Showing 175 results for Mohammad
Esmat Khan Mohammadi, Rahim Sarvar, Alireza Estalaji,
Volume 0, Issue 0 (3-1921)
Abstract
Today, the accelerating trend of urbanization, the lack of guidance and urban management, national and regional inequalities, and differences in the socio-economic base of individuals have led to the growth and expansion of informal housing. Due to this situation, informal housing has been expanding in Tehran's metropolitan area. The present study seeks to find key factors affecting informal housing in the study area and also to determine the relationships between criteria through structural-interpretive modeling (ISM). Are; Which is applied in terms of the nature of the application and in terms of the combined method (quantitative and qualitative) and in terms of the inductive research approach In this method, a questionnaire tool was used and in order to analyze the relationships and present their structural model, the interpretive structural modeling method was used, The results of MICMAC analysis and the classification of key factors in the four matrix clusters It shows that the factors of economic growth, redistributive policies, decentralization and transfer of authority, regional equilibrium policies, revision of development and sanctions laws and regulations and its effects are in the fourth cluster,which are in fact variables of research. In fact, key variables are research, and the only factor in housing policies is the cluster of link variables, which will guide other factors, and change will affect the entire system.
Farzad Shirzad, Mr Bohlol Alijani, Mehry Akbary, Mohammad Saligheh,
Volume 0, Issue 0 (3-1921)
Abstract
Climate change and global warming are very important issues of the present century. Climate change process, especially temperature and precipitation changes, the most important issue is environmental science. Climate change means a change in the long-term average. Iran is located in the subtropical high pressure zone in arid and semi-arid regions and the Hyrcanian forest is a green area between the Caspian Sea and the Alborz mountain range. At the 43rd UNESCO Summit, the Hyrcanian forests were registered as the second natural heritage of Iran. Beech is one of the most important tree species and the most industrial species of Hyrcanian forests It accounts for about 18 percent of the northern forest volume (from Astara to Gorgan with a life span of about 250 years). The study area is located in the Shanderman basin in western Guilan province. In this research using tree dendroclimatology, Use of vegetative width of beech tree rings, Weather station statistics located in the study area, And Mann-Kendall nonparametric statistical method, To Investigate Climate Change Trend on Growth Time Series and Pearson Statistical Method, in order to evaluate the correlation of diameter growth of beech tree rings with climate variables in the region, an attempt was made. Results of time series of beech tree growth rings over 202 years. Using the nonparametric method Mann- Kendall showed, Changes in growth rings of beech trees have a downward and negative trend, at level 5 %, it was significant. Temperature Minimum, Average, Maximum, and Evaporation during the growing season, there was an upward trend and Annual precipitation there was a downward trend. Using the Pearson method Fit correlation of growth ring diameter with temperature, For the average monthly in February and the average minimum temperature in July, August and September and Negative correlation, for average maximum temperature in February, July, August and September at 95% level, it was significant and precipitation in June, the correlation was 95% positive and significant.
Nahid Bagheri, Mohammad Mohammad, Ezatollah Mafi,
Volume 0, Issue 0 (3-1921)
Abstract
From the time of human life until now, disasters have had a negative impact on human life; In response, individuals and communities are trying to mitigate the consequences of these disasters and establish scales to assess the initial effects; Also respond to the post-disaster needs and return to baseline. To address these challenges and, as a result, improve the quality of life in cities and metropolises, the need for long-term planning and decision-making in solving these problems is more necessary than ever. Therefore, dealing with new urban theories, each with the aim of solving urban problems, improving the quality and quantity of life of citizens in cities, improving the quality of the city environment, city management, advancing the city to become more desirable, and so on. , Is more important than ever. In recent decades, to solve these challenges and reduce its effects on metropolises and large cities, various solutions and perspectives have been proposed, one of which is to pay attention to the concept of resilient city. The present study is descriptive. - It is analytical and practical in terms of purpose. The statistical population of this study consisted of experts and professors familiar with the topics of the city. 35 university professors and experts in the field of research determined the sample size intended to complete the questionnaire. The results of this study showed that the criterion of physical characteristics of tissue with the highest D-R value (0.672) is at the top of the chart and shows that this criterion is the most effective criterion. Also, based on the calculated D + R value, the building quality criterion is the most important criterion. Also, the urban infrastructure criterion was considered as the most influential criterion due to the fact that it has the lowest D-R value.
