Showing 193 results for Mohammad
Bakhtiar Feizizadeh, Ali Khedmat Zadeh, Mohammad Reza Nikjoo,,
Volume 18, Issue 48 (3-2018)
Abstract
Remote sensing technology is one of the most efficient and innovative technologies for agricultural land use/cover mapping. In this regard, the object-based Image Analysis (OBIA) is known as a new method of satellite image processing which integrates spatial and spectral information for satellite image process. This approach make use of spectral, environmental, physical and geometrical characteristics (e.g. texture, shape) together images contexts for modeling of land use/cover classes. The main objective of this study is to classify micro land use/cover of Meyandoab County by applying appropriate and effective algorithms and parameters in the object based approach. For this goal, Quick Bird and Aster satellite images were used within the integrated approach for processing and land use modeling. Accordingly, the land use map was classified in 9 class based on spectral and spatial characteristics. In order to perform OBIA, the segmentation was applied in the scale of 10, shape parameter of 0.7 as well as the compactness of 0.3. In terms of the classification task, fuzzy based algorithm and operators (AND, OR) was applied to detriment the membership functionality of segments for each class as well as classifying the related objects. We also applied textures, geometric, NDVI, GLCM, brightness algorithms based on fuzzy operators and assign class algorithm. In order to applying the validation of results, the accuracy assessment step was performed and the finally overall accuracy of 93.6 was obtained for the derived map. The Kappa coefficient was also detriment to be 0.92. The area under cultivation included respectively for lands of wheat and barley, prunes and plums, apples, vineyards and alfalfa hay2622.42, 4505, 4354.55, 4457.85, 14110.58 hectares.
Naseh Qaderi, Bohloul Alijani, Zahra Hejazizadeh, Mohammad Saligheh,
Volume 18, Issue 48 (3-2018)
Abstract
Wheat is the main focus of the economy of Kurdistan province in which the annual fluctuation of wheat yield is 4/11 times as affected by the climatic elements of the site. This study investigated the role of agro-climatic variables and indices on rainfed wheat yield in Kurdistan province. The data of planting area, amount of production, damages and yield of wheat of 31-year in 10 regions of Kurdistan along with the hourly, daily, decade, monthly, seasonal and yearly levels data of 22 synoptic stations were collected. The correlation between wheat yield and 128 independent variables was calculated. The effect of variables on yield evaluated by multivariate regression. The spatial analysis of variables was performed and the spatial model of wheat yield was introduced for province and regions. The results showed that climatic elements in various regions are different, in a 99% confidence. Most of the independent variables alone have a significant effect on wheat yield, but in the stepwise model, 7 variables such as: the number of rainy days of the year, the sum of the degree hours (of temperature less than -11 ° C) in germination and tilling stage, annual precipitation and the precipitation of November are determinants of the yield. Yield and effective independent variables have significant spatial differences even in a cluster climate type. The highest and lowest coefficient of variation of wheat yield is related to Bijar and Kamyaran areas, respectively. Kamyaran and Sanandaj regions have the highest and lowest yield, respectively. Bijar is the highest risk region of the province for wheat production.
The results of this study showed that with a 99 percent confidence, climatic elements (variables) vary in different regions. Most of the independent variables have a significant effect on wheat yield in simple linear regression, but in Stepwise method, due to the internal correlation between variables, just variables entered that have insignificant correlation with each other and have more effects than other variables. The variables affecting the performance are differentin various regions, and from the point of view of effectiveness, the arrangement of the variables in different areas vary too. In other words, even in two regions with a climatic type (based on the Modified De Martonne method), both agro-climatic indices and wheat yield are significantly different. The impact of effective variables on yield at any time and place depends on the time of year and the phonological stage of wheat. At one time the environmental conditions of different regions in terms of temperature, humidity and precipitation differ, based on phonological stages of the regions. The time of the vulnerability of wheat varies from place to place. Wheat vulnerability at flowering stage is more than other stages. The effect of independent variables on yield at different times of year is proportional to the phonological stage in years Different and different in different regions. In Kurdistan province, the number of rainy days of the year, total degree hours the temperature reaches below -11 °C (sum of hours with below -11 °C temperature) from germination to tillering stage, the annual precipitation, the rainfall in the fifth decade of the water year (the precipitation of 11-20 of November), annual relative humidity and total degree hours the temperature reaches above 30°Ctemperature (sum of hours with above 30 °C temperature) in milky and dough stage is the determinants of the production of rainfed wheat. In Baneh and Marivan areas, the coefficient of variation (CV) is lower and in Bijar and Divandareh regions CV is more than other regions. Kamyaran region has the highest yield, Baneh and Marivan were ranked secondjointly. Sanandaj and then Bijarhave the lowest yield. Each region has a model for wheat yield and determinant factors vary from region to region. Although the annual production of Bijar is higher than other areas, wheat production in the Bijar region has a higher risk than other areas.
