induced respiration with the largest soil bed based on the highest R2, the range of impact, the least RSS and the effect of the piece. The largest amount of soil respiration was observed by the base respiration and irritated respiration in the north and northeast of the area. It is also observed that as the height of the area increases from west to east, basic respiration is generally stimulated with a relatively increased trend. The results show that there is a significant correction in both characteristics of measured and estimated values ​​by the Kriging internalization method.

In this study, the amount of basal and bed-stimulated respiration in forest lands was significantly higher than rangeland and agricultural lands. Between rangeland and agricultural uses, the amount of soil microbial respiration in agricultural lands was lower. Due to the fact that this area is a tourist destination and there are local livestock, this finding can be attributed to transportation, high human and livestock activity at lower altitudes, and agricultural and pasture use, which are more exposed to these activities. The microbial respiration values ​​in the northern direction of the slope were significantly higher than in the southern direction. The southern slopes received more solar energy than the northern slopes. Usually in the south-facing slopes, the number and activity of soil microbial community is low due to high temperature, low water, low porosity and adverse consequences due to inadequate vegetation. In addition, a significant mean difference was observed in the northern and southern directions of the slope. Also, the increase in altitude due to the relative increase in humidity and decrease in temperature led to an increase in microbial respiration. This issue can significantly affect the activity and respiration of soil microorganisms by affecting soil processes and its development as well as the amount of vegetation in the two slopes. According to the obtained results, it can be stated that the evaluation of biological properties that was discussed can play a prominent role in controlling the management factors in the area. Large changes in soil respiration indices are probably due to the high sensitivity of these properties to human factors such as tillage operations and the use of chemical fertilizers, which cause changes in soil surface uniformity. The zoning map of these two features also confirmed this. The results showed a logical correlation between soil microbial respiration and other characteristics that the existence of a correlation between soil properties indicates a strong relationship between them. Geo-statistical science in this study was able to estimate the properties well. The results of this study showed that in the studied area, biological indicators depend on the position of the landscape and land use, and these factors can affect the structure, development and evolution of soil by affecting the structure of the microbial community.

Old trees are important and key elements of forest sites and are of great value in terms of forest management, reforestation, silviculture and ecology. Although old trees constitute a small percentage of forest trees, they account for a large share of forest carbon reserve and play a vital role in carbon storage. Understanding the how geographical and site distribution of these trees across the forest is essential to obtain information for forest restoration management. Therefore, this study was carried out to investigate the geographical and site characteristics of old trees of Wing nut, Ash, Hackberry, Sycamore, Elm, Olive, Cypress and Fig in Ilam province.

After querying the villagers and local people and conducting numerous forest surveys, the old trees were identified and selected on the basis of the diameter of the breast. Then their geographical characteristics including city, district, village, geographical coordinates and site conditions including slope, aspect, altitude, soil depth, climate and proximity to water source were measured or recorded.

The results showed that in terms of geographically distribution, the identified old trees have located in Ilam, Mehran, Malekshahi, Badreh and Dehloran cities. Topographically, the old trees of Wing nut, Elm, Ash and Fig were located in the 0-10% slope class, Hackberry and sycamore in the 0-10% and 10-30% slope classes, olive in the 10-30% slope class and Cypress in the 40-70% slope class. The old trees of Wing nut, elm, Ash and Hackberry were located in the north aspect, fig, sycamore and Cypress in the south aspect and olive in the west and south aspects. The old trees of Wing nut, elm, Ash, Hackberry, Sycamore and Cypress were dispersed at altitude class of 1100–1250 m and olive and fig old trees were at altitude class of 1250–1400 m above sea level. Climatically, the old trees of Wing nut, elm, Ash and Hackberry were located in the very cold Mediterranean climate, Cypress trees and some sycamore trees in the cold Mediterranean climate, and fig, olive and some plantain trees were in the semiarid cold climate. In terms of access to water resources, old trees of Wing nut, elm, Ash, Sycamore, Hackberry and Fig were located on the bed or margin of river, old Cypress trees had no access to water resources and some olive trees were close to water resources. In terms of soil subsidence, old trees of Wing nut, elm, Hackberry, olive, and fig were mostly in soils with medium depths. Old ash and sycamore trees were present in shallow to medium depths and old cypress trees were present in shallower soils. Although the identified old trees were present in limited sites, their long-term and sustained presence in these sites indicates that sites conditions are favorable for their survival.

Therefore, it can be concluded that the presence of low slopes, suitable soil bed and access to water resources were desirable characteristics for stability and survival of the studied old trees in these sites. Due to the above-mentioned characteristics, ecologically similar sites can be found in the forests of the province and can be restored by seed of old and resistant trees.