Rastegar Mohammadi, Mohammad Saligheh, Mohammad Hossein Naserzadeh, Mehri Akbari,
Volume 0, Issue 0 (3-1921)
Abstract
Extratropical cyclones according to the frequency, duration, and intensity, the major cause of mid-and high-latitude precipitation across the Mediterranean during winter and autumn. For this research using network data of ECMWF climatic variables with 6-hour time resolution and 0.25 × 0.25 spatial resolution from1979-2016 and were used of 4 Basin stations precipitation data from the Asfezari database from 1979-2016. The results showed that the first pattern is the Mediterranean trough pattern which has the highest frequency of 42%. In this pattern, the low-level due to the presence of a high-level that acts as a barrier have caused the deepening of the Mediterranean low-level and its axis extends to the Red Sea, and due to the collision of low-level and high-level on the region, instability is intensified and has caused the most rainfall among the patterns. In contrast to the first pattern, The fourth pattern has the lowest frequency of 10% Which is the trough pattern of western winds which is located on the Caspian Sea but due to high-level in the south of the region has prevented the entry of low-level and is located in the northern part of the study area due to this, the isobar in the north of the region have become orbital as a result, fewer cyclones enter the area, resulting in less rainfall between patterns. The results also showed that the frequency of cold-core cyclones was 60% in winter and 40% in autumn, but the frequency of hot core cyclones was 62% in winter and 38% in autumn, which in winter, the frequency of hot core cyclones has increased compared to cold-core cyclones, while in the fall the frequency of hot-core cyclones has decreased compared to cold-core. In the last decade, both the frequency of occurrence of cyclones and their intensity has decreased compared to the last two decades. In terms of cyclogenesis places, the western part of the study area has always been active, And with the onset of the cold season from autumn to winter, cyclogeneses places are gradually becoming more active.
Mohammad Saghebi, Ezatollah Mafi, Mehdi Watanparast,
Volume 0, Issue 0 (3-1921)
Abstract
Nowadays, addressing approaches such as livability for today's cities as concepts that play an important role in reducing social, economic and environmental problems of cities is an inevitable necessity. In fact, livability is a concept with all angles and mental and objective dimensions Is concerned with human beings and seeks to create a healthier and more livable urban environment for current citizens of future generations; Therefore, livability is a new concept and approach in the paradigm of sustainable urban development, which some consider one of the greatest ideas of urban planning in modern times. In livable city, the goal is not only to meet the physical needs of urban society, but also to create a sense of citizen satisfaction According to this, the main purpose of this research is an analysis of urban livability in Bojnourd with emphasis on security index.
The purpose of the present study is applied and in terms of method: descriptive-analytical. Using GIS software, maps related to the status of each of the objective sub-indicators based on Bojnourd city police stations have been drawn. For mental indicators that have 8 items, a questionnaire The sample size in the whole city of Bojnourd is 383 people. The results of this study show that police station area 13 of Bojnourd (in region one) is the best area in terms of security index. The worst area in terms of security is related to police station area 12 (area two) in terms of index. It is security.
Dr Hassan Kharajpour, Dr Zahra Hejazizadeh, Dr Bohloul Alijani, Dr Mohammad Hossein Nasserzadeh,
Volume 0, Issue 0 (3-1921)
Abstract
Considering the undeniable impact of agricultural plants on climatic and regional changes, it seems necessary to conduct regional research to understand the reaction of each agricultural plant in different stages of growth in relation to weather elements. If the temperature of the air along with the warm cloud is lower or higher than a certain threshold, its development will stop. Between the two limits, there is an optimal temperature where the plant grows the fastest. Temperature and clouds are both the most important climatic elements in agriculture. Both climatic parameters together cause stress in wheat and lower the productivity of the product. Considering the strategic nature of wheat, in order to increase the level of production, in the present research, while taking advantage of the experiences and methods and models used in foreign and domestic researches, it was practical in Kermanshah province due to the extent of the land under wheat cultivation and The significant amount of production, which has a special place in this field at the level of the country, the determination of the statistical threshold and the synoptic analysis of warem cloud temperatures on the performance of the wheat crop are investigated. According to the investigations and consultations with agricultural engineers, the maximum temperature along with cloudy days causes the phenomenon of greenhouse and excessive heat, which causes the fall of flowers, rot, sterility of pollen grains, fruit reduction, Premature aging and poverty become seeds, and this phenomenon occurs mostly in the months of May and June.
