Showing 123 results for Rs
Murad Kaviani Rad, Afshin Motaghi Disfani, Hossein Mokhtari Hashi, Ahmad Rashidinejad,
Volume 22, Issue 66 (9-2022)
Abstract
International rivers, as borders or crossing national borders, have been considered as a significant part of international relations. Especially, approximately half of the world's population lives within the basin of these rivers, and more than 90% are living in countries with these basins. This condition, by creating an undeniable relationship of interdependence, has made water a critical issue for these countries. Thus, as populations and economies grow and develop and national water resources are exploited for additional growth and development, government action and reaction to a higher share of these transnational sources will increase. By the way, the type of government interaction in line with exploiting these common resources includes a wide range of cooperation to tension and war. In some parts of the world, common water resources in the form of rivers have used as a linking factor between nations and governments. So that, instead of conflict, the beneficiary countries take the path of cooperation and convergence and they have taken important steps with regard to the development of the region as optimal management of common water resources. Although the achievement of international cooperation is a long, lengthy and complex path, always, there are many ways to follow, many steps to take, and many options for appraisal and selection. The current research is a descriptive-analytical research and by means of library resources and examining the practical status of cooperation in a part of the Danube River as a model, concluded that cooperation was not just for water agreements and factors such as environmental concerns, regional security, regional benefits (such as joining organizations and ::union::s), mediation (governments, international organizations, and institutions), etc., are effective in this process.
Khadijeh Haji, Abazar Esmali-Ouri, Raoof Mostafazadeh, Dr Habib Nazarnejad,
Volume 22, Issue 66 (9-2022)
Abstract
Also, because of human activities and natural phenomena, the face of the earth has always undergone a change. Therefore, for optimal management of natural areas, awareness of the ratio of land cover/land use changes is a necessity. Therefore, extraction of land use maps as the most important goal in the management of the natural resource can be considered. The purpose of the present study was to evaluate land cover/ land use changes at the Rozechai Watershed during the period of 30-years 1985-2015 using Landsat 5 and Landsat 7 satellite imageries such as TM and ETM+ sensors; plus, land use maps were prepared using TerrSet software and object-oriented classification in 1985 and 2000 years. As well as the land use map of procurement by the geographical organization in 2015 has been used. The results show that rangelands level has the highest percentage among all land use types during the period of 30 years, but between 1985 and 2000, and 2000 to 2015, the level of rangelands has a decreasing trend indicating the destruction trend in the region of the replacement of moderate- poor rangelands and good rangeland by dry farming. Also, the tables of obtained from the error matrix indicate that the observed values in the diameter of the error matrix are much larger than the values outside the diameters. Thus, the overall accuracy for the years 1985, 2000, and 2015 were 97, 90 and 96 percent, and The values of Kappa index were 91%, 84% and 94% respectively, indicating a high degree of accuracy in the object-oriented approach to classification.
Negar Ghasemi, Marzieh Alikhah Asl, Mohammad Rezvani,
Volume 22, Issue 66 (9-2022)
Abstract
Study of resources changes in previous years could be useful in the planning and optimal using of resources to control inappropriate changes. Because land use changes occur on large-scale, remote sensing technique is a useful and valuable tool for monitoring the changes. The aim of this research is land cover changes detection in a period of 32 years in Pishva town with using remote sensing technique .First TM, ETM and OLI images for the years 1986, 2002 and 2018 were collected respectively and after geometric and radiometric corrections, images were classified by using maximum likelihood classification methods. Kappa and overall indexes were used to calculate classification accuracy. Results showed in past 32 years, bare land and irrigated land have decreased while residential and greenhouse areas have increased. Classification accuracy showed that OLI, ETM and TM sensors have high accuracy respectively with kappa 0.96, 0.80 and 0.76 and also overall indexes of 97.56, 86.54 and 86 percent. Based on results, in the first period (1986-2002) 27.6%, in the second period (2002-2018) 29.60% and in the third period (1986-2018) 31.8% of area land cover have been changed. Results showed land cover changes in the area is related to climate changes like low precipitation, drought and social condition like population and food need increasing and economic condition like high production and efficiency.