Air pollution, as one of the most important environmental hazards in urban areas, is closely related to weather conditions. Today, pollution in metropolitan areas has become an important issue that requires the study and presentation of practical solutions to improve living conditions in this area. Therefore, understanding the relationship between synoptic systems and air pollutants helps a lot in how to solve environmental problems and future planning. Therefore, in this study, compression algorithms of carbon monoxide emission and transfer from domestic and foreign sources were analyzed. For this purpose, GEOS-5 / GMAO / NASA satellite images were used. The results showed that the highest amount of pollution from the seasonal point of view is related to the cold and early morning seasons and the lowest is related to the early afternoon and hot season of the year. And Khuzestan are densely populated carbon monoxide cores. Low pressures of the eastern Mediterranean play an important role in reducing pollutants in the southwest of the country and in the south of the country, under the influence of atmospheric currents from the topographic cut of Bandar Abbas, air streams polluted with carbon monoxide are able to penetrate into the interior to the southern half of Kerman. Increased by low pressure systems in Afghanistan and Pakistan. The Zagros Mountains also play an important role in preventing the entry of pollutants produced by western neighbors into Iran. In summer, Iran is polluted by carbon monoxide carriers by monsoon currents from central and southern Africa to Iran and has caused a lot of pollution

Erosion and sedimentation in watersheds has caused many problems in healthy and sustainable use of water and soil resources, and is considered as one of the major threats to global economic and environmental sustainability. The increase of sediment yield in watersheds has consequences such as dam filling, river diversion, conductivity capacity reduction of waterways and water facilities, and changes water quality for drinking and agriculture. So, spatial modeling and prediction of sediment yield in watersheds is very important, especially in arid and semiarid environments. In this regard, we should consider the whole process of erosion (destruction, transport and deposition), so that the relationship between inputs and outputs of the system are understood well. The Systematic view of geomorphology on the issue of erosion and sediment yield can be very effective and useful, considering the relationship between forms, materials and processes in the context of landform components. Recognizing the different processes of erosion and sediment production in the range of landform components can provide a more comprehensive and practical view of these processes in watersheds. Given the importance of the issue and the need to use digital elevation models in order to model the sediment yield variations, which have been recently considered, this study intends to analyze the relationship between the Landform components distribution and sediment yield in the Qarasu watershed, N.W. Iran. 

We use extensive and integrated statistical analysis of non-parametric (χ2) and parametric (regression) methods to understand the relationships between sediment yield (S.Y) variation (dependent variable) and distribution of components or classes of landforms (independent variable). 19 sub-watersheds, which have sufficient and reliable data of sediment yield (ton/y), were selected for analysis. As catchment area acts as a misleading variable in the  relationships between sediment yield and physiographic variables, a specific sediment yield (S.S.Y) ​​ (ton/km2/y) was used as a dependent variable. Also, an independent variable (landform components) was extracted of digital elevation model (DEM) with a resolution of 30 m. 6 landform classes, including 1- ridge 2- upperslope 3- midslope 4- toeslope 5- flat 6- valley, were delineated in the geographic information system (GIS) environment. Then, the percentage area of the landform classes was calulated as an independent variable. In order to perform the nonparametric test, it was necessary to convert the variables from quantitative to categorical and qualitative form. Classification of S.S.Y was done in 2 categories (low, high) and 3 categories (low, medium, high). Also, the classification (categorization) was done for the independent variable. These transformations and statistical tests were performed in the SPSS environment. The significance level of qualitative and quantitative tests were ≤ 0.05. It should be noted that the classes can be assumed to be both nominal and ordinal, ie low (1), medium (2) and high (3). Therefore, statistics related to the crosstabs can be obtained for both nominal and ordinal scales, indicating the quality and quantity of the relationships. On the other hand, the correlation test can be done in two ways, Pearson and Spearman.

In the first step, results of the non-parametric analysis showed that there are significant relationships between the distribution of S.S.Y classes and the Landform components classes expect 2 landforms: valley and ridge. meanwhile, the importance and certainty of the relationship between midslope and S.S.Y was determined in respect to repetition of significant relations during three χ2 tests. In the next step, the results of Pearson correlation analysis showed the positive correlation between ridge, midslope, valley landforms and S.S.Y. On one hand, and the negative correlation between upperslope, lowerslope and flat ladforms and S.S.Y on the other hand. The highest and lowest correlation coefficients were observed in midslope (R = 0.4) and upperslope (R = -0.03) components, respectively. The Results of the latest test, the Spearman correlation test, were indicative of similarities with the χ2 test, showing the significant relationships between flat, toeslope, midslope landforms and S.S.Y. Although more contribution of the midslope in sub-watersheds area and higher difference among sub-watersheds in terms of midslope contribution influence its relations with S.S.Y,("but" not needed) close and direct relationship between the midslope area and S.S.Y is attributed to high sediment supply and the occurence of dynamic sediment transport within this landform component.

Erosion and sediment yield (S.Y) within watersheds due to their extensive environmental dimensions as well as the complexity of the erosion process (destruction, transpotation and sedimentation) are the focus of systematic approach of geomorphology to provide useful and comprehensive knowledge of the inputs and outputs of the watershed system. Dividing the catchments into landform components and establishing a relationship between their distribution and S.Y of the catchments can be a key solution in this regard. In this research, applying the approach through both parametric (Regression) and non-parametric (Croostabs) statistical analyzes showed that important information about the relationships between landforms and S.Y can be acquireed at synthetic statistical method. Although the relationship between the independent and dependent variables in the qualitative test had superiority to the quantitative test in terms of the significance of the relationship, the type and strength of the relationship was determined by regression analysis. Meanwhile, the existence of a close and definite relationship between miidslope distribution and S.S.Y refred the necsessity for geomorphic prioritization of watershed management and soil protection measures in this landform class. In general, it seems that the classification of variables nominally and ordinally reduces the effects of residuals and makes the relationships of variables more meaningful. Furthermore, the distribution of landform components among the catchments and the existence of homogeneity/heterogeneity in this regard affect the quality and quantity of relationships, which is necessary to pay attention to in regional analysis of S.Y variations.