Sedigheh Mohammad Panah, Hamidreza Varesi, Masoud Taghavei,
Volume 0, Issue 0 (3-1921)
Abstract
The use of structural analysis of development drivers helps planning to better understand the development situation of the provinces and improves the regional balance during decision making. For this purpose, the ten cities of Ilam province were examined in terms of combined development indicators in the form of 44 indicators. This research is an applied study in terms of targeting and in terms of methodology, it has been done in a "descriptive-analytical" way and is explanatory based on new methods of futurology. Theoretical data have been prepared by documentary method and experimental data by survey method. The development drives has been extracted from the documentary method and environmental scanning and experimental data based on the survey method based on the Delphi method. In data processing, structural interaction analysis method has been used in MIC MAC software. Findings in terms of interaction analysis indicate the dispersion of propulsive forces in a complex and intermediate situation of impact and effectiveness; the drivers clustering system indicates the focus of effective and regulatory drivers. Among the 44 driving forces of development, the effective drivers of development are the borders of Ilam province and the manner of managers' decisions. Research results show that development in Ilam province is not only unbalanced, but the imbalance trend applied towards more inequality and only by better and more comprehensive planning can be partially eliminated inequalities.
Abolfazl Meshkini, Mohammad Reza Bahrami,
Volume 0, Issue 0 (3-1921)
Abstract
In the creation of urban space, there is always an exchange of ideas about what the space is now and how it should exist, by those who live in that place. So improvement in its harsh reality is realized in some of their thoughts in the form of a physical change in the current environment - and urban regeneration is one such form. Considering the increase in the number of urban regeneration projects in recent decades, it is very important to pay attention to the social dimensions in it. On this basis, social capital, as one of the social potentials of the neighborhood, is a concept that has gained special importance in regeneration. Considering the necessity of the subject, this research has analyzed the role of social capital on the regeneration of urban neighborhoods. The applied research method is descriptive-analytical in nature and the main goal of this research is to analyze the role of social capital in the regeneration of Islamabad Karaj neighborhood among the residents of the neighborhood. In this regard, the data collection in the theoretical part was based on the documentary method and in the practical part, the survey was based on the questionnaire. The statistical population of this research is made up of people over 15 years of age living in a neighborhood of over 25,000 people using a simple random sampling method, so a sample of 410 people was selected from this population using Cochran's formula. For data analysis, Spearman's correlation coefficient and multiple linear regression were used using spss software. The results showed a strong correlation between social capital and urban regeneration in Karaj neighborhood of Islamabad. The implications of this research on the relationship between social capital and urban regeneration increase the need to pay attention to the components of social capital and adopt policies to maintain and promote it in order to ensure successful urban regeneration in the neighborhood of Islamabad Karaj.
- Mohammad Reza Ghorbani Param, - Pouyan Shahabian, - Vahid Dinarani, - Ronak Najafi,
Volume 0, Issue 0 (3-1921)
Abstract
The quality of the urban environment is one of the important indicators of the development of any city. In this regard, the type of pattern that can be used in cities can have a great impact that biophilic urban planning is one of the most important patterns due to its relationship and centrality with nature. The purpose of this study is to explain the environmental quality criteria of Tehran according to the components of biophilic urban planning. The research method is descriptive-analytical and based on data collection through survey method. The research tool was a questionnaire whose validity was confirmed by the elite community and its reliability was confirmed by Cronbach's alpha coefficient greater than 0.70. The statistical population of the study also consists of urban experts and specialists, including academics and experts in Tehran. Due to the lack of statistics in this area, coronary and cost constraints, 120 experts were selected as the sample size. The results showed that the structural-functional, content and physical-spatial indicators of the quality of Tehran's urban environment based on biophilic urban planning were significant at a level of less than 0.05. The study of the mean and significant direction indicates the weakness of these indicators and lack of attention to biophilic urban planning in the planning of this city. Also, the results of structural equation modeling confirmed that the structural-functional, content and physical-spatial indices of biophilic urban planning can be effective in improving the quality of Tehran's urban environment. . Therefore, biophilic urban planning has not been emphasized in the planning model of Tehran, but the results indicate their effectiveness in improving the quality of the city's environment if used.