Mostafa Mohammadi Dehcheshme, Nahid Sajadian, Ali Shojaian, Narges Gheysari,
Volume 18, Issue 48 (3-2018)
Abstract
Study how to relax and leisure from the work of citizens it is located in the field of leisure geography studies. The current study is practical in an aim and descriptive– analytical in method and practical– theoretical in nature. In this study, the first path analysis model was used in order to express logical correlations between environmental and demographics variables, on leisure geography and providing structural analysis.the results of study path analysis model shows that the impacts of the physical environment outside the home with standardized coefficients0.461 into other variables have the greatest impact and demographic variables with standard coefficients 0.025 has least impact on leisure geography of metropolis. In the following, the number of 383 questionnaires was distributed in order to study comparatively the spatial pattern leisure geography among citizen's zones 2, 4 and 7 of the city of Ahvaz that they were at different levels of enjoyment. The results of the questionnaire of citizens indicate that leisure pattern in Region2 is different from other areas; However, the pattern of citizens leisure of district4 and7 has not a significant difference together. In this context, assigning a specific type of planning is approved in order to improve the quality of community health and welfare of the citizens;; with regard to natural and human environment conditions of the city and leisure facilities available.
Chenoor Mohammadi, Manouchehr Farajzadeh, Yousef Ghavdel Rahimi, Abbas Ali Aliakbar Bidokhti,
Volume 18, Issue 48 (3-2018)
Abstract
This study is aimed at estimating monthly mean air temperature (Ta) using the MODIS Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI), latitude, altitude, slope gradient and land use data during 2001-2015. The results showed that despite some spatial similarities between annual spatial patterns of Ta and LST, their variations are significantly different, so that the Ta variation coefficient is four times the one of the LST. Our analysis indicated that while in winter latitude is the key factor in explaining the distribution of the differences LST-Ta, in other seasons the role of slope and vegetation become more prominent. After obtaining the spatial patterns of LST and Ta, we estimated Ta using regression models in spatial resolution of 0.125˚. The lowest estimation error was found in the months of November and December with a high explanatory coefficient (R2) of 70% and a standard error of 1 ° C. On the other hand, the maximum error was obtained from May to August with R2 between 59 to 63% and a standard error of 1.6 ° C which is significant at the 0.05 level. In addition, result of evaluation of individual months showed that estimation of Ta is more accurate at the cold months of the year (November, December, January, February, and March). With considering different land uses, the highest R2 was related to waters and urban areas (96 to 99%) in warm months, and the lowest R2 was for mixed forest and grassland (between 15 and 36%) in cold months.
Dr Mohammad Hossien Saraei, Mrs Samaneh Iraji,
Volume 18, Issue 48 (3-2018)
Abstract
The management of land development in the compilation of urban development documents is a very important topic. Failure to pay attention to this necessity, and the course of physical development foreseen for urban areas, make the main goal of the development plan, which improves the quality of housing in urban areas, not being realized. The purpose of this study is to introduce a functional model for land development management in order to guide and manage the urban development flow. To this end, the Land Readjustment Plan (LR) as the selected method of land management in urban areas is introduced and it is possible to perform it in a range of Yazd city. The general research method used in this descriptive-analytic study. The data used in this article collected by the library method as well as the field survey were used and analyzed using ArcGIS software. In this regard, a proposal for the scope of the study was compiled and evaluated before and after the implementation of the plan. The calculation of the distributional index showed that the proposed scheme would give 20% of the profits to the owners in the scope of the study. The conclusion from this study shows that using the Land Readjustment Program as an economic and design tool, planning and redevelopment of undeveloped lands can be done in accordance with urban needs. This planning involves modifying the layout of parts, modifying the network of roads, supplying services and infrastructure of the facility. Thus, the field of realization of urban development plans in these areas was provided. It also provided the basis for the participation of all stakeholder groups through creating the necessary attractions for the groups influencing the implementation of the project.