D.r Hossein Jahantigh, Amir Bakhshi, Rezvan Ghorbani Salkhord,
Volume 22, Issue 67 (12-2022)
Abstract
Identifying barriers and adaptation requirements is crucial for the successful implementation of climate change adaptation practices at the local level, especially in mountainous rural communities with limited local resources and technology. Due to the importance of this issue, in the present study, the barriers and requirements for adaptation to climate change in mountainous villages were investigated. The present research is descriptive-analytical in terms of purpose and method. The data collection tool was a questionnaire, free interview and observation of the researcher from the study area. The statistical population of rural households is Papi section of Khorramabad city (N = 2346). Using Cochranchr('39')s formula and sampling method, 330 households were selected as a sample. To analyze the data, descriptive statistics and exponential exploratory co-integration rank test (Johansen method) were used. The results showed that farmers in the mountainous villages of the study area face several adaptation barriers that are more serious institutional, normative, technological and information and cognitive barriers. Given that adaptation conditions are an important factor in reducing or eliminating adaptation barriers and improving farmerschr('39') adaptation capacity to climate change, local economic development, local infrastructure, production technology, and the granting of micro-credentials are the most prominent adaptation requirements in these were the grounds. In addition, due to the effective role of government, cooperatives and villagers themselves in rural development, a rational adaptation framework for selecting optimal adaptation strategies in cooperation with these three, as appropriate regional adaptation measures and policies for research proposals was presented.
Dr Gholamabbas Fallah Ghalhari, Fahimeh Shakeri,
Volume 22, Issue 67 (12-2022)
Abstract
In this Research, the maximum temperature of selected stations in Khuzestan province and the numerical values of 8 extreme climatic indicators belonging to the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI) were used in the statistical period of 1987-2017. To analyze the trend of extreme climatic indices, the Man-Kendall test was used and to estimate the slope of the trend line, the Sen’s estimator was used. In this study, given the importance of global warming that severely affected all aspects of life, the authors explore the relationship between climatic factors and maximum temperature in Khuzestan province until to rely on it, and ones can predict and forecast air temperature at this region. For this purpose, the temperature of selected stations in Khuzestan province and numerical values of 8 climate indicators in the period 1987-2014 have been used. To understand the relationship between climate indicators and maximum temperature at 1 to 12 months of delays, Pearson’s correlation coefficient was used. The results showed that most of the extreme climatic indicators in the study period had a significant trend. The TX10 and TN10 indices have had negative trend in most stations and the TX90, TN90, TXx, TXn, TNx and TNn indices have had positive trend. According to the results of correlation coefficients can be concluded that all studied signals have a significant effect on the province's maximum temperature. The correlation between maximum temperature and indices PNA, TSA, WHWP, WP and NAO, was more than the other climate indicators. Results also showed that the entire indices except NAO have significant positive correlation with maximum temperature of the province. PNA index with a delay of 10 months has the highest positive correlation with maximum temperature of study area.
Abolfazl Moarefi, Arash Sadri, Hadi Gholami Norabad, Behzad Saeidi,
Volume 22, Issue 67 (12-2022)
Abstract
As a novel idea for discussion on the role of industrial development on regional development, the term “cluster” became noteworthy since 90’s in order to increase competitiveness. Territorial development researchers believe that formation of regional industrial clusters improves competitiveness and plays a role in promoting competitive advantages and regional development. Hence, because of the possibility of realization of competitive advantage, Tourism clusters became a focal point for research and policy making. Against this background, the purpose of this research is to analyze and review the role of industrial clusters on development of regional competitiveness and assumes that the higher number of relations in an industrial cluster leads to higher level of regional competitiveness. The research applies descriptive-analytical research method and utilizes questionnaire to collect data. The data was studied by SPSS and Lisrel software packs after approval of validity and reliability of data. Findings corroborate the relation between higher number of relations in industrial clusters with higher level of regional competitiveness and also identifies the contributing factors to development and stimulation of regional development which are ranked by the order of their effect as follows: 1. Social relations, 2. Geographic and location relations, 3. Economic relations, and 4. Institutional relations.