Tahereh Karimi, Amir Karam, Parviz Zairean Firuzabadi, Seyyed Mohammad Tavakkoli Sabour,
Volume 0, Issue 0 (3-1921)
Abstract
Abstract
Every year slope hazards and landslides cause significant damage in the mountainous areas of Iran, including the eastern Alamut region in Qazvin province. Recently, radar data has been widely used to detect ground surface movements, slope slow motions, and active landslides. In the present study, using the Sentinel 1A satellite descending data in the period from 2018 to 2020, with the Small Baseline Subset (SBaS-InSAR) and also with the digital elevation model (DEM) difference methods, slope motions and Earth surface displacements have been extracted to provide the important goal of detecting new and active landslides and updating the landslide map to predict landslide risk. Results show that in the SBaS model, which was validated with GPS data, field visits and Google Earth images, accuracy was relatively good (AUC = 0.78), and the average annual movement during this period was estimated at -48.6 to 40.2 mm and fourteen landslide zones in the region, are identified among which some of the previous landslides are still active. To detect the landslide that occurred in Khobkuh on April 3rd, 2020, DEM difference model estimated the surface changes between -1.62 to 2.75 meters and differential interferometry model estimated the displacement rate in this area from -25 to 70 mm. These methods have many advantages for estimating the Earth surface displacement, subsidence and landslides, determining vulnerable areas in mountainous areas and reducing financial and human losses.
Tahereh Karimi, Amir Karam, Parviz Zeaiean Firuzabadi, Seyyed Mohammad Tavakkoli Sabour,
Volume 0, Issue 0 (3-1921)
Abstract
Abstract
The catchment area of Alamut River in Qazvin province is witnessing numerous landslide hazards and landslides every year, which cause significant economic and sometimes life-threatening losses. Diagnosing the unstable areas of slopes through soil texture characteristics is a difficult task due to the difficulties of obtaining soil samples in mountainous areas. For this reason, in the present study, by using Sentinel A1 radar data, by determining the percentage of clay and sand in the soil, the soil texture map at the depths of 10, 60, 100 and 200 cm with two random forest (RF) and support vector machine (SVM) algorithms was produced in the eastern Alamut region, which was verified with soil profile samples. The results indicated that the Kappa index was more accurate in the RF model at three depths of 10, 60 and 100 cm. Then, by extracting the soil moisture map from Sentinel 2 data, at the same time as examining the internal friction angle of the types of soils in the region, comparing the slope and profile of the slopes and the shape of the convex (divergent) and concave (convergent) slopes, the unstable areas of slope movements, RF and SVM models were specified and validated with GPS data, field visits and Google Earth. Research findings show that the instability map resulting from the RF model has a higher accuracy (AUC=0.93) than the instability map resulting from the SVM model (AUC=0.90) and there is more instability in areas with medium to high slope and with soil texture of sandy clay loam and sandy loam. . This method has many advantages in preparing the soil texture map, determining the unstable areas of the slopes against mass movements and landslides, determining the vulnerable areas in mountainous areas and reducing financial and human losses.