Tayebeh Dehghani, Mohammad Saligheh, Bohloul Alijani,
Volume 18, Issue 49 (3-2018)
Abstract
In order to detect climate change, a variety of climate indicators can be used which is often considered temperature and precipitation. In order to investigate the effect of climate change on the amount of precipitation in the north coast of the Persian Gulf, it simulated the precipitable water for 2017-2050 based on the RCP4.5 model of the Hadcm3 model. The NCEP / NCAR base-station data with an arc-value of 0.125 was used to analyze the past and present precipitable water patterns and to reveal the process of this time series. Time series analysis of precipitable water was performed using two SENS tilt estimators and Man-Kendall test. The results indicated that the annual time series of rain water was increasing in the region, every year, 0.05 mm, the precipitated water increased and it tended to become more homogeneous, this increase in the significance level of 0.95. The precipitation rate in the eastern part of the region was higher than other areas. Before 1989, several fluctuations were observed in the rainy season of precipitable water, but none was statistically significant at the confidence level of 95%, but since 1989, the trend has increased significantly at a confidence level of 0.95. This spatial behavior of precipitable water can actually have occurred in response to the increase in the overall temperature of the area and can be considered as a profile of climate change in the region.
Ali Reza Rahimi, Ali Reza Karbalaee Doree, Mohammad Reza Karbalaee,
Volume 18, Issue 49 (3-2018)
Abstract
One of the most important parameters in maximal use of radiant energy is the proper deployment of photovoltaic. The purpose of this study was to determine the optimum setting and tilt for installing photovoltaic panel in Kashan city. For this purpose, using the Masters Gilbert physical relations and relationships, the radiation received on the surface of the panel is calculated. The results of this study indicate that the amount of radiation received on the collector's surface in the south and in different slopes, 64 percent of the time of year, is more than the radiation on the panel surface mounted in the direction of the southeast or west with different slope angles. The highest amount of radiation is in the Azimuth to the south at a gradient of 30 degrees and 40 degrees; Southwest Azimuth (30 degrees) is almost similar to the South Azimuth and only in the southeast west, in summer, glides near the verge, they receive more radiation than the south. The amount of radiation received on the surface of the panel in the direction of south east west (Azimuth 60 °) on different slopes in 87% of the year is greater than the radiation on the panel surface mounted east or west (90 ° azimuth) with different slope angles. By comparing the results, it turns out that the direction of the photovoltaic panel installation will change, as the south changes to the east or west, the intensity of radiation will decrease in the days of the year. The highest photovoltaic energy output in Kashan is in the direction to the south, and with the angle of installation of photovoltaic panel 30 degrees from the horizon line. The most suitable slope for mounting panels between 30 and 40 degrees was obtained from other slopes.
Sayyed Mohammad Hosseini,
Volume 18, Issue 49 (3-2018)
Abstract
Precipitation is a climatic elements that have temporal - spatial distribution. In this research database of Global Precipitation Climatology Centre (GPCC) with a resolution 0.5×0.5 degree for 50 year is used, that was constituted with dimensions of 12800*600. Temporal data are on the columns and pixels (spatial data) located on the rows. The results show an increasing trend in spring and fall but in summer and winter precipitation trend has been decreased. The most amount of precipitation is located in the northern parts of the Black Sea and Mediterranean Sea, Southeast Asia, southern coast of the Caspian and Central Zagros Mountains. Most of Middle East (about %95) have not trend and only in some parts of Kazakhstan, Afghanistan, Pakistan ,central Iran, and areas in lower-latitude have positive trend and some East and northwest parts of Iran and some parts of Middle East also have decreasing trend of precipitation. The highest percent of area of precipitation trend gradient is 0 to 0.5.
