Showing 681 results for Type of Study: Research
Ms. Aida Faroghi, Professor Manuchehr Farajzadeh, ,
Volume 0, Issue 0 (3-1921)
Abstract
In this research, the frequency of merging of the polar-front and subtropical jet streams and its effect on the amount of precipitation received from the atmospheric pattern in western Iran during the 10-year statistical period of 2010-2019 was investigated. Then, by coding in Grads, the maps of jet stream level 300 hPa were drawn with a time interval of 6 hours. During the statistical period, these two jet streams merged along their axis. By examining the frequency of the merging of two jet streams, it was found that until 2015, the frequency of the merging of two jet streams in December was an increasing trend and in 2016 and 2017, there was a decreasing trend. It has increased again in 2018 and 2019. In all cases, the merging of two jet streams has not resulted in heavy precipitation events (December 2011, 2014 and 2017). So, considering the heavy rainfall of 110 mm from Dehloran station, the date of 12th to 15th of December was chosen to analyze and understand the system that led to the occurrence of rainfall. From December 12 to 15, 2010, the decrease in air temperature over Europe and Southwest Asia led to a large meridional movement of the polar-front jet stream, which resulted in merging with the subtropical monsoon. On the 12th of December 2010, along with the medicalization of the polar-front jet stream and its penetration into the tropical regions, its velocity core merged with the core of the subtropical jet stream over the northern Arabian Peninsula, the Red Sea and northeastern Africa. The merging of these two jet streams has led to the vertical expansion of the jet to lower levels, and in the middle level of the atmosphere, very low meridional movement is observed. As a result, the Sudan low moves to higher latitudes and merges with the Mediterranean low pressure.
Seyd Fateme Hashemi, Ali Shahnazari,
Volume 0, Issue 0 (3-1921)
Abstract
Huge floods carrying enormous amounts of transported silt occur annually in the Talar River's catchment area in the province of Mazandaran. In order to investigate the sediment transport from the specified watershed, samples were collected at five different time intervals, specifically on May 22nd, 2018; May 20th, 2018; May 17th, 2018; and May 16th, 2018. The study focused on two dates, 17.11 and 5.11, and a specific stretch of land measuring 16.75 km between Darya Malakala-Najjarkala and Arab Roshan, located outside the urban area. The purpose was to analyse the patterns of sedimentation and erosion throughout a five-year period (2016-2021) using the HEC-RAS model. Inspected. The sediment transport and volume of sediment were analysed and studied based on the long-term statistics of the Kiakla hydrometric station. This analysis focused on flood conditions with return periods of 2, 10, 25, 50, and 100 years for the watershed of the station. The findings indicate that the cumulative sediment input at the start of the simulation period is 0.9 million tonnes lower than the total sediment at the end of the period. Additionally, the river is susceptible to erosion in the majority of situations. Furthermore, during the initial period (22.4-24.7), the sediment's mean height measures 11 cm, with a substantial sedimentation of 6 million tonnes. The deposition during the second period (2018-05-20) amounts to roughly 1 million tonnes. In the third quarter, there is a relatively consistent pattern. During the fourth phase, the erosion conditions, in terms of both depth and volume, are unsuitable for harvesting. During the fifth phase, which lasted from 11.5 to 16.75, the erosion amounted to approximately 8.3 million tonnes. The erosion height change in the fifth interval ranges from 10 to 20 cm. All distances are measured in km from the sea. Under such circumstances, sediment removal is unfeasible, but it is advisable to consider flood management and river engineering measures.