Miss Sorayya Derikvand, Dr Behrooz Nasiri, Dr Hooshang Ghaemi, Dr Mostafa Karampoor, Dr Mohammad Moradi,
Volume 0, Issue 0 (3-1921)
Abstract
sudden stratospheric warming has an obvious effect on the Earth's surface climate. In this research, the changes in precipitation during the occurrence of this phenomenon have been investigated. For this purpose, after revealing the warmings that occurred during the studied period (1986-2020), 18 warmings were identified. The 5th decile and 9th decile of precipitation were calculated for the precipitation data of 117 stations. And the size of the difference from the normal rainfall was checked in two ways. First, the precipitation at the time of warming was compared with the long-term average, and then the trend of changes in precipitation at three times before thewarming, at the same time as the warming, and after the warming was finished. Finally, these results were obtained. Warmings according to the month in which they occur; They have a different effect on the amount of precipitation. In the sudden stratospheric warming that occurred in December, January and February, the northwest experiences the most rainfall changes and is above normal, and the probability of rainfall above the 9th decile increases up to 65%. Western and southwestern regions also have higher than average rainfall and the probability of heavy rainfall is high. Precipitation on the shores of the Caspian Sea shows an inverse relationship with sudden stratospheric warming, so in all the investigations of this research, the lack of precipitation at the time of warming in these areas is significant. Southern regions have less than normal rainfall in all sudden stratospheric warming events. The center of Iran has higher than average rainfall in the sudden stratospheric warming months of March. Eastern Iran also has heavy rains compared to normal during the sudden stratospheric warming months of March.
Mis Ameneh Alibakhshi, Dr Mohammadreza Pourmohammadi, Dr Rasoul Ghorbani,
Volume 0, Issue 0 (3-1921)
Abstract
In recent decades, one of the main challenges in regional development studies is trying to understand the economic and cultural differences between the national and regional levels, so that the obstacles facing regional development can be removed. One of the systems that plays an important role in the development of regions is the regional innovation system. For this purpose, the aim of the current research is to identify the key drivers effective on regional innovation in the metropolis of Tabriz. In this regard, the current research is applied in terms of purpose and descriptive-analytical in terms of nature. In order to collect the required information, both library and field methods have been used. The statistical population of the research includes 32 qualified people in the industry, university and government sectors who were selected by purposeful sampling. Mic Mac software was also used for data analysis. The findings of the research show that out of a total of 71 influential factors, 13 factors include the appropriate culture of productivity, laws and regulations, the existence of a teamwork culture between activists and established industrial units, information and communication technology infrastructure, sufficient funding for university research infrastructure, and higher education. patent programs, higher education policy, performance evaluation and reward system, financial support, special and flexible tax system for research and development, the existence of joint research centers between universities and industry and the level of interaction and cooperation between universities and industry, a key role in innovation They have an area of Tabriz metropolis.
Majid Goodarzi, Ali Ashkboos, Behnam Mohammadi,
Volume 0, Issue 0 (3-1921)
Abstract
The intermediate development approach suggests that empty lands and the inner destructive structure of cities should be targeted for development instead of taking the peripheral lands of the cities under construction. Considering this importance, in this article, an attempt has been made to identify and prioritize the obstacles to the intermediate development of Zabol using Chang’s technique. The present applied study employed a descriptive-analytical research method and library and survey research (field studies) data collection techniques. The statistical population for identifying the obstacles of intermediate development consisted of all the residents of Zabol city in 2023. The sample size was calculated as 384 via Cochran’s formula. The purposive sampling method was employed to collect the data. Cronbach’s alpha coefficient calculated the research instrument’s reliability as 0.80. The obstacles were identified using a sample t-test in SPSS, and the upcoming obstacles were prioritized. The required data were collected from the existing facts of the city and through a questionnaire distributed among 20 related experts. Then, data and information were analyzed using Chang’s technique (AHP-FUZZY). The research results showed that the most important obstacle to implementing the intermediate development plan of Zabol city is the economic index, with a final weight of 483.
Hosein Shamsi, Rahmat Mohammadzadeh,
Volume 0, Issue 0 (3-1921)
Abstract
Lefebvre's theory has received much attention in the field of space production, and its importance is especially in the fact that it is systematically integrated in the categories of city and space as a comprehensive and comprehensible social theory.
