Showing 229 results for Ca
Mahsa Asadi Aziz Abadi, Keramat Alah Ziari, Mohsen Vatan Khahi,
Volume 20, Issue 56 (3-2020)
Abstract
A city is a vibrant, dynamic, and evolving phenomenon that grows and spreads over time and space, and is exhausted and degraded.It also faces crises such as natural hazards and artifacts, resulting from human relationships and physical elements, on the one hand, and social, economic, cultural, geographical, political, and historical conditions on the other. The deteriorated urban fabric, which has physical, functional and operational deterioration, are resistant to the above-mentioned crises and has low vulnerability. Therefore, the need of intervening in these fabrics is crucial for balancing, coordinating the foundations of social life, and improving the urban structure. In this regard, in this research, priority is given to the dimension of resilient deteriorated urban fabric based on a disaster resilience of place model which is one of the models of urban resilience measurement. This research is a descriptive-analytical according to method and is developmental-applied research in terms of the purpose. Also, Expert Choice software and AHP model are used to analyze the collected data by using a questionnaire. The results of the research indicate that, in three macro areas of Karaj, Hesarak and Mehrshahr, the physical-environmental resilience dimension has the highest weight and organizational-institutional resilience has the least weight. Overall, regarding prioritization of resilience dimensions, criteria and indicators, an increasing per capita of vital use in study areas, changing the economic structure of residents, as well as increasing the skill and coherence of citizens to deal with hazards and crises are important.
Mohammad Motamedi, Mohammad Gharavi,
Volume 20, Issue 56 (3-2020)
Abstract
Cities are dramatically turning into complex social, economic, and environmental systems. Each urban system is vulnerable when it can not adapt to its changing conditions and critical situations. Therefore, in recent decades, natural disaster response approaches have introduced a new concept of urban resilience to prepare for disaster as much as possible. Is. Despite the recent attention and the abundant use of the concept of resilience in different areas of theoretical and practical limitations of this concept, this study aims to explain the causal pattern of resilience of cities. The present research is based on the descriptive-causal methodology. The statistical sample of the study was compiled by 35 experts and specialists in urban planning. Fuzzy Dumbled Fan was used to achieve the research goal. The findings of this study showed that based on the values of D-R, among the four metrics of urban resilience, the physical criterion with the value (0.943) was the most effective measure of resilience in the city. Also, based on the D + R values, the physical criterion with the value of (896/2) was identified as the most important resiliency criterion in the city.
Mr Ghorbanali Karimi Dehkordi, Phd Rahmatollah Monshizadeh, Phd Bijan Rahmani,
Volume 20, Issue 56 (3-2020)
Abstract
The rapid expansion of cities and their uneven physical growth, so-called "urban creep", have corrupted the villages and their surrounding lands, causing irregular conversion of agricultural lands and degradation of environmental resources. This situation has also been widespread in Shahrekord, the capital of Chaharmahal and Bakhtiari province. The purpose of this descriptive-survey research is to determine the physical developments of rural settlements around Shahrekord with emphasis on urban sprwal. The statistical population is household heads of rural areas (15000 people). Using the Krejcie and Morgan table, 400 individuals were selected. The tool used is a researcher-made questionnaire on three dimensions of economic, social, cultural and environmental physical consequences. Data were analyzed using one-sample t-test and Friedman test. The results show that the consequences of urban sprawl are respectively environmental-physical consequences (3/98), economic consequences (3/96) and socio-cultural consequences (3/89 (. The most important environmental-physical consequences are increased environmental pollution, destruction of traditional architecture, destruction of biodiversity; major economic consequences of stock markets and rising land and housing prices, diminishing villagers' reluctance to productive activities (agriculture and livestock), capital flight from villages And their savings in the city and the rising cost of living amidst the socio-cultural consequences of luxury and the tendency to consume luxury goods, reduce solidarity and participation, crowding and crowding in cities, modeling of life and urbanization culture. have been.
Nazli Pakro, Arash Saghafi Asl,
Volume 20, Issue 57 (6-2020)
Abstract
The purpose of this research was Historical Urban Texture Study based on the Experiences of Intervention of Birjand in accordance with the historic city of Pennsylvania. Therefore, in this study, we had uses of library study. In this research, according to the Delphi method, three stages of field survey were prepared. The first stage of open field study is considered to be all effective factors. The second stage of the field survey is weighted and the third stage with appropriate and desirable strategic scenarios for the development of the historical texture and reduction and redevelopment of the presentation. In this research, The data were analyzed using descriptive and then inferential statistics using SPSS 21, MICAC and MICAC software, as well as for mapping the city and the study area using the ARC GIS Geographic Information System (GIS). The results showed that the historical context of Birjand is in good condition in terms of citizens' access to urban uses (educational, cultural, recreational, green spaces and sports) which this matter was same adaptive with Pennsylvania. According to the results of private sector investment, people's participation in the creation of traditional mechanisms has a great influence on the preservation of historical works, and this should be taken into account in preserving historical works. Despite the problems in the neighborhood, citizens are happy with the neighborhood, which can increase satisfaction by fixing problems and organizing the textures. According to the results of the cross-correlation matrix in the MIC-Mac software, among the 28 key factors identified, 10 factors of citizens' financial ability, municipality performance, specific rules and regulations for exhausted and historic textures, literacy rates, population density, price Land, detailed design criteria, cultural convergence with adjacent tissues, have a direct and indirect effect on regeneration. The scenario of the fundamental movement to revive Birjand's historic texture in line with the historic city of Pennsylvania is the best scenario, and the revival of Birjand's historic texture is best achieved in this scenario, in line with the historic Pennsylvania city.