Ms Mehdi Kashefi, Dr Mojgan Entezari, Dr Maryam Jafari Aghdam,
Volume 22, Issue 67 (12-2022)
Abstract
vulnerability is considered as an inherent talent of underground water system that depending on the sensitivity of the system to anthropogenic effects. Natural vulnerability is based on the geomorphologic features of surface karst, type and level of aquifer recharge and hydrodynamic aquifer karstic aquifer in Fars province is the most important source of water supply for the supplement of drinking water of communities in the province, which are prone to pollution due to the natural conditions of the region and human activities. karstic aquifer of Shispir and Borghan plays a vital role in supplying drinking and agricultural water around them. The aim of this study is to estimate the natural vulnerability karstic aquifer of Shispir and Borghan using the proposed model of Cast action 620, and prioritize the level of aquifer in the field of conservation measures and provide management solutions in order to better protect them in this model. To prepare a natural vulnerability map are used geological maps, soil, vegetation, digital elevation model (10 meter) and precipitation statistics of meteorological stations and vulnerability map is evaluated as three factors of C, O, p. In the end, the region in terms of damage in five levels was classified in very high, high, low, low and very. The results of the COP model show the natural vulnerability of the region is high. In addition, the amount of vulnerability in the two upper and upper floors of this region is about 47 % where is the highest coverage area of that region of Shisper aquifer. The results of this study show the efficiency of the proposed methods by Cast Action 620 to detect and protection of groundwater resources from vulnerabilities and natural pollution.
Dr Bromand Salahi, Vahid Safarian Zangir,
Volume 23, Issue 68 (3-2023)
Abstract
Global warming and temperature rise will have many effects on different sectors, including agriculture, the warming of the earth will increase the rate of evaporation, and consequently the increase in the demand for agricultural products will increase. In this study, in order to monitor the effect of global warming on Mughan Plain wheat, using the LARS-WG model as a relatively inexpensive and accurate instrument for producing climate multi-yearly climate change scenarios On a daily basis, In Ardabil province, Germi Station was selected as the representative of the three stations in the study area due to the data in the appropriate statistical period. In the present study, to monitor the effect of global warming on precipitation fluctuations, as well as in the production and cultivation of wheat crop in Moghan plain, the LARS-WG model and the HADCM3 climate model output under A1B scenario as well as climate data (minimum temperature, maximum temperature, precipitation and Daily Sunshine) The Germys station was used over a 14 year period (2004-2007).The results of the research show that by comparing the monthly mean of these parameters, this result was obtained that at confidence level 1 there is not a significant difference between the simulation data from the model and observational data in the base period and the mean The climatic parameters of the data obtained from the model and the actual data are similar and there is a high correlation between them. Finally, by comparing observational monthly meanings and modeling of climatic elements of precipitation, minimum and maximum temperatures and sunshine were shown using statistical parameters RMSE, MAE, NA and R2 The model (LARS-WG5) is used to accurately simulate daily data in the parameters of the Mughan Plain, Ardebil province. The results of this study showed that the average decrease in yield of irrigated wheat and the decrease of its production in the study area could be due to the decrease of precipitation and the increase of the regional temperature which is due to global warming.