Destruction and habitat fragmentation are considered as the most challenging issues of biodiversity and establishment of protected areas is one of preventive methods to reduce biodiversity. Therefore, there are different criteria to choose it. Kermanshah province has covered different habitats due to its diverse ecologic condition. The current study aims to evaluate and compare the distribution of effective indices on habitat diversity in protected areas of Kermanshah province. In this regard, Surrogates such as altitude, slope, aspect, roughness  of altitude, Shortwave Infrared Water Stress Index (SIWSI), Compound Topographic Index (CTI), normalized different vegetation index (NDVI), vegetation type and Roughness of NDVI have been used as Biodiversity surrogates. Since the protected areas should be indicative samples of their surroundings, all the mentioned variables were prepared for Kermanshah province area and then all maps for slope and cover type were divided into 10 classes based on Jenks method. Shannon-Wiener (H), Simpson (D) and Macintosh (D) indices were used for diversity analysis, and Pielou (J') and Macintosh (E) indices were used for richness analysis. The results show that in terms of diversity indices for slope, CTI, altitude, NDVI, roughness  of altitude, Roughness of NDVI, SIWSI and slope ,Hashilan no hunting area, Ghalajeh protected area, Nava Koh no hunting area, Dalakhani and Amroleh no hunting area, Bistoon protected area and Bistoon Wildlife Refuge have the highest diversity indices, respectively. The slope and CTI variables share most similarity in terms of distribution of classes among the protected areas, and the vegetation type variable has had the least similarity among the protected areas. Among the hunting-banned and protected areas, the highest diversity exists in the Amroleh and Dalakhani and Bistoon protected area, respectively.The results of this study can be useful in choosing the correct complementary protected logic.

Wildfires cause substantial losses of property and human lives in ecosystems in Iran and all around the world. Every year, about 6000 ha of forests are affected by fires in Iran (Jahdi, Salis, Darvishsefat, Mostafavi, Alcasena, Etemad, Lozano, & Spano, 2015).These fires can occur naturally due to climate change or abnormally caused by human activities in the forests. In fact, fire is one of the most important factors in disrupting the structure and dynamics of forest in natural conditions that produces a large amount of dead wood caused by the destruction of trees (Coban & Mehmet, 2010). As a result, there are significant costs to prevent fire every year in countries it takes place, and managing ecosystems is a way to reduce the effects of fire on war and maintain perspectives. To manage fire in forests, understanding the behavior of the fire and the factors causing it in a prone environment and factors affecting its behavior are essential (Artes, Cencerrado, Cortes, & Margalef, 2013). One way to manage fire is FARSITE model. This model has become popular due to its steady structure and simplicity of popularity in the modeling of fire spreading. This model is considered as one of the main fire simulation systems used to describe the behavior and release of horrific fires and is a semi-experimental model (Shen, Prince, Gallacher, Fletcher, & Fletcher, 2017).

For the FARSITE Fire Extender simulator, we need 5 layers of GIS height, slope, direction, fuel type, and canopy. All of these spatial data describe the landscape of the area. Topographic data (elevation, slope and tilt direction) were extracted from 1: 25000 maps of the country's mapping organization, which were converted to ASCII (Kanga & Singh, 2017) format using ArcGIS10 to prepare for entering the FARSITE model. Meteorological data is another input similar to the FARSITE firewall, which includes the degree of heat, relative humidity, and wind speed. To obtain climatic data, synoptic stations in Ilam province were recorded at 3-hour intervals. The appropriate burning model of the research area was selected based on the description of 53 standard burning model developed on the basis of the fire extension model. This selection was made using vegetation maps, map coverage of the area and observations and field studies based on similarity of the existing vegetation characteristics and description of this model. In the last step, in order to simulate the GIS layers (slope, direction, height, combustion and canopy), the FARSITE model was entered in an appropriate format. Then, the area was classified according to the extent of the fire.

The results showed that fire in four areas where it occurred had different behaviors, which is also due to different natural conditions in these areas. Also, fire hazard zoning, in the province of Ilam shows that, 1.5% of the area has a high risk of fire. Therefore, it can be stated that the study of different factors (topography, vegetation, burning and climatic conditions) in the studied areas shows the complexity of fire behavior in these areas. It is under the control of various factors. To identify the behavior of the fire, all the parameters and influential factors must be considered together and in conjunction with each other.

Also, according to the results of FARSITE simulation and its accuracy evaluation in the region, using kappa coefficient, all points are in agreement with real values, which indicates the performance of the model in this region, and in none of the regions the coefficient value Kappa has not been negative. Therefore, the implementation of this model is a useful guide for forest fire management, and based on it, a fire prevention crisis management program can be implemented in the three phases of initial operations or pre-occurrence measures (prevention plan), action plans (coping plan), and post-operation operations (recovery plan).

Faba bean is one of the main winter crops in Golestan province (northeast Iran), with an estimated production of about 106,284 tons of green pods and 7256 tons of dry grain while the harvesting land area  is about 1838 ha. Topographic characteristics, climatic conditions and the soil quality of an area are the most important parameters to evaluate land suitability. To develop successful cropping systems, it is necessary to understand how a crop such as faba bean responds to biological, chemical, physical, and climatic variables, and how this response can be influenced by management. Accordingly, farmers can improve their production in this district, and at the end of the study, the distribution and areas of land suitable for faba bean cultivation in Aq Qala were determined. In addition, this research provides information at a local level that could be used by farmers to select cropping patterns in accordance with suitability results.