Dr Sayyad Asghari, Roholah Jalilyan, Dr Noshin Pirozineghad, Dr Aghil Madadi, Milad Yadeghari,
Volume 20, Issue 58 (9-2020)
Abstract
Water is one of most important human needs for life. According to importance of subject, discussion of management and utilization of water resources has become one of the most important global issues. Remote sensing data are often used in water body extraction studies and type of remote sensing data used plays an important role in water body extraction. In this study, ability of Landsat satellite with application of water indices, to extraction of Gamasiab River in Kermanshah and comparing these indices have been investigated. Specific feature of Low width and shallow rivers has increased the complexity of studies of such rivers using available data. Water body extraction from remote sensing images has been over the past two decades. Water indices were first developed using Landsat TM and Landsat ETM. But its better performance in Landsat 8 is well documented by the researchers. In this study, NDWI, MNDWI, AWEI_nsh, AWEI_sh and WRI indices were used. With extracting optimal threshold from histogram of indices and applying this threshold, the study area was classified into two classes of water and non-water. Then overall accuracy and kappa coefficient values were taken from each of the indices. Finally, AWEI index with overall accuracy of 99.09% and a Kappa coefficient of 0.98 was the best response among the indices in the study area. The results this study showed that approach can easily extract water from satellite imagery.
Mohtaram Mirzaeian, Dr Bijan Rahmani, Dr Majid Shams, Dr Abbas Malekhoseini,
Volume 20, Issue 58 (9-2020)
Abstract
The real world has been created of extremely complex mosaics. The regional analysis entails the study of the mechanism of the processes involved in systems that are capable to explain the emergence, growth and decline of a region, but like any other geographic research, doing comparison in such a study is inevitable. The cities of the world are now the homes of more than half of the world’s population. Perhaps the most important global challenge of our age is to make sure that whether the planet remains habitable and provides sufficient resources for future generations. In this study, a descriptive-analytic method has been used to analyze the effects of information and communication technology in urban sustainable development in west urban areas of Kermanshah province. The statistical population of the study consisted of 184642 people that 386 individuals were randomly selected as the sample. The required data were collected by documentary-library method and field study and analyzed and processed using SPSS software and variance analysis model. The results showed that the cities of Qasr-eShirin, Gilan-e Gharb, KerendGharb, Sarpol-e Zahab and Islam AbadGharb obtained the first to fifth ranks respectively in terms of the affectability from information and communication technology in sustainable urban development.
Dr Yagob Dinpashoh, Miss Masoumeh Foroughi,
Volume 20, Issue 58 (9-2020)
Abstract
Reference evapotranspiration (ET0) is a climatic parameter and can be computed from weather data. It is one of the most important hydrological parameters for calculating crop water demand, scheduling irrigation systems, preparing input data to hydrological water-balance models, regional water resources assessment, and planning and management for a region and/or a basin. The climatic data from synoptic stations with more than 20 years continues record in West Azarbaijan province was used. The well-known FAO-PM56 method was used to calculate the ET0. Then Multiple linear Regression (MLR) was used to estimate the ET0. The RMSE, MEA, NSH, and R2 were used to evaluate the performance of the MLR model. Then, the correlation coefficient (r) between ET0 and each of the meteorological parameters was obtained. And finally, with using Path analysis method, the influence of direct (P) and indirect effects of the meteorological parameters on ET0 was calculated. In the studied synoptic stations, NSH between 0.91 and 0.99, R2 between 0.91 and 0.99, RMSE between 0.05 and 0.15, and MEA between 0.04 and 0.12 were obtained. Also, it was found that the wind speed at all of stations had a significant correlation (at the 0.01% level) with ET0. The path analysis results showed that the maximum value of P (direct effect of meteorological parameters on ET0) in all of the stations belongs to wind speed. The P value of wind speed in Urmia equal to 0.85, Piranshahr equal to 0.99, Takab equal to 0.97, Khoy equal to 0.90, Sardasht equal to 1.06, and Mahabad equal to 0.78 are obtained.