Mr Omid Mahpeykar, Dr Mohammadreza Khalilabadi,
Volume 23, Issue 68 (3-2023)
Abstract
General circulation of Persian Gulf has a cyclonic pattern that affected by tide, wind stress and thermohaline force. Although tidal force is very effective in values of current speed, but thermohaline force is dominant in long time because tidal forcing has a short period and returning nature. Tide and density parameters are important in navigating and shipping, especially when ships approaching the shore and shallow water to determine the drainage of them. In this study using the Mike model based on the three-dimensional solution of the Navier Stokes equations, assumption of incompressibility, Boussinesq aproximation, and hydrostatic pressure, Persian Gulf circulation modelled. After model stability, the effects of tidal force on horizontal and vertical distribution of density were investigated. Results show that forcing of tide caused current direction be regular and without tidal force, wind stress dominates on isopycnal and turbulent pattern forms in sea surface layer especially in cool season. Also, with the elimination of the tide effect, the velocity of current is reduced to 75% and the water density is increased to 1-2 kg/m3. Density profile show that the Persian Gulf is a baroclinic environment and it is stronger in cool season relative to warm season. The impact of forces is not the same in different regions of the Persian Gulf, so that the effects on the change in density in the Strait of Hormuz are more perceptible and moving inward to the Gulf, the intensity of its effect is reduced.
Somayeh Jahan Tigh Mond , Yassin Zeini Vand, Seyyed Moein Moosavi Nadoshan,
Volume 23, Issue 68 (3-2023)
Abstract
This study aims at organizing the city of Poldokhtar in the city of Kashkan. Using this element of natural value, the city is being restored and organized, and its potential for tourism and development of tourism and economic prosperity is to be used. The paths of the rivers within the city can be used as a linear route, and can be used as a sustainable urban tourism axis. In the case of the spatial and spatial organization of the rivers for such a purpose, various, yet standardized patterns for shaping and managing the length of rivers can be used. Finally, the findings of library studies and the results of a field survey were distributed through a questionnaire and SPSS software using the Cronbach's alpha coefficient, the coefficient obtained in this study was equal to 8,377, which indicates the appropriate credit for Data collection. In the final stage, using the AMOS software and the structural equivalence method, the relationship between the main components of the research and the constituent variables has been analyzed and analyzed. The range of results showed that the most important strategy for creating urban river tourism in Poldokhtar is the attempt to create a social and secure environment with facilities and ease of access and special emphasis on environmental and ecological issues. For this reason, the main criteria for design based on local capabilities are defined. It should be noted that in the social, recreational, historical and environmental areas the same procedure is used, which means that all the spatial and spatial regulation strategies and parameters of the river in line with the native nature and the needs of the people living in the area and in A word of the users of the project has been used.
Asadolah Hejazi, Zahra Heidari,
Volume 23, Issue 68 (3-2023)
Abstract
In recent years, population growth and consequently the shortage of drinking water resources have increased the importance of studying the areas of caries Regarding the importance of the subject, in the present study, the evaluation and monitoring of the developed karstic areas and the potential of contamination of Cartesian resources in the Ravensar basin have been addressed In this study, 7factors were used to evaluate the factors of Karst development in Ravansar basin as well as two methods of OWA and ANP. The method of work is that after the necessary processing, using the OWA method and applying weights obtained through the ANP model, the zoning is done After designing the zoning map, using the satellite imagery of 2007 and2015, the development of human development areas in the developed karstic areas has been evaluated The results of this study indicate that most of the studied basin, especially in northern and western areas of the basin, are highly and relatively developed in the class, The calculation of the area of man-made areas suggests that in2007, about 2.6 km of occupied areas of man-made industrial zones have been occupied which, according to the growing population, increased to 3.8 km in2015, human-made areas have been extracted in developed artisanal areas
Zahra Hejazizadeh, Sharifeh Zarei, ,
Volume 23, Issue 69 (6-2023)
Abstract
Abstract
In recent years, attention has been paid to climate change, which could be the result of economic, social, and financial losses associated with extreme weather events. The purpose of this study is to investigate the variation of extreme temperature and precipitation in Kurdistan province. For this purpose, daily rainfall data, minimum temperature and maximum temperature of 6 stations were used during the statistical period (1990-1990). And their changes during the period (2041-2060) using the universal HadGEM2 model under two scenarios RCP2.6 and RCP8.5 and the LARS-WG6 statistical downscaling were investigated. In order to study the trend of climatic extreme indexes, rainfall and temperature indices were analyzed using RClimdex software. The results showed that during the period (2016-1990), hot extreme indicators have a positive and incremental trend. This trend is significant for the "number of summer days" and "maximum monthly of maximum daily temperature" indicators. This is while the cold extreme indexes had a decreasing and negative trend. This trend was significant only for the "cold days" index. Extreme precipitation in Kurdistan province has a negative trend in most stations. ،this trend is significant at most stations, that indicates a reduction in the severity, duration and frequency of precipitation during the study period. The results of the climate change outlook also indicate that the temperature will increase over the next period and rainfall will decrease.