The study areas of the research include agricultural lands and rangelands of Golestan province  Using 1: 50,000 maps of the national cartographic center of Iran, we created a 20 m digital elevation model (DEM) with a topo-to-raster function. In this study, the first agro-ecological requirements of faba bean were determined according to scientific resources. Several parameters were considered in this study, including the annual average, minimum and maximum temperatures, annual precipitation, slope, elevation, and some soil properties such as organic matter, pH, EC, texture, phosphorus, potassium and calcium. The last 12-year climatic data were gathered from 4 meteorological stations and 21 rain gauge stations in the Golestan province. The mean temperatures were calculated from daily mean minimum and maximum temperature data. The rainfall and temperature data of the whole province were used to interpolate and draw map of annual rainfall, and annual average, maximum and minimum temperature by geostatistical and interpolation methods. The slope and elevation information was obtained from the Digital Elevation Model (DEM) using GIS software. The standardization of data was used from fuzzy method and Analytic Hierarchy Process (AHP) was used for weighting the criteria. Finally, using ordered weighted average (OWA) in the  IDRISI software, faba bean cultivation potential map was prepared.

The results indicated that the most important variables, according to their specific weighting, were annual precipitation during the growing season (0.2876), slope (0.5396) and EC (0.3913). The digital environmental layers overlaid and integration in GIS media, then zoning of lands were carried out in 4 classes (highly suitable, suitable, less suitable and non-suitable). The study area includes different classes with diverse capacities for faba been cultivation comprising: a highly suitable potential, which constitutes 55.78% of the total area; a suitable class, 27.82%; a less suitable, 12.23%; and non-suitable, 4.17%. The final maps showed that more than 80% of agricultural lands of township are suitable for faba bean production. This research provides information at a local level that could be used by farmers and decision makers to select cropping patterns in accordance with their suitability. The topography, soil characteristics and climatic conditions were the most important determinant parameters of this evaluation. Our results revealed that 86.60% of the land area is suitable for faba bean cultivation. From the land suitability analysis, it was concluded that, in general, some nutrient contents of the soil are low or high for the study region. In addition, the research results indicated that the main limiting factors are high EC and low rainfall.

In conclusion, a combination of GIS, AHP and OWA is a practical and applicable method for determining land suitability for faba bean crops. In this study, the time-saving during the development of the land suitability map for faba bean was considerable. This method is almost a new application in Iran for land suitability analysis. However, decision makers should consider the side effects of applying these methods in the determination of suitable areas for crop growing. The result in of this study indicated that the OWA is a valuable approach in land suitability assessment, therefore, we suggest that the OWA should be used with AHP in future land suitability evaluation. We recommend that similar studies should use other parameters such as relative humidity, wind speed, solar radiation and heavy soil metals.

Zagros Mountains range as the most important face of topography in western Iran can affect the activity of precipitation systems in addition to the effect of orography on the occurrence of precipitation. The objective of this paper is to analyze the enhancing effect of the Zagros Mountains on the Sudanese system. For this purpose, three one-day rainfall samples including December 2, 1999, March 30, 2012, and March 20, 2015 were selected and analyzed using factor analysis among one-day Sudanese rainfall systems during the period  from 1996 to 2017. The method used was synoptic analysis of atmospheric parameters and rainfall interpolation model in GIS environment. This study demonstrated that the warm air stream and contact of the Sudanese system with the western and southwestern slopes of Zagros reduced the geo-potential height and formatted a positive vorticity field. Positive vorticity blow to the southeast and inland slopes of Zagros caused upward movements on these slopes. At higher levels of atmosphere, cold air blow in adjacent to warm air blow area of lower levels of atmosphere reduced the geo-potential height of the atmosphere and enhanced the upward movement of the atmosphere. Thus, suitable thermodynamic conditions were provided for the growth and reinforcement of convective clouds and heavy rainfall over the topography surface. In this study, it was found that in all the studied rainfall samples, entrance direction of the system and humidity to region has followed from width and length of wave in middle layer of atmosphere. The results showed that the maximum precipitation was observed in the slopes located in direction of Sudanese rainfall system entrance. Also, precipitation changes on steep slopes of Zagros were also greater than other levels.

The soil is one of the most important factors of production that has a great influence on human economic and social life. The surface of the earth is generally covered by soil and other surface deposits. Soil erosion is one of the most important problems and problems we face today. Increasing exploitation and lack of proper human management of the natural environment have a great effect on the intensification of soil degradation and erosion processes. In this research, the effective parameters analysis of erosion and sediment production in Dakehah basin with a total area of 9923.2 ha in southern Kerman province was studied using the Revised Universal Soil Erosion Model (RUSLE). Data and tools used in the research include data from meteorological stations, digital elevation model (DEM), ETM 2015 satellite imagery, GIS and remote sensing (RS) It should be. By studying the effective factors in this model, which includes rainfall erosivity factor, soil erodibility factor, topographic factor, and vegetation, the purpose of this study is to estimate the annual soil erosion in the study area. The erosion rate of the basin is estimated. Accordingly, annual soil erosion in the whole study area is estimated at 67 tons per hectare per year. The results of this study show that the highest effect on the estimation of erosion, a topographic factor with the highest coefficient of explanation was 92.6 In this research, the effectiveness of RUSLE technologies of annual soil erosion is confirmed by the new model of GIS and remote sensing for quantitative estimation of soil erosion values.