The traditional planning of land use is completely abstract and formal and devoid of perceptual and meaningful components, but Lefouri's trialectic approach is not like this and consists of three virtues (spatial practice-spatial representation and representational space) that are in communication with each other and collaboratively and at the same time in the moment. They form, produce a whole.This research has a descriptive and analytical method, and in terms of its purpose, it is fundamental. The changes caused by the arrival of new paradigms in the approaches of urban planning and urban design, which assigns a different nature to the strategic system of urban development changes, and on the other hand, new attention to space and finding the concept of living space to be important, it seems that Lefebvre's trialectic approach is contrary to traditional user planning. The land values the everyday space and lived experience of the residents and can create spaces that increase the sense of place and sense of belonging of the residents to their living space.The review of the concepts shows that the concept of lived space (abstract-concrete space) was influenced by different approaches of the philosophy of science (interpretative and critical) and now it is witnessing an approach change (paradigm), which can show social transformations. This study shows that space-place (living space or space-love) is, unlike the previous definition of space based on positivist (mental and perceptual), abstract and generalist approaches, mainly a demarcated area of space that has physical-concrete characteristics and It is formed and filled with meaning through human experience.
Phd Mohammad Mohammadi,
Volume 0, Issue 0 (3-1921)
Abstract
Today, energy consumption plays a decisive role in the qualitative and quantitative development of human life. One of the energy sources is in line with the development and economic prosperity as well as acquisition of climate comfort in natural gas. This source of energy supply, especially in cold areas of the country as well as to provide thermal comfort is required to proper management. Good management of this fossil energy sources is through awareness and forecasts of demand rate of that path. For this reason, demand for natural gas in Zanjan city was studied and modeled as one of the cold cities in Iran. Two groups of data (weather elements and natural gas consumption) for a period of 9 years (2013-2021) on a daily scale have been used for performing this study. CurveExpert software and regression method (regression) were used in order to modeling the demand for natural gas in the city. Based on the most graceful pattern, temperature element was selected as the only independent variable in selective pattern. Polynomial regression with a correlation coefficient of 0.94 (coefficient of determination 89.03 percent) was selected to the final model. The percentage increase in natural gas consumption per one degree decrease in temperature, from 22 to 16 degrees, the highest percentage increase and from zero to -5 degrees, the lowest percentage increase per one degree decrease in temperature. The turning point and the beginning of problems related to the lack of natural gas in Zanjan city was determined to be below minus 7 degrees.
Mis Zahra Asgari Gandomani, Mr Hamid Roodbari, Mr Yaghoob Mohammadi,
Volume 0, Issue 0 (3-1921)
Abstract
Many sports consumers are concerned about environmental issues and have expressed interest in buying green products. However, the actual sale of green products is still not as expected. For this reason, the purpose of this study is to investigate the effect of environmental factors (attitude, concern and sense of environmental responsibility) on the purchase intention of environmentally friendly sports consumers. The present survey study collected information from 384 Iranian students using a seven-point Likert electronic questionnaire with 27 questions. The samples were selected using simple random sampling method. A total of 390 questionnaires were returned, of which 384 were approved. To analyze the data, PLS software was used for the reliability and validity of the model and to test the hypotheses of the structural model. The results showed that environmental attitude is an important driver of consumers' green purchasing behavior. Also, a statistically significant relationship between environmental responsibility and green purchasing behavior was obtained. But there was no statistically significant relationship between environmental concerns and green purchasing behavior. In addition, the relationship between individual green values with environmental attitude, environmental concerns, environmental responsibility and green purchasing behavior was statistically insignificant. For this purpose, companies can create a suitable image of environmental responsibility for their products in the minds of customers through appropriate strategies in the branding of their products, which makes them benefit from the support of customers who want to buy environmentally friendly products.
Dr Mahdi Charaghi, Dr Hossein Tahmasebi Moghaddam, Master's Student Mohammad Reza, Nemati, Phd Saeed Nasiri Zare,
Volume 0, Issue 0 (3-1921)
Abstract
Undoubtedly, the development of tourism in any region requires a precise identification of the area and the provision of facilities and services needed by tourists, which is essential for the purpose of planning at all levels in order to achieve the successful development of tourism. This research deals with the pathology of service provision and prioritization of tourist destinations in terms of tourism potential in Zanjan province. The research was a combination of qualitative and quantitative, which was the method of collecting information in the form of interviews and questionnaires. In order to analyze the interviews from MaxQuda, the hierarchical analysis model was used to evaluate the criteria and the geographic model was used for the geographical distribution of tourist destinations. According to the findings of the research, Zanjan province, despite having suitable capacities for tourism, suffers from many problems such as lack of facilities, instability in policies to improve the quality of tourism services, and lack of management and planning in tourism development, and has not yet enjoyed proper progress in this field. The low general level of services and inconsistency in planning and different views on tourism are the two main problems of the tourism services sector in Zanjan province. But according to the geographical distribution, tourist destinations: Soltanieh dome, gen chimneys, Angoran mine, Oljaito ecotourism resort, Soltanieh ecotourist resort, boutique hotel, Zulfaqari mansion, El Daghi, Seyed Mohammad bridge, Zanjan Jame Mosque, Khedevi house, colorful mountains in the first cluster This means that the tourist destinations in question are surrounded by high capabilities and more population, which should be placed as priority areas in the planning and development of services.