Tara Heidari Orojloo, Dr Afshin Ghorbani Param, Dr Faramarz Hasanpour,
Volume 23, Issue 69 (6-2023)
Abstract
rchitecture is always influenced by various indicators, the most important of which are climatic and physical-spatial indicators. These indicators are well observed in traditional homes and have played an important role in the use of clean energy. In this study, the aim is to study the climatic and spatial indicators of traditional architecture of Shiraz houses in order to provide a suitable model for housing design in order to use clean energy. The research method is descriptive-analytical and based on data collection through a questionnaire. The validity of the instrument was confirmed by elite and the reliability was confirmed by Cronbach's alpha above 0.70. The statistical population of the research consists of 27089 experts, specialists and people familiar with the architecture of the building and a member of the Engineering System Organization of Fars Province. The number of samples according to Morgan table is 384 people. The result of one-sample t-test showed that all studied climatic and spatial variables including green space, proportions and composition of architectural elements, materials, sustainable architectural design of spaces, building orientation, organizing spaces, water use, maximum use of wind , The use of light and providing coolness with shade at a level less than 0.05 were significant and in terms of the statistical population, were in a good condition. Among the spatial and climatic variables of architecture, the most impact was related to the orientation variable with a value of 4.03 and then green space with an average of 3.85. The regression result showed that the most effective variables in the design of modern houses are related to the variable of proportions and composition of architectural elements with a value of 0.151 units, ie 15%.
Dr Sajedeh Karimi,
Volume 23, Issue 69 (6-2023)
Abstract
Many efforts have been made to address the negative effects of sprawling urban expansion, which can be referred to as "smart growth" as a strategy for urban sustainability. The purpose of this study was to evaluate the impact of smart city growth on economic and social parameters in Isfahan. The present study is descriptive-analytical in terms of the type of research and is applied-developmental in terms of purpose. The statistical population of the study consisted of the population of Isfahan city in the Census of 2016 (5120850). The research tool was a researcher-made questionnaire (Smart City Questionnaire, Economic Questionnaire and Social Questionnaire) with 32 questions. The validity of the questionnaire was formal, which was confirmed by experts and professors, and its reliability by Cronbach's alpha was 0.84. Data analysis, based on structural equation analysis, was performed in AMOS software. The results indicate that urban smart growth in Isfahan is influenced by social and economic variables, among which the role of economic variables in urban smart growth have more influence than social variables, which impact factor of economic variable role. It was 0.71, while the social variable had an impact factor of 0.38.