Abstract For crop growth and phonological stages of their development requires appropriate environmental conditions of air, water and soil are. This study to evaluate the climate and environment for the province and determine the saffron crops susceptible to these product areas by GIS software is. For this study data from 12 meteorological synoptic stations in the province at a statistical 20-year period (1987-2006) are used. The study by comparison with regression stations province city Torbat Areas of saffron-rich Khuzestan province in Iran similar climate and Torbat of precipitation and temperature were determined and other climatic conditions for the product has been evaluated saffron. This study shows the topography role for plants such as saffron, elevation and slope, northern and eastern province talented and suitable for cultivation of saffron are the product. Khuzestan province away from the northern and northeastern and unfavorable conditions for the cultivation of saffron is faced with constraints.

In the contemporary era, vital environmental resources such as water and soil have degraded resulting from increasing population, development of environmentally harmful activities, inappropriate management and so on. Today, development beyond ecological thresholds and degrading the main factors of development and human survival has turned into one of the major challenges of human society. If this trend continues, the world society will face with various problems such as food security, environmental conservation and preservation of natural heritage. From perspective of land use planning, development of economic activities without taking into account the potentials and the degree of production capacity of land resources can bring about various environmental, social and economic problems in a specific region. Therefore, at any region, especially mountainous areas like Urmia, understanding and appropriate management of land resources and its parameters is necessary and unenviable for land sustainability Considering the physical conditions of land such as topography and landforms in Urmia region, which making sever limitations for development, it seems that analyzing of land characteristics and identifying limitations and potentials of this region can be used as an effective tool for land users in terms of developing activities. The present study is aimed at answering this critical question that: how much topographic and landform conditions can affect on land suitability for developing activities in Urmia County. The result of this study will lead a base map which can make a background for further evaluation of the land for determining various land uses in the region. In order to identify suitable classes for developing activities, the Multi Criteria Method was used. MCE is a method for combining data according to their importance in making a given decision. At a conceptual level, MCE methods involve qualitative or quantitative weighting, scoring or ranking of criteria to reflect their importance to either a single or a multiple set of objectives (Heywood and et al., 2006: 239). Over the last decade or so, a number of multiattribute (or multicriteria) evaluation methods have been implemented in the GIS environment including WLC and its variants, ideal point methods, concordance analysis, and analytic hierarchy process (Malczewski, 2004: 34). Among these procedures, the WLC and Boolean overlay operations are considered the most straightforward and the most often employed (Chen & et al., 2001: 387; Malczewski & Rinner, 2005: 250; Malczewski, 2006: 270; Lafortezza & et al., 2008: 194; Boroushaki & Malczewski, 2008: 399; Jelokhani-Niaraki & Malczewski, 2015: 493). WLC (or simple additive weighting) is based on the concept of a weighted average. The decision maker directly assigns the weights of ‘relative importance’ to each attribute map layer. A total score is then obtained for each alternative by multiplying the importance weight assigned for each attribute by the scaled value given to the alternative on that attribute, and summing the products over all attributes. When the overall scores are calculated for all of the alternatives, the alternative with the highest overall score is chosen (Malczewski, 2004: 34). Operations of overlaying layers 1. Producing Map A In order to produce map A, at first stage, slope and elevation parameters were compared. The Statistics results of this map show that the highly suitable and suitable classes cover 31.66 and 30.31% of the total area, respectively. The results also show that the combination of the slope and elevation layers has placed approximately 40% of the total areas in limited and not suitable classes.
2. Map B In order to produce map B, the standardized layer of aspect is overlaid with map A. The results of the topographic map indicate that only 21 percent of the total area is highly suitable for developing activities. In the second class, i.e. suitable, which cover 22 percent of the total area, the lands are suitable for some activities.
3. Map C By overlaying land type and map B and producing map C, more filtering was applied in structural land layers for developing activities. This phase can be regarded as the milestone of the layers overlaying process. In other words, in this step, by adding land type layer, main characteristics of land combined and the geomorphology map the region was completed. By producing geomorphology map, the area of the highly suitable was decreased, significantly. Therefore, the area of the highly suitable decreased to 13.02 percent, which indicate the highly effeteness of the land type in filtering among natural parameters for developing activities.
Producing Final Land Suitability
In final map, the drainage layer as an effective parameter was used in the analysis. The drainage map generated from river density and line density function. The results of this map show that approximately 11 and 21 percent of the total area is highly suitable and suitable, respectively. By adding drainage layer to geomorphology map, the areas of the two mentioned classes were significantly decreased. According to final land suitability map, 33 percent of the total area is highly suitable and suitable, 28 percent marginally suitable and 38 percent not suitable. The results of parameters overlay showed that in all of the steps topographic elements have significant role in filtering of land suitability for developing activities. The results of the overlaying land evaluation map and slope with proposed land suitability demonstrate that the classes of marginally, very low and not suitable, with slope of 20.18, 28.69 and 42 percent, respectively, have severe natural limitations and the possibility of developing activities is not practical in approximately 67 percent of the total area. Therefore, topographic and landform characteristics of the region are the main constraints in developing of the activities in Urmia County. Based on these results, achieving to any activity development in Urmia requires to prioritize and take into consideration environmental issues and sustainable management of natural resources.