Fatemeh Mohammadyary, Hamidreza Pourkhabbaz, Hossin Aghdar, Morteza Tavakoly,
Volume 18, Issue 50 (3-2018)
Abstract
Land-use change is one of the most important challenges of land-use planning that lies with planners, decision-makers and policymakers and has a direct impact on many issues, such as economic growth and the quality of the environment. The present study examines the land use change trends in Behbahan city for 2014 and 2028 using LCM in the GIS environment. Analysis and visibility of user variations, carried out in two periods of Landsat satellite images of 2000 (ETM + sensor) and 2014 (OLI sensors), and land cover maps for each year. The transmission potential modeling was performed by using the multi-layer perceptron artificial neural network algorithm using six independent variables and the distribution of changes in user usage were calculated by Markov chain method. The results of the prediction showed that the most reduction in the changes is the degradation of the rangelands and the greatest increase in the area of agricultural use. According to the horizontal tabulation results of the 2028 map, it can be stated that from the total area of the area 28336.22 hectares of land were unchanged and 33223.78 hectares of land use change. Also Rangeland and forest degradation during this time period can be a danger to urban planners and natural resources.
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Hassan Afrakhteh, Mohammad Hajipur, Farhad Javan,
Volume 18, Issue 50 (3-2018)
Abstract
The oil has gradually obtained a predominant place in national economy since 1950 and nowadays, is the main important resource securing country financial needs. Two questions are the base of this research regarding contradiction of oil rent and traditional economic sectors including agriculture and livestock rearing which always have been intensified. These two questions are as follows: what are the impacts of oil wealth distribution among different regions on Iran's rural economic structure? What has been the locational-spatial consequences of this oil wealth distribution on agricultural sector as a main element of Iran's rural economic structure? Research required data have collected based on document study on the country during 2006- 2011. Collected data are analyzed based on Shift-Share Analysis and Gibbs- Martin methods. Result show that there have not been any incentive in the local, regional and national management for strengthening rural economic structure using oil wealth. In addition, absence of industrial sector in rural economic structure with emphasis on agricultural sector both from policy making view and credit securing show that there have not been any logical sight on the political economic system facing rural space economy for development.
Mohammad Daraei, Dr Peyman Mahmoudi, Dr Behroz Sari Sarraf, Dr Ali Mohammad Khorshiddost,
Volume 18, Issue 50 (3-2018)
Abstract
Agricultural sector is most dependent on climate, and climate is the main determinant of time, location, production resources, and productivity of agricultural activities. The first event of zero-degree temperature in fall and its last event in spring is important for agriculture. This information is used to determine the species suitable for planting in each area. The present study seeks to identify the probability distribution function for extracting statistical characteristics of frost events in Iran. For this purpose, the history of early autumn and late spring frosts were extracted using daily minimum temperatures of 44 synoptic stations in Iran for a period of 30 years (1981-2010). After fitting various distributions, the best distribution was selected using Anderson-Darling goodness of fit test. Results indicated that most stations follow the Wakeby distribution. Based on the calculations, the first day of frost occurs in the highlands of the Northwest (Saqez, Hamedan, Ardabil, and Zanjan), Northeast (Bojnoord, Torbat-e Heydariyeh, Birjand, and also the Central Zagros Mountains (Shahr-e Kord), due to proximity with cold lands of the North such as Siberia and Northern Europe as well as early entry of westerly winds to this region compared to other regions of Iran will occur. And the latest event of the first day of frost occurs a little farther from the southern coast of Iran in a narrow strip along the coast and parts of the northern coasts (from Babolsar to Bandar Anzali). The earliest event of the last day of frost occurs in the same area in early February. The latest day of frost in Iran occurs in Azerbaijan, Kurdistan, Khorasan, and highlands of the province of Chahar Mahal and Bakhtiari