Ms Elaheh Ghasemi Karakani, Mr Ebrahim Fattahi, Mrs Loabat Salehi Pak, Mr Hooshang Ghaemi,
Volume 23, Issue 69 (6-2023)
Abstract
During the rainfall, the intensity of precipitation varies. Changes in the amount of precipitation during an event of rainfall are effective in the resulting of flood and its intensity. Knowledge of how rainfall changes over time during rainfall is determined by temporal distribution pattern of rainfall. For this purpose, availability of short-term time scales rainfalls data are important that obtained by rain gauge stations. However, the low density of the rain gauge network and the lack of sufficient data from the time pattern of rainfall have always been a problem in determining storm patterns for executive plans. Therefore, the simulation of WRF numerical weather models can be used. The WRF model is one of the most responsive models for predicting precipitation, temperature and atmospheric elements that used in this study. In this paper, three great storm events on 15 December 2003, 24 - 26 December 2006 and 6-7 March 2007 have been selected in the Parsian dam basin and surrounding areas in south west of Iran. The result of WRF numerical weather prediction model for these great storms compared with data loggers. It showed that the WRF model was able to performance the heavy rainfall and simulates the rainfall pattern in these dates.
Nasim Majidizanjani, Mostafa Mokhtabad Emraei, Iraj Etessm,
Volume 23, Issue 69 (6-2023)
Abstract
Since geographical space is a subjective space, due to the difference in the spatial cognation of different people, its perception can be changed from person to person. This cognation depends on the person's experiences of the environment and can be taught. On the other hand, the best age for this training is childhood. But this issue has received less attention. Therefore, the aim of this study was to determine the effect of architectural experiences from the environment on the spatial cognation of students in Tehran. This research was conducted by quasi-experimental method. This was done by measuring the students' perspective perception and wayfinding ability before and after the architectural experiences of the environment. In this regard, pre-test and post-test were used together with the control group. The model used in this study was one-way analysis of covariance (ANOVA). The tests included measuring spatial cognation by perspective perspective drawing by sketching the landscape mental image and wayfinding tasks. For validity measurement, face validity was used and for reliability measurement, Cronbach's alpha was used, which is higher than 0.70 for spatial cognation and its dimensions. Significance in the effectiveness of architectural experiences of the environment in understanding the perspective and the wayfinding ability that are part of spatial knowledge, showed the development of students' cognation of geographical space.
Abolghasem Amir Ahmadi, Leila Goli Mokhtari, Naemi Tebar Mahnaz,
Volume 23, Issue 70 (9-2023)
Abstract
The purpose of this study was to identify evidence of late Quaternary glaciers in the northern highlands of Binalood. Topographic maps, satellite imagery and climatic data are the tools and data used in this study. Arc gis 10.4 software was used for data analysis. Quaternary glacier evidences were identified based on four types of evidences including morphic indices, climatic evidences, geomorphological evidences and laboratory indices. Using morphic indexes, the curve lines were identified on topographic maps of satellite imagery, ice-dominated areas, and the effects of 28 glacial circuses. Climatic evidence shows that not only was Quaternary at about 7 degrees cooler than the present time, but its precipitation was almost twice as high as at present. On the other hand, glacier circles, moraines, thales and glacial mounds were the most prominent geomorphologic evidence of glaciers in the Binaloud Heights. Finally, granulometric laboratory indices supplementing the evidence of glaciers have confirmed the existence of glacial sediments at the Binaloud Heights. Also, using Wright's method, the permanent snow boundary line during the reign of Binalood Heights Glaciers was estimated at 2600 m.