  Geomorphology is de_ned as the science of Earth's diverse physical landforms with an emphasis on their origin and distribution across the landscape as well as the dynamic processes that shape the topographic features . Enhancing the uptake of geomorphic understanding and its underlying processes play a key role in understanding of physical geography, as one of the major research challenges in geography Fractal and multifractal analysis of topography has long been a very useful method to obtain synthetic topography in geology and geography which has led to a variety of di_erent results. The concept of fractals was rst introduced by Mandelbrot [1967] as a measure of the Earth's topography, the length of a rocky coast line [Mandelbrot,1982] The fractal dimension is a measure of global property of the system in question and in many cases is independent of various details and so it is used to classify di_erent systems and models in terms of the value of the fractal dimension besides other statistical measures.
However, in various studies in the past (see e.g., Lovejoy and Schertzer (1990); Lavallee et _ al. (1993)), it has been noti_ed that in some cases the topography is not far than simple to be explained with a single scaling exponent such as the fractal dimension, it is rather more appropriate to study topography as a scale invariant quantity that generally requires multifractal measures and exponent functions. This gives rise to an in_nity of fractal dimensions for di_erent statistical moments of a variable are needed to completely characterize the scaling properties.
There exist a few multifractal studies of topography showing the multiscale properties of the height pro_le over various ranges in length scale (see for example Lovejoy and Schertzer (1990); Lavallee et al. _ (1993); Weissel et al. (1994); Lovejoy et al. (1995); Pecknold et al. (1997); Tchiguirinskaia et al. (2000); Gagnon et al. (2003), J.-S. Gagnon et al. (2006). A similar mono vs multifractal study exists for the arti_cial growth surface models (e.g., Morel et al., 2000). The growth models are studied in both context of monofractality and multifractality (Bouchaud et al., 1993; Schmittbuhl et al., 1995).
In this Section we use the box-counting method to estimate the fractal dimension of the height pro_le in Iran. In this method we consider the Iran's topography shown in Fig. 1. We used the Iran's topography grid data with high resolution on a square lattice of size 1500 _ 1320.
The heights fhi;jg are known at each grid node (i; j) distributed between the minimum height hmin = -4398 m and the maximum height hmax = 5149 m. In the box-counting method, we consider a cube of size 500 1320 9547 which covers all the height topography.
The mesh sizes are scaled to unity. At each grid point (i; j), we consider a height column of size 1 1 hi;j with hmin _ hi;j _ hmax. We cover the entire cube with boxes of size 1 1 b, for di_erent length scales b, and then count how many boxes of the grid i.e, Nb, are covering part of the height columns. Then we do the same thing by using a _ner grid with smaller boxes (smaller b). By shrinking the size of the grid repeatedly, we end up more accurately capturing the structure of the pattern of the topography.
If the the topography has a fractal structure, then one would expect the following power-law relation Using the box counting method, the fractal dimension Df of the height pro_le is thus given by the slope of the line when we plot the value of log(Nb) on the y-axis against the value of log(b) on the x-axis i.e., (6)As shown in FIG. 2, we _nd that the fractal dimension of the Iran's topography is Df = 2:20(1).
Result and discuion:We find that _(2) = 0:99(0) which gives the roughness exponent _ = _(2)=2 = 0:495(5) in accord with our previous estimates obtained from di_erent methods like the power spectrum analysis and two methods mentioned in Subsections IVA and IV B. We also _nd the higher moment exponents _(3) = 1:39(1) and _(4) = 1:53(1). As mentioned above, for self-a_ne surface one should _nd _(q) = q_ or equivalently, _(q)=q = _. If we test this criteria for Iran's topography, we _nd that _(3)=3 = 0:46(1) and _(4)=4 = 0:38(1) which di_er from our estimate for the roughness exponent _ = 0:495(5). This completes our conclusion that the height pro_le of Iran's topography has a multifractal statistics.

Given the fact that the physical development of cities causes them to be confronted with the topographic and geomorphological units around them, and given the dynamics of these units, if the physical development of the city does not take place in the right direction, it will cause the dynamic balance of the environment to be lost and may cause damage. The purpose of this study is to investigate geomorphologic constraints and provide optimal directions for physical development in Damghan. For this purpose, firstly, the study area was determined using satellite images and aerial photographs. In the next step, the conditioning factors in physical development of the city were determined using the literature review and extensive field surveys and were provided in ArcGIS10.1 environment. In the next step, the factors were weighted using Analytic Hierarchy Process (AHP) and then, using the TOPSIS model, optimum directions were obtained for the physical development of Damghan. According to the results, land use, slopes and geomorphological barriers factors have the most impact on the physical development of the city of Damghan. The results of the research indicated that the western and southwest directions were rated as the most favorable with 0.886979 and 0.759.592 score and south and north directions, with the score of (0, 0373/0) was considered the most unfavorable aspect of the city's physical development. Respectively. In the southern regions, clay and salt slabs and the influx of sandy soils to residential areas and urban equipment, and in the northern regions flood conifers and local floods are the main geomorphology obstacles to urban development, in contrast, the western and southwestern parts of the country were recognized due to proper slope and lithology, lack of geomorphological barriers and lack of agricultural use for physical development of the city. The results of this research can help urban managers and planners in the field of physical development of the city.