Mrs Masooume Darmani, Mohammad Nohtani, Haydeh Ara, Ali Golkarian, Salman Sharif Azari,
Volume 18, Issue 51 (6-2018)
Abstract
One of the most important processes of erosion and sediment transport in streams is the river most complex engineering issues.this process special effects on water quality indices, action suburbs floor and destroyed much damage to the river and also into the development plans Lack of continuity sediment sampling and measurement of many existing stations. due to the low number of hydrometric stations in Iran and the lack of continuity of sediment sampling and measuring in many existing stations, on one hand the exact amount of sediment load in many rivers in the country is not available and because of differences in climatic, hydrological and topographical conditions in the country, on the other hand, the preparation and calibration of sediment Erosion Models different regions, is unavoidableCalibration models of erosion and sedimentation in different locations is difficult and requires financial capital andthe time . the But evolutionary optimization algorithm able to resolve this problems of mathematical and experimental methods in this paper, a new optimization algorithm spiders can be made to education And the evolutionary pattern for input (discharge and precipitation) and rain-gauge gauging stations and Watershed Kardeh designated evolutionary algorithms and artificial network performance for 24 year 24-year dam catchment Kardeh for the period studied. In conclusion, the results proved that social spiders optimization algorithm t better resultspredic to for sediment in watershed Kardeh
Parviz Kardavani, Farideh Asadian, Mohammad Reza Fallah,
Volume 18, Issue 51 (6-2018)
Abstract
Indiscriminate exploitation of underground aquifers shahriar Plain loss of ground water in the region has created. Water penetration can increase the volume of groundwater reservoir and reduce the loss of it. One way of artificial recharge of aquifers, infiltration of water from riverbeds or running water. In this study, we have tried By examining the characteristics of Karaj River and its flood flows, parameters infiltration GIS examined, For this purpose, The different factors affecting this environment GIS to prepare maps of each factor was prepared. Then using acquired the weight of each layer map by weighted factors to locate the combine And using Boolean logic final map in two classes and is not appropriate was prepared. by matching the map obtained with the river Karaj identified were Due to Construction Dam Amir Kabir And the supply of drinking water in Tehran harvest Abundant by pools traditional and modern Drbaladst Karaj River, Karaj River with flood flows its role Lower in improving groundwater Shahriar Plain is capable.
Dr Mohammad Mahdi Hoseinzadeh, Dr , Mis Sepide Imeni,
Volume 18, Issue 51 (6-2018)
Abstract
The process of precipitation – runoff of each basin, is influenced by hydrologic, geomorphology conditions, geological formation and vegetation. There are different methods in drainage basins. One way to estimate the runoff height is Curve Number (CN) method. That reperesents the hydrological behavior of basin. data were collected for statistics of climate and then topographic map of 1: 25000 and geological map of 1: 100000 by GSI was used. Smada software for calculate the short – term rainfall at different return periods. As well as Arc GIS software for mapping Curve Number by combining maps of land use, soil hydrological groups and moisture of soil with using the table of America Soil Conservation Service (SCS). And then modeling related in the GIS mappings of runoff height of Hesarak catchment was prepared. The aim of this study, was to determine Curve Number and estimate runoff coefficient and maximum discharge runoff with SCS method in various units catchment is. The results showed, hydrologic condition and soil hydrological groups are the most important parameters to determine the CN and affect on runoff. The most potential for runoff is in downstream of basin that specified with urban land use. Also average weight of Curve Numbers those obtained for each sub catchments, Chapdareh sub catchment (S2) with 88 Cure Number and mean of runoff 28.15 mm had the highest volume of runoff, Dochenaran sub catchment (S3) with 89.3 Curve Number and mean of runoff 24.54 mm and sub catchment of the twin branches (S1) with 90.1 Curve Number and mean of runoff 17.36 mm had The lowest amount of runoff probability and spill potential. But in general potential runoff in this basin is relatively high. The maximum amount of runoff Curve Number in condition of high humidity is 99 and 78 is the lowest.