Dr Saeedeh Fakhari,
Volume 0, Issue 0 (3-1921)
Abstract
Investigating the awareness of the local community towards the development of ecotourism is very important and necessary for future planning. Ecotourism in any region affects the lifestyle of local people and their economic-cultural conditions. On the other hand, ecotourists are also influenced by the culture of the host society and its values. Therefore, this study examines the local community's awareness of supporting ecotourism development in Damavand City. Due to the preservation of unique biological diversity, climatic conditions, and the frequent visits of tourists and ecotourists to this region, the local community needs to know about ecotourism, which made this research necessary. The target community of this study is the local community of residents of Damavand city. Therefore, using Cochran's formula, the sample size was estimated to be 384 people. The data was collected through a researcher-made questionnaire, which was used to determine its validity, in addition to seeking opinions from experts (face validity), convergent validity was used. To calculate its reliability, Cronbach's alpha method and composite reliability were used. The results of the inferential statistics that were conducted using confirmatory factor analysis (Smart PLS software) showed that the four components of the research (local community awareness, economic poverty, cultural poverty, and ecotourism development) have homogeneity and reliability, and the awareness of the local community It has a significant relationship on the development of ecotourism with the mediating role of cultural poverty with the test statistic value of 4.195 and economic poverty with the test statistic value of 5.397. The results showed that the awareness of the local community on the development of ecotourism with the test statistic value of 2.032 indicates the low level of awareness of the local community towards the development of ecotourism
Mrs Reyhane Salehabadi, Dr Mohammadreza Hafez Nia,
Volume 0, Issue 0 (3-1921)
Abstract
After the victory of the Islamic revolution, a new form of attitude towards science and technology was formed in Iran. This scientific discourse was directly influenced by the Islamic revolution and Islamic ideology and formulated new values and goals for the development of science and technology. After the revolution, since the statesmen considered science and technology as one of the key factors for the development and excellence of the society, they formed scientific policies and plans in order to realize the revolutionary and Islamic goals. This attitude towards science and technology in Iran during that period had a significant impact on the country's scientific and technological development. Considering the fact that the Islamic Republic of Iran has been at the helm of scientific leadership in the region after 1357, Iran and its role in the development of scientific power in post-revolution governments. In order to achieve this goal, the descriptive-analytical method and reliable statistics in domestic and foreign sources were used. The findings of the research showed that the type of discourse in different governments includes focusing on industrialization through the substitution of imports and capital resources (1360-1368), modernization and institutionalism and focusing on advanced technologies (1376-1368), focusing on technologies advanced, innovation and export development, and social justice mainly relying on knowledge industries (1384-1376), focusing on the transition of the industry towards knowledge-based innovation in the economy (1384-1392) and emphasizing the increase of international cooperation with an emphasis on identity and Rationality was in compilation and implementation (1392-1400). The results of the research show that in each period, according to the dominant discourse, measures such as the development of higher education and scientific research, the establishment of universities and research centers, and the creation of domestic and international scientific networks can be mentioned.
Faeze Shoja, Salimeh Sadeghi, Shamsipour,
Volume 0, Issue 0 (3-1921)
Abstract
The aim of this research is to evaluate the heat mitigation index (HMI) in the Tehran metropolitan area using the Urban Cooling Model(UCM)approach in a spatial framework. UCM produces maps of the Heat Mitigation Index. This index estimates the cooling potential of urban green spaces in a given location, taking into account various parameters such as evapotranspiration, tree shading, albedo, rural reference air temperature, urban heat island intensity, air temperature maximum blending, and maximum cooling distance. The assessment of environmental factors influencing the UCM in the study area revealed that the urban heat island effect was least intense in regions 1, 22, and the northern parts of region 4 of Tehran municipality, where there are scattered trees, shrubs, open low-rise buildings, and water bodies. The temperature differential between the city and the suburbs ranged from 0 to 1.3 degrees Celsius. However, the study area's central parts showed the highest intensity of the urban heat island, particularly in regions 21, 13, and 14. These regions have a dense and compact texture and an expansion of impervious surfaces, resulting in the lowest values of the evapotranspiration index and albedo.Based on these parameters, the study area's HMI index showed that the cooling capacity varies from 0.08 in the central parts of the city to 0.9 in areas affected by green spaces and water bodies. The maximum cooling capacity index is concentrated in areas with dense and scattered tree cover in the region. On average, these areas have been able to neutralise 2.48 degrees Celsius of the urban heat island effect with a cooling capacity of 63%. The methodology employed in this research can be used as a reference for urban designers in integrating urban cooling approaches and heat island mitigation strategies in urban planning and design.