Zahra Hedjazizadeh, Sayyed Mohammad Hosseini, Ali Reza , Shokofe Layeghi,
Volume 0, Issue 0 (3-1921)
Abstract
Drought is a natural hazard that annually causes significant economic, social, environmental, and life-threatening damage in vast areas of the Earth. The damages caused by this phenomenon are intangible but very extensive and costly, which, if necessary, remote sensing techniques can be a useful tool in monitoring drought due to high temporal accuracy, wide spectral coverage, ease of access, no need for atmospheric correction and ground referencing. In recent years, the province of Hamedan has faced many problems due to frequent droughts. Therefore, the present study focused on investigating and monitoring drought in Hamedan province using the Temperature Condition index and its impact on the vegetation cover of the province using Advanced Very High Resolution Radiometer (AVHRR) and National Oceanic and Atmospheric Administration (NOAA) remote sensing data. First, the relevant data was extracted from the Nova star database, and finally, the spatiotemporal behavior of the vegetation cover drought index was examined on 1528 pixels in Hamedan province. The spatial resolution of the data used in this study is 4 kilometers. First, the relevant data were extracted from the Navstar database and ultimately, the spatiotemporal behavior of the drought index and vegetation cover was examined. The results indicate that drought has significantly increased the vegetation cover of Hamedan province based on remote sensing data. Kendall's coefficients indicate the presence of decreasing trends in vegetation cover at a 95 Percent confidence level. Only in May, June, and December has there been a slight decrease in vegetation cover within the extent of drought in the province. The spatial behavior analysis of the drought index on vegetation cover showed that February, March, as well as April have experienced more severe droughts within Hamedan province.
Sharifeh Zarei, Dr. Bohloul Alijani, Dr. Zahra Hejazizadeh, Dr. Bakhtiar Mohammadi,
Volume 0, Issue 0 (3-1921)
Abstract
In this research, the most important synoptic patterns of widespread snowfall in the eastern half of Iran have been investigated. For this purpose, the current weather code data and snow depth of synoptic stations in the eastern half of the country during the statistical period of 1371-1400, for the months of October to March, were received from the country's meteorological organization. In order to investigate widespread snowfall, the days when more than 70% of the studied area saw snowfall at the same time were extracted as a widespread day. In order to perform synoptic-dynamic analysis of widespread snowfall in the eastern half of Iran, the classification method using cluster analysis was used and the maps of the representative days including atmospheric temperature, moisture flux, geopotential height, vorticity, front formation, jet stream, omega index and orbital and meridian wind data were drawn. Trend analysis was also performed using the Mann-Kendall test. The results showed that 3 patterns justify the snow cover in the studied area. These patterns are: high pressure in Siberia and central Europe-low pressure in eastern Iran, high pressure in western Iran-low pressure in Sudan, high pressure in central Europe-low pressure in eastern Iran and Afghanistan. In all the patterns in the middle of the atmosphere, the intensification of the meridian currents of the western winds along with the formation of high pressure and low-pressure centers has caused blocking in the path of the western currents and has provided the conditions for the ascent of the air. The concentration of the negative omega field and the relative positive advection, along with the location of the northeastern region of Iran in the left half of the outlet of the Subtropical Jet, have caused severe instabilities and widespread snowfall in the region. Also, the results showed that despite the absence of a trend in the number of snow days in the northeast of Iran, the number of snow days has decreased over time.