Doctor Maryam Ilanloo, Sir Hosein Bicgarian, Sir Mohsen Yahya Soltani, Sir Mohammad Mehdi Bahramian,
Volume 19, Issue 52 (3-2019)
Abstract
Solid waste is an integral part of human life, generation of various quantities and qualities of which is one of the greatest environmental problems of the current era. Application of modern tools and technology to find the right place for recycling, where the volume of recyclable materials can be reduced, seems vital for reusing the recoverable materials contained in normal waste and their recycling and reusing in the cycle of industry. The study aimed to find a location for recycling and its converting industries in Kelardasht, Iran. This was a descriptive and analytical research with a survey approach. At first, experts of the field were recognized and a scientific panel was formed to identify the relevant criteria through Delphi method. In this respect, five criteria of the distance from residential and commercial areas, the distance from urban streets, the distance from the river, the distance from the hospital and education centers, and the distance from hotels, banks, and offices were selected. After that, the permitted distances for these criteria were determined by Delphi technique, followed by the application of the centroid method to determine the exact distances. Moreover, the analytical hierarchy process (AHP) and geographic information system (GIS) were exploited to determine the and use weights in raster maps and generation of the zoning map. Furthermore, the best locations for recycling were selected in Kelardasht using field survey method and based on the zoning map. According to the results, four sites were selected for recycling of recoverable solid waste in this region
Mr Sirous Hashemi Darebadami, Dr Ali Darvishi Boloorani, Dr Seyed Kazem Alavipanah, Mr Mohammad Maleki, Mr Reza Bayat,
Volume 19, Issue 52 (3-2019)
Abstract
The term urban heat island (UHI), described the phenomenon of climate change in urban areas compared with surrounding rural areas. UHI effects include: increasing in energy and water consumption, air pollution expansion and interfering in thermal comfort. Surface urban heat island (SUHI) contains patterns of land surface temperature (LST) in urban areas that has interaction with UHI in urban canopy layer and urban boundary layer and investigate with thermal remote sensing. SUHI has diurnal and seasonal variations so requires multi-temporal data to analysis SUHI. In this study, the multi-temporal MODIS (Aqua and Terra) data product were used to analyze the SUHI in day and night in Tehran metropolitan. Physical and biophysical surface properties such as: land cover/land use (LULC), elevation, albedo, vegetation index (NDVI) and impervious surfaces index (NDBI) were used to interpretation of the LST and SUHI changes. The results showed that SUHI in Tehran, has spatial-temporal diurnal and seasonal variation. So that during warm days the surface urban cool island (SUCL) is formed in Tehran. At night times, SUHI index values was different between 2 and 5 ° C (maximum in the spring). The results also showed that different of land cover thermal properties, albedo and elevation was the most important factors is the diurnal changes of SUHI while phonological changes of vegetation and albedo, was the most important factors in seasonal changes of SUHI.
Mr Ali Mohammadpourzeidi, Professor Bohloul Alijani, Associate Professor of Climatology Mohammad Saligheh, Mr Mohammadsaleh Gerami,
Volume 19, Issue 52 (3-2019)
Abstract
owledge of spatial rainfall behavior in environmental, land planning is effective. These changes in the later place in the form of time later and in the climate of the area. The Target of this study was to reveal the presence or absence of precipitation trend in the ratio of the height of local precipitation behavior and identify province mazandarn. Therefore, the purpose of the rainfall data station 32 (Meteorological Agency and Department of energy), the statistical period 1988-2010. To get the regression analysis of precipitation process was used to identify the local behavior of precipitation, the method of spatial statistics were used. The results obtained from the behavior of precipitation, the existence of the process within the scope of the study and the emphasis is most consistent with the Be modified regression model at adjustment indicate. According to the regional behavior of precipitation, using local spatial statistics, spatial Moran well hot spots check this behavior. The results showed that precipitation in the province of Mazandaran has the pattern of clusters with high value. According to the local hot spots and methods Moran, West Coast up to a height of 700 m has positive z score and clusters with high value, 99% confidence level. This range includes 15% of the total of the province. The range of the Southern Highlands as well as the negative z score and clusters with low value with a confidence level shows 99%. This range is also about 20 per cent of the province's total. About 65 percent of the total area of the province as well as the lack of a significant trend show.