Mohammad Radman, Mohammad Saligheh, Mohammad Hossein Naserzadeh,
Volume 0, Issue 0 (3-1921)
Abstract
In order to comprehend the water flow characteristics and variations of the Karun River, we examined the Zaz, Bazoft, and Beshar sub-basins from its main branches. The reason for choosing these basins was the proximity to the catchment centers of the Middle Zagros and their location upstream of the dams.
Iran Water Resources Management Company provided all the required data (from the water year
1356-57 to 1395-96), and we analyzed them using Kolmogorov-Smirnov tests, data skewness, skewness, and Pearson correlation. Then, we performed the linear regression test to determine the effect of temperature and precipitation on river discharge, and they conducted the Mann-Kendall test to identify the trend and jump points. The results of the data analysis showed that all of them are in normal conditions, although they have some elongation and skewness. The Pearson correlation test revealed a correlation between meteorological and hydrometric data.
The regression model used shows the changes in precipitation and discharge (unlike temperature and discharge) well. The significance number of all stations in the model is less than 0.05, which shows that the changes that occurred between predictor and dependent variables are significant. We see the high performance of the model in explaining the changes in discharge compared to precipitation. According to the regression charts, the decreasing trend of precipitation and discharge and increasing temperature are clear in all three basins.
The Mann-Kendall test reveals a significant trend of increasing temperature in Bazeft and Bashar basins, a decreasing trend of discharge in Bazeft and Bashar basins, and a decreasing trend of precipitation in Zaz and Bazoft basins.except for the temperature of the Zaz basin, all variables show mutations in mutation basins.
Dr Fatemeh Saffarsabzevar,
Volume 0, Issue 0 (3-1921)
Abstract
One of the most important approaches to increasing security is crime prevention through environmental design that focuses on urban design. The current research aims are to examine the exact environmental conditions that are effective in committing crimes in Tehran's Englebal Street and to provide design solutions to reduce crimes in this place. This study used a combined method to achieve the research goal. For this purpose, in the first part, by using the technique of Placecheck (including field survey and also preparation and completion of experts' checklist and comprehensive checklist), the environmental conditions of the studied area were classified and solutions were presented to reduce the crime in the target site. In the second part of this research, to prioritize the solutions and choose the optimal solution to prevent crime and reduce it in the studied area, the network analysis method (ANP) was used. According to the findings of the present research, Environmental pollution, visual pollution, crowding, and the issue of light and standard lighting at night are the most important environmental factors of crime in Tehran's Enghelab Street. Also, the most optimal solutions to reduce crime and increase security in the studied area are: removing furniture and elements attached to the footpath, legible definitions of activities and uses in illegible points of the space, creating signs and index elements along the route, limiting advertisements and creating standard lighting during the night to carry out activities. Based on the results of the current research, minor changes in the environment can have great effects on reducing crime and increasing security
Atefeh Rezaei Talei, Zahra , Buhlol Alijani, Hematolah Roradeh, Taher Safarrad,
Volume 0, Issue 0 (3-1921)
Abstract
| The role of regional and extra-regional forcings causes changes in the Siberian high-pressure cyclonic circulation every year. In this regard, an attempt was made to investigate the variability of the intensity of the Siberian high pressure in relation to the abnormal winter circulation of the atmosphere. For this purpose, gridded data of sea level pressure, geopotential height, orbital and meridional wind components of Center for Environmental Prediction/Atmospheric Sciences (NCEP/NCAR) between the years until 2020 (December to February) were used. After applying the Siberian high pressure intensity index, the extreme periods of this high pressure in winter were extracted. Next, the development of this system and the systems affecting the Siberian high pressure were investigated using the quantity of relative Vorticity advection. The results showed that during the winter period, the high pressure center of Siberia has undergone changes and has taken on a growing trend between 4 and 6 hectopascals. On the other hand, it was observed that the role of atmospheric systems such as dynamic ridges on the Siberian region along with advection The negative relative humidity, the location of the Siberian region in the east of the ridge, and the formation of omega bands play an important role in strengthening this system, which has caused this high pressure to develop from east to west or north to south. On the other hand, the role of the polar vortex in the cold advections of the region and the displacement towards the equator has caused the Siberian high pressure to sometimes increase by more than 11 hectopascals compared to its long-term average. Finally, it was observed that the atmospheric circulation in mid-latitudes plays a transitional role in the high pressure changes in Siberia and the polar and subpolar currents. |