Mr Hasan Yavarian, Dr Hamid Jalalian, Dr Asghar Tahmasebi,
Volume 23, Issue 71 (12-2023)
Abstract
Water Resource plays a pivotal role in sustainable development of every area, especially in rural areas. The challenge of dehydration is one of the greatest challenges in 21st century because it can be the source of many of the world's social and ecological changes. The agricultural sector as the most important economic sector in the rural areas is directly affected by the shortage of water resources. Identifying the attitudes and solutions of indigenous farmers in facing to water deficiency plays a key role in appropriate strategies and improving the capacity of local communities to adapt to it. The purpose of this study was to investigate the attitude of farmers in the villages of Bahar County in Hamadan province toward the challenge of dehydration and identify appropriate strategies and strategies for mitigation and adaptation in the region. This research is a descriptive-analytical study. The statistical population of the study is 68 villages in Bahar County with 18376 households. According to Cochran formula, there was needed to complete the questionnaire by 375 farmers as the number of the samples. The main data were collected through a field survey using a questionnaire. The sampling method was random and the number of samples in each village was determined by proportionate stratified sampling based on the number of farmers and the questionnaires were completed randomly. Data analysis was performed using confirmatory factor analysis in Lizrel software. The attitude of the villagers towards the aridity challenge was respectively cognitive attitude with (0.883), behavioral attitude with (0.867) and emotional attitude with (0.517) of factor analysis. Therefore, it can be concluded that the villagers' attitude to the challenge of dehydration is a cognitive-behavioral. Based on this, 12 strategies consistent with the status of the region have been proposed for optimal resource management and crop water productivity.
Behrouz Hashemi, Farzaneh Sasanpor, Ali Movahed, Habiallah Fasihi,
Volume 23, Issue 71 (12-2023)
Abstract
Abstract
With the rapid growth of population and urbanization since the last century, the complexity and understanding of the spatial organization of the city, as well as the ability to predict urban events in its spaces, have become difficult and in some cases impossible. Karaj metropolis is one of the major metropolitan areas of Iran that has been experiencing rapid population growth and this has led to complexity of space and consequently to complexity of organization recognition and analysis and its spatial structure and impact of livelihood components. It has become a spatial system. The main purpose of the present study is to identify the role and impact of Karaj's spatial organization on its nuclear viability. The research method is quantitative and descriptive-exploratory. The study area was Karaj metropolis and its main nuclei. The statistical population of this study is citizens living in the sub-nucleus of Karaj. The sample size was 378persons. The data used in this study were collected through library and field research. Data were analyzed using spatial statistics, spatial arrangement, and T-test and Friedman test. The results show that the Karaj metropolitan organization and spatial structure are interconnected and connected to some of the major routes, forming sub-nuclei away from the core and thus transferring the functional and service applications from the center to be the peripheral nucleus. This has affected the viability of the core. Decrease in biodiversity has occurred in different physical, social, economic and environmental dimensions that have affected the environmental and economic aspects less than the other two dimensions, so it can be concluded that the Karaj Spatial Organization has an impact on its viability.
Dr Elham Mobarak Hassan, Dr Ebrahim Fatahi, Dr Abass Ranjbar Saadat Abadi, Dr Nasim Hossein Hamzeh,
Volume 23, Issue 71 (12-2023)
Abstract
The Great Khorasan in northeast Iran has a variety of surface structures and plains and high peaks, but due to its vicinity to the deserts of Afghanistan and Turkmenistan, it is affected by dust all the time, especially in summer. The purpose of this study was to simulate summer dust in this region by RegCM model. For this purpose, during the period 2000 to 2017, three extreme dust events were selected. The satellite image used to confirmed dust mass presence and then the synoptic structure was analyzed. Finally, the simulation results of RegCM 4.6 model were compared with the observational data including the horizontal visibility and aerosol optical depth (AOD) of Aqua satellite. The synoptic analysis showed that during the summer, low thermal pressures form in the southern Afghanistan and high pressure in the north. This structure lead to the development of north and northeast winds with speeds of 12 to 21 m / s and dust emission on the eastern border of Iran and western Afghanistan. Investigation of RegCM accuracy done by visibility, Aquas’s AOD showed that model performance in South Khorasan is better as Razavi Khorasan. The highest correlation coefficients of AOD of model and horizontal visibility were obtained at Khorasan central stations including Gonabad, Ferdows, Nahaband and Ghaen at -0.82, -0.77 and -0.44 respectively. RegCM model performed a better dust simulation in severe dust with a horizontal visibility down to less than 1000 m, high continuity and horizontal extension. Overall, the RegCM model underestimates the AOD value for the Aqua satellite algorithm.