Dr. Mohammad Javad Vahidi, Dr. Rasoul Mirabbasi,
Volume 19, Issue 53 (6-2019)
Abstract
In order to protect soil and water resources should be identified erodible areas of watersheds, to be able to prevent land degradation and to control erosion in the form of soil conservation planning or watershed management. Therefore, the present study aimed to classification and delineation of susceptible areas to water erosion in the Hervi watershed using Hjulstrom curve, has been conducted. Increasing of accuracy, speed and facility of spatial achievement, using GIS technology, are advantages of the present study. In this study, were separated 10 sub-watersheds based on the feeding levels of streams. Spatial variability of soil properties in sub-watersheds, such as texture and the mean diameter size of the particles using hydrometer method were measured; also the maximum potential velocity of outlet in sub-watersheds based on the characteristics of each sub-watershed were calculated. Then, status of erosion and sediment in watersheds and sub-watersheds was studied using Hjulstrom curve (based on the mean diameter size of sediment particles and the maximum potential velocity of outlet), and was comparatively classified in term of erodibility. Finally, delineation map of susceptible regions to water erosion in the study area were obtained. The results revealed that the upstream and side areas of the watershed including: Sub-watershed No.4 (8.94% of the land), has very high erodibility, and Sub-watersheds No.1 and No.9 (36.94% of the land) have high erodibility. These areas are steep and often devoid of vegetation or have poor vegetation (such as poor pastures and rain-fed farming); so, it is necessary a proper strategy to prevent further erosion.
Mohammadreza Goodarzi, Atiyeh Fatehifar,
Volume 19, Issue 53 (6-2019)
Abstract
In the present time, with the increase of industrial activities and the neglected environmental issues, the effects of climate change have become more evident and poses this phenomenon as a global difficult. Increasing the probability of occurrence of extreme climatic events such as flood and increasing the frequency and intensity of the effects of climate change. The northwest of the country is one of the most vulnerable areas of the country due to its semi-arid and mountainous climates and high rainfall variability. Therefore, zoning due to climate change is essential. Therefore, in this study, in order to investigate the risk of flood in the Azarshahr basin, due to climate change, using the CanESM2 general circulation model under RCP8.5 scenarios negativity according to the assessment report fifth IPCC, rainfall and temperature variables were down scaling by Statistical down scaling model (SDSM). Then,with hydrological model SWAT the daily runoff, the basin map and the lines of the canals are achieved. The results of the evaluation of the SDSM model with a coefficient of determination and Nash-Sutcliff 0.95 on average represent the good performance of the model in the down scaling of large scale data. The results show an increase of 0.23 ° C and 4.53% rainfall and maximum discharge. The basin is zoned with the combination of the maximum mean discharge map, the coefficient and distance from the river with the AHP approach. Due to the zoning they are 41.55% of the area of the basin, at very low and low risk, 27.23% at average risk and 31.2% at high and very high risk. Also, with the final map, it became clear that the mid-basin had a high risk due to its prerequisite conditions and that it needed to carry out managerial actions.
Elham Yarahmadi, Mostafa Karampoor, Hooshang Ghaemi, Mohammad Moradi, Behrouz Nasiri,
Volume 19, Issue 53 (6-2019)
Abstract
Investigating of rainfall behavior in the spatial-temporal dimension and determining the tolerance thresholds of different geographical areas with respect to vegetation, animal life and human activities, is essential for any decision in the environment. Therefore, precipitation data of 27 stations were received from the Meteorological Organization during the 60-year period and After the data were evaluated qualitatively, The distribution of temporal and spatial mean, coefficient of variation, skewness and probability distribution of 20% maximum and minimum monthly and seasonal autumn and winter, for a period of 60 years (1951-2010), two 30-year periods (1980-1951), (1981- 2010) and two 10-year periods (2010-2001), (1951-1960) were calculated and were zoned using GIS. Studies show, except on the shores of the Caspian Sea, there is little change between autumn and winter patterns. The average rainfall of the southern shores of the Caspian Sea has decreased to the west and east. in other areas of the country, the spatial and temporal variations of rainfall in the autumn are very highand from the north to the south, the mean decreases and the coefficient of variation and skewness increase. In winter, maintaining the pattern of autumn, the average precipitation increases and the coefficient of variation decreases. The average precipitation of 30 years and 10 years of the second winter season, compared to the first 30 years and 10 years, and also the 60 year period, has decreased in most stations, which is consistent with the results of the Mannkundal test. Analysis and review of the 20% minimum and maximum seasonal rainfall show that the intensity and range of performance of winter precipitation systems in the second 30 years have decreased. Also, the frequency and severity of drought in the autumn season have increased in the second 30 years and in the last 10 years. The highest decline occurred in the western and eastern parts of the Caspian coast and in the northwest, which requires special attention to managers in light of the areas of activity and concentration of the population.