Dr Mohammad Motamedi Rad, Dr Reza Arjmandzadeh, Dr Ebrahim Amiri, Mr Farzad Amiri,
Volume 0, Issue 0 (3-1921)
Abstract
| The continuation of drought and the simultaneous increase in dependence on underground water sources in the past decades have expanded the range of areas subject to subsidence to many different parts of the country, which results in a lot of damage.In order to reduce the damages caused by land subsidence, it is necessary to have a complete and accurate understanding of this phenomenon. In recent decades, the virtual aperture radar (SAR) interferometric technique has become a common method for measuring subsidence. In this research, field data such as piezometric wells and groundwater drop in the minimum and maximum periods and exploitation wells were used to calculate the amount of discharge in the aquifer using IDW interpolation, aiming at analyzing the time series of the subsidence of the Esfarayen plain. besides, radar data including Sentinel 1 images were used to calculate the subsidence rate in the first 8 months of 2023. The results of the research show that the amount of subsidence in the study basin was from 1 to 12 mm in a period of 8 months and 75.2% of the area of the basin was in the medium critical and very critical zone, which can be recognized based on this. He showed that the Esfrain plain is in a critical state.The most water extraction and subsidence has been related to to south of Sankhasat, south of Kharasha, south of Arg, south of Gazan, Jafarabad Kharaba and Mehdiabad of Kal Beko wells, which are located in the very critical area and require efficient management of groundwater resources in order to control land subsidence. |
Arefe Shabani Eraghi, Seyed Mohammad Zamanzade, Fariba Karami,
Volume 0, Issue 0 (3-1921)
Abstract
Reconstruction of paleoclimate, including environmental temperature, plays a significant role in understanding the current and future climate. The purpose of this research is to investigate the climatic conditions and calculate the ambient temperature of two sediment cores taken in the Jazmozian basin in the Holocene period. Reconstruction of paleotemperature is done by various methods, one of which is using the value of the standardized variation coefficient of oxygen isotope 18 andcarbon-13. In this regard, the analysis method of oxygen isotopes 18 and 16 andcarbon-13 has been used. At the beginning, there were 46 degrees in Jazmurian core number 1. Then there is a decreasing trend of 10 degrees Celsius up to a depth of 175 cm in 8 levels in the region, at a depth of 175 cm there is an increasing trend and a decrease in the next level and then an increasing and constant trend in the next two levels. In Jazmurian number 2, the temperature is 50 degrees at first, then there is a sharp decrease in temperature at the depth of 80-125 degrees. Then the trend is slightly increased (1 degree) and this temperature continues to the depth of 170, after this there is a decrease in temperature again in the last two layers. The amount of carbon-13 in borehole number 1 varies between 0 and 25.6, and in borehole number 2, the amount of this parameter varies between 25.9 and 27.1. In this area, in core number 1, the value of 6 carbon 13 isotope samples is zero, which indicates the absence of carbon 13 isotope in the sediments. In core number 2, the range of changes is not relatively large. In this region, different temperatures with different amounts of isotopes and different climatic periods can be seen in the Holocene. These climatic changes are usually associated with cultural changes and the decline of civilizations is related to climate change. It seems that the data of this research will be used by archeology researchers such as the ancient civilizations of Iran
Dr Naser Shafieisabet, Masoudeh Nikoeifard, Dr Neginsadat Mirvahedi,
Volume 0, Issue 0 (3-1921)
Abstract