The present study was performed to investigate the effects of slope percentage and land use type on the produced sediment by an artificial rainfall simulator in Kakasharaf watershed, a branch of Karkhe watershed (Lorestan province). The rainfall simulator used in this research was designed and constructed by the Soil Conservation and Watershed Management Institute. This device is a portable non-pressurized piston gun with the dimensions of 119.5 × 83 cm and a height of 1.60 m. The rainfall simulator was calibrated and adjusted to the location of the test based on the maximum rainfall intensity of 30 minutes. In order to select the location of the test, after designing the units, land use, and mapping of the slopes of the studied basin, six sub-basins with the three types of forest, pasture and agriculture were selected. After collecting and recording the data, SAS and Excel softwares were used for statistical analysis and plotting. One-way analysis of variance and comparison of means were done based on Duncan test at 1% level.Results 
The average of sediment yield obtained from rainfall simulator in three slope classes and three land uses in sub-basins of the study area showed that in three different land uses, by increasing slope percentage, the amount of sediment yield increased. This trend was not observed in the forest and agricultural land uses in sub-basins 2 and 4, and the amount of sediment yield did not correlate with the increase in slope percentage. The reason for this can be attributed to the effect of some soil characteristics such as the percentage of lime, organic matter, clay content, soil nitrogen and pH of these hill slopes. The amount of sediment yield in different sub-basins, i.e. in rangeland uses in basin of six with a mean sediment of 95.9, and in sub basin five with a mean sediment of 95.75 g in the plot, respectively, had the highest and lowest amount of sediment in pasture land uses. In agricultural land use, the highest sediment yield measured in sub-basin 2 indicated an average of 85.86g and the lowest sediment in the sub-basin showed a mean sediment of 33.31 in the plot area. Also, in 5th basin with a sediment of 1.444 g and in the sixth basin with a mean sediment of 32.27 g, the highest and lowest amount of sediment was produced on the plot area and in the forest land uses. In general, the average sediment yields from the rain fall simulator in the entire Kakashpour area at 10, 20 and 30 percent slopes were 7.49, 23.41 and 61.66 grams, respectively. By increasing the amount of slope percentage, the amount of sediment yield increased as well. The average amounts of sediment at the plot area in the forest, pasture and agriculture were 46.07, 30.88 and 15.02, respectively.Discussion & The results showed that the average quantities of sediment resulted from the plot area with one square meter of rainfall simulator in Kakasharaf watershed were obtained as 7.49, 23.41 and 61.06 g in the slope degrees of 10, 20 and 30%, respectively, and 46.07, 30.88 and 15.02 g in the three land use types of forest, pasture and agriculture, respectively. Therefore, the highest sediment quantity was produced in the slope degree of 30% and forest land use due to the mature forest soils exposed to erosion because of the destruction of forest soils by farmers. Analysis of variance showed a significant difference (p<0.05) between the different sub-basins from the viewpoint of the produced sediment. Also, the interaction effect between sub-basin and land use type on the produced sediment indicated a significant difference at 0.01. Also, the results of Duncan`s mean comparison test indicated a significant difference between the land slope degrees and also between three land use types of pasture, forest and agriculture in terms of the produced sediment and the sediment increased significantly with an increase in the slope  rate from 10% to 30%. Based on the results of the Pearson correlation matrix, soil properties did not have a meaningful correlation with soil loss. The results of sediment yield in different uses indicated that the highest amount of sediment was in the forest and the lowest amount referred to the agricultural land. The reason of this result could be the activity of microorganisms and earthworms that increase porosity and organic matter, and lower specific gravity of soil particles that are more easily displaced by runoff. Also, the soil of forest land use in this area has become dense and hardened due to the easy access of the people of the area, and the continuous cutting of trees. In agricultural lands due to the use of organic fertilizers and the presence of straw after harvesting (which can increase organic matter) as well as the continuous tillage operations in soil, soil permeability can increase. Therefore, the amount of sediment yield was higher in rangelands and forests due to the excessive grazing and the frequent transportation of livestock and, consequently, a decrease in the permeability rate of the soil. The results also showed that the increase in the slope amounts would trigger the sediment yield increase as well. The reason is its effect on the speed of runoff and partly due to the intensification of the effects of rain drops (Toy et al., 2002). Their results showed that the effect of slope percentage on runoff and sediment was significant. Slope amount had a positive effect on the amount of separation of soil particles due to the impact of rain drops.The results of the analysis of variance and the comparison of the mean of the sediment yield in the six sub-basins showed that there is a significant difference between the sediment yields of the sub-basins at the 5% level. The reason for this difference can be attributed to various conditions such as topography of the area, geology, soil characteristics, land use in each sub-basin, as well as the impact of human and managerial factors in the sub-basins, which ultimately affect the amount of sediment produced in the six sub-basins.

In this study, 10 precipitation systems were selected as prototypes between October and June 2016-2015. Then, 70 stations from the country's satellite stations were divided into four general groups in the south, southwest and center of Iran. The daily precipitation of the stations was extracted from each platform. To determine the patterns of precipitation occurrence in the Sudan low pressure region, atmospheric data from 1000 to 500 HPa are extracted from the NCEP / NCAR site and in the GRADS the maps of these ten systems were mapped. One of the most important systems that provide rainfalls in the Middle East is Sudan low pressure Lashkari (1996). The results showed that the systems entering Iran and the Middle East from the mentioned Sudan low pressure have a special mechanism. These systems have strong convection mechanisms because of having a thermal nature in their source and receiving a huge amount of moisture from the surrounding warm seas. They form deep boiling clouds and cause intensive and torrential showers when accompanied by deep waves in layers 700 and 850 HPa. Therefore, the cloud always forms in a convective way, and the height does not play a significant role in the intensification of its precipitations. In other words, it does not have a significant role by itself, at least in the windward slopes of the Zagros Mountains. The intensity of precipitation is, therefore, sometimes higher in the plains compared to the mountain summits. It seems heights play a more effective role in elevations above 1,500 meters in both windward and leeward slopes. However, in the Alborz mountain chain, there is a very clear and impressive correlation between precipitation and height because of re-creation of systems