Villagers' self-organization as a collaborative process plays a fundamental role in promoting sustainable livelihoods in rural areas. This study was carried out to identify the driving forces affecting the self-organization of villagers and improving sustainable rural livelihood in Ashtian County in Iran. This qualitative research was conducted with an analytical-exploratory approach and through a semi-structured questionnaire and interviews with 30 experts. Collected qualitative data were analyzed using the Delphi method and MicMac software to identify relationships and patterns between concepts. The findings revealed that the distribution of factors and variables influencing the improvement of sustainable rural livelihoods in the studied area was unstable. Also, among the 24 primary influential factors, the 10 factors that had the highest score were identified as the fundamental drivers influencing the future process of self-organization of villagers aligned with sustainable rural livelihood. Drivers of innovation and creativity of villagers in the fields of agricultural and non-agricultural activities, skills and experience of villagers in group activities, establishing local organizations as an Individual factor; drivers of Increasing the spirit of entrepreneurship, launching and promoting new local businesses as a psychological factor; Drivers of Increasing participation, cooperation and sense of responsibility in agricultural and non-agricultural activities as a social factor; Drivers of empowering villagers and increasing their awareness and social and economic skills, Taking advantage of new IT and ICT technologies in the process of structural empowerment of them in the direction of self-organization as an education and empowerment factor; Drivers of access to various and reliable financial resources for use in agricultural and non-agricultural activities as an economic factor; Drivers of delegating authority to villagers in line with local planning and decentralization as a planning and management factor, and finally drivers of supporting the creation and development of local businesses and diversifying the agricultural and non-agricultural activities of villagers, as well as increasing investment in the process of innovative businesses as a socio-economic support factor.
, ,
Volume 1, Issue 1 (9-2002)
Abstract
, ,
Volume 13, Issue 29 (9-2013)
Abstract
, ,
Volume 13, Issue 29 (9-2013)
Abstract
, ,
Volume 14, Issue 32 (6-2014)
Abstract
Volume 15, Issue 38 (4-2015)
Abstract
, , , ,
Volume 15, Issue 38 (4-2015)
Abstract
,
Volume 15, Issue 38 (4-2015)
Abstract
Saeed Zanganeh,
Volume 15, Issue 38 (4-2015)
Abstract
Abstract
Urban form can be affected by diverse factors in different times. Socio- economic, political and physical factors are among the main contributors. So, one of the most important challenges of urban planners is measuring and identifying urban development pattern in order to direct and strengthen it to sustainable pattern and right direction. The case study of the present paper is the city of Yazd, a middle-sized city in the center of Iran, and the studied years are 1975, 1987, 2000 and 2010. To achieve the main objective of the paper, measuring Yazd growth and expansion by spatial metrics, it has used remote sensing data and satellite imageries and ArcGIS software. The conclusion revealed that in four periods of study, complexity or irregularity of the urban patch shapes has increased, centrality or average distance of the dispersed parts to the city center has decreased, compactness or the number and area of patches their distance from each other has decreased, porosity or ratio of open space has increased and finally population density of city has decreased in a large amount. Therefore, all perimeters show that the temporal - spatial form of Yazd has moved from compact to sprawl. Due to many undesired impacts of urban sprawl, urban planners and authorities are required to use adherent techniques and policies to control urban sprawl and to direct it toward more sustainable directions.
Zahra Hejazizadeh, Parisa Sadat Ashofteh, Ebrahim Fatahi, Zahra Gholampour,
Volume 15, Issue 38 (4-2015)
Abstract
Abstract
In this study, the predicted monthly temperature and rainfall data from HadCM3 model (base period, ۱۹۷۲-۲۰۰۱) and next period (۲۰۱۱-۲۰۴۰) under A2emission scenario were used to investigate the impacts of climate change on runoff variations in the Kor river basin. HadCM3 model output was downscaled based on a temporal downscaling approach (Change Factor) and spatial downscaling approach (Proportional) for the basin. The time series of monthly temperature and precipitation were produced in future period. The results showed that temperature and rainfall will increase and decrease in the future period relative to the base period, respectively. Then, the calibrated IHACRES model was used to model rainfall-runoff relationships in the Kor river basin. Then, the downscaled monthly temperature and rainfall time series in next period were employed to rainfall-runoff model and the monthly runoff time series were simulated for period ۲۰۱۱- ۲۰۴۰. The comparison of future period runoff relative to observed period showed that the annual runoff in the basin for period ۲۰۱۱-۲۰۴۰ will decrease about ۹٫۴۳% with respect to base period.