Soil erosion is one of environmental problems in northern Khorasan province and Badranloo basin. Surveys show that about 461574 tons of soil are eroded from the loess fertile lands of the Badranloo basin annually which has led to a decrease in soil fertility and accumulation of sediment. The sediment resulting from erosion reduces the useful life of dams and water structures in the low stream of basin. The aim of this study was quantitative evaluation of water erosion in the Badranloo basin and the Experimental erosion Potential Method (EPM) has been used in this regard. In this study, within evaluating the water erosion, the specific sediment value for sub-basins and the whole of Badranloo watershed is calculated by ILWIS 3.3 software and specific sediment yield map (GSp) was prepared. ANOVA method was used in SPSS software for analyzing the geological and escalation erosion, along with for statistical analysis of the role of topographic factors in the severity of soil erosion. The results indicate the alarming state of ecological instability in the basin area. So, the annual average water erosion of soil in the basin is about 23.73 ton / ha. Among sub-basins, the sub-basin No. 4 located in the center of the basin with an annual concentration of about 63.89 ton / ha has the highest soil erosion. Groove and mass erosion are common water erosions at the basin level. In addition to lithology conditions and land -use change, among topographic factors, slope and direction of gradient have the greatest effect on the severity of the soil erosion of the basin due to the high correlation.

Drainage density is an important hydrogeomorphologic indicator in determining activity quality of processes of overland run-off, flood intensity, soil erosion and sedimentation load in the basin. Drainage density was defined as the ratio of the total length of streams in a watershed over its contributing area. It describes the degree of drainage network development and was recognized by many authors to be significantly effective on the formation of flood flows. Drainage density is higher in arid areas with sparse vegetation cover. The higher the drainage density, the lower the infiltration and the faster the movement of the surface flow. The structure of watershed topography depends to a large extent on the interaction between slope and channel processes. The applicability of these relatively simple summaries, however, needs to be examined carefully. It is still uncertain how the development of drainage systems with time affects the relation of drainage density with lithology, slope, aspect and elevation. The Behrestagh watershed is a sub-basin of Haraz River basin where in varied geological and topographic conditions and the many overland flow cause soil erosion and destruction of pastures and gardens of the area. This study examines the relationship of drainage density with Geology and topography factors for Behrestagh watershed.
The Behrestagh watershed lies between the latitudes of 35° 56΄ N to 35° 59΄ N and longitudes of 52° 16΄ E to 52° 22΄ E. The main stream in the area is Haraz River. Topographic elevations in the study area vary between 1172 to 3548 m. Here, in order to examine drainage density in the studied area, map of the watershed’s streams was prepared first using GIS and Digital Elevation Model (DEM) of that area. Then, effective Geology and topographical properties including lithology, elevation, slope and aspect was considered and classified in ArcGIS environment and finally were overlaid with the streams as a dependent variable. Accordingly, sum of streams length per unit of each factor was calculated and drainage density was obtained. Data were analyzed in SPSS 20. Moreover, collected data were described using descriptive statistics (tables, charts, abundance distribution, mean and standard deviation). Data analysis was performed using one-way ANOVA to obtain differences with other studied variables.
Discussion of In this study, data analysis was performed using one-way ANOVA to obtain differences with studied variables. Results of the statistical test indicated that the relationship of lithology and slope with drainage density in the considered area was significant at .95 and .99 level of confidence, respectively. The relationship of drainage density with elevation and aspect was not significant, as well. The results showed that the most drainage density of the area was observed in elevation lower than 1400 meters (average density of 8.24). Also, the cretaceous melaphyre formation (km) with average density of 8.79 and the slope class of 20 -30 percent showed an average density of 10.7 and the western aspect (domain direction) indicated an average of 5.57.
To determine the geology and topography factors influencing drainage density, data layers of lithology, slope, aspect and elevation were analyzed through overlaying the dispersion map of the watershed’s streams. The results showed that cretaceous melaphyre formation, elevation below 1400 meters, slope of 20-30 percent and the west aspect are sensitive to streams. Also, results indicated a significant relationship between lithology and slope with drainage density in the considered area and slope was found to be the most important topography factor affecting drainage density. Therefore can used from these variables to assess erosion intensity and its control.

Soil erosion is one of the most important environmental problems we face today. Increasing human exploitation and lack of proper management of the natural environment has a great impact on intensifying the process of soil degradation and erosion. In this study, the erosion and sediment yield in a Kohpayeh - segzi plain with 136 thousand hectares were studied using the Revised Universal Soil Erosion Model (RUSLE). Data and tools used in the study included Weather stations data, Information 21soil sample, digital elevation model (DEM), Satellite image OLI sensors, geographic information system (GIS) and remote sensing (RS). by investigation efficient parameters in RUSLE model, including rain erosion factor, K-factor, the factor is the topography, vegetation factor, and protective operations factor, The amount of the erosion in the region has been estimated. Accordingly, on the result the annual erosion in the entire study area has been estimated zero to 95 tons of soil per hectare per year. The results showed that topographical factor with the highest coefficient of determination (R2=0.9) has the greatest impact on estimates of annual soil erosion using RUSLE model. This research approves the effectiveness of new technologies, GIS and remote sensing for estimating soil erosion.