Mohammad Motamedi,
Volume 20, Issue 58 (9-2020)
Abstract
One of the main tasks of urban and regional planners is the allocation of land to various urban uses, taking into account the role and function of the city, the city's economy, as well as the impact of interoperability of the users on each other. The topic of optimal location of therapeutic use is considered with consideration of effective parameters and factors in this research. According to the current situation in Shirvan, there are 3 clinics in Shirvan that their distribution and location seems to be inappropriate. Therefore, for prospective plans and according to the horizontal development of the city, assessment of these bases it is also a good idea to suggest places to establish clinics. This research is aimed at finding optimal location of clinics in Shirvan city by providing appropriate model. The research method is descriptive-analytical. In the first stage, identification and investigation of the effective factors on site selection of databases was investigated. Then using Arc GIS software, after completing the data gathering steps, preparing information layers, classifying and evaluating the layers, and weighing and overlapping the information layers were designed to prioritize the lands of the city of Shirvan for the establishment of clinics. The results showed that the clinics focus on the eastern side of the city, and central and western parts of the city are severely restricted in terms of access to clinics, and the population of 83,000 people in the city is only 28136 people in The standard radius of clinics is standard; in other words, about 75% of the population of the city is outside the standard radius of clinics and the radius of access to clinics is not suitable for citizens of the city. The city of Shirvan needs another hospital that is located in a location on the western side of the city.
Ahmad Asadi, Ebrahim Akbari,
Volume 20, Issue 58 (9-2020)
Abstract
The present study is descriptive-analytical and for the purpose of application. The main objective of the present research is to develop a combination of quality of life indicators for neighborhoods in District 2 of Mashhad. The required information was obtained from the municipality of Mashhad and the questionnaire was used. According to the population of Region 2 in 1395, which is 513365 people, according to the Cochran formula, 383 questionnaires were arranged. The questionnaire was completed after the preparation and implementation of experts' opinions by referring at the level of the studied sites. The required criteria were prepared and standardized in the form of spatial information in the GIS environment. Economic, social and access areas were selected as the main criteria for research and were identified for each of the following criteria. Subsequently, using spatial analysis and multi-criteria decision making model (ANP), the final quality of life index was derived from the integration of indicators. The results indicate a good quality of life in the central neighborhoods, and there are no marginal areas of desirable quality. It also increases the level of quality of life in the vicinity of the recreational centers and follows the spatial patterns. Part of the margin of the agent's neighborhoods, the martyr Basir and Hedayat, which are the marginal areas of the study area, are not in the best of all three territories; and other neighborhoods due to easy access to public services, including health services, training, and facility focus Modern welfare has a better quality of life than other neighborhoods, of which 11675700 square meters, which is equivalent to 30 percent of the area of the study area, has a very good quality of life. Also, sites that are very low in terms of economic and social indicators are moderate in terms of access. In the following, the results of spatial statistics tests (spatial spatial correlation and J statistics) indicate the distribution of the cluster model of quality of life. In other words, quality of life indicators do not have the same spatial distribution in the study area.
Saeedeh Feizi, Mostafa Basiri,
Volume 20, Issue 58 (9-2020)
Abstract
The concept of the city's landscape is connected with the objectivity and subjectivity of that city. Therefore, in order to manage this concept at night, in addition to functional-physical manifestations of the city, we should focus on the perceptual issues of citizens, which may have roots in their ancient identity, religion and customs. By accepting this hypothesis, a suitable model for night-time urban landscape management should be considered as a model that reveals both the physical and functional aesthetics of the city, as well as the perceptual and psychological components of the citizens from the night view. Nowadays, with the expansion of night life, the concepts of the quality of the location of urban landscapes at night has became as important as day. The aim of this study is to evaluate the relationship between lighting and the sense of dependency that is one of the key factors in location's quality and the role of new lighting technologies in promoting the Social-physical concept of sense of dependency and its impact on the transformation of the environment into a more humane urban environment. The research is a survey in which, for data gathering, a questionnaire with different images of the study area has been distributed among the selected statistical population. The findings indicate that the vitality and subjective image's of citizens are directly related, and the amount of lighting and its color and the way of lighting have a positive effect on urban nightlife.
Mr Moslem Nori, Di Rostam Saberifar, Professor Esmaeil Aliakbari,
Volume 20, Issue 58 (9-2020)
Abstract
The change in the way cities operate and benefit from ICTs, etc., has led to population dispersal, activity, and housing. This trend, along with the devastating social and environmental impacts, has had quite visible and measurable economic consequences. A comparative study would be very helpful to avoid the implications of measuring the occurrence of this process and the impact of national and local factors on it. Therefore, the purpose of the present study is to compare the dispersal trend of the two cities of Esfarain and Bojnourd. In this regard, the present study is applied in terms of purpose and analytical-comparative in terms of research method. Required data were collected from documentary library studies and Heldern, Shannon entropy and Gini coefficients were used to analyze the data. The results showed that according to Helderen's model, 84% of physical growth in Esfarain between 1345 and 1345 was related to population growth and about 16% to horizontal and spherical growth. For Bojnourd, this was also about 88% of the population growth and about 12% of the horizontal and spiral growth, which is slightly different from that of Esfarain. The Shannon entropy model also shows the sparse growth of physical expansion in the two cities of Esfarain and Bojnourd. The Gini coefficient calculated for Esfarain city is 0.096 and for Bojnourd city is 0.054 which indicates that population growth (Espalier) of Esfarain city is 0.015% more than Bojnourd city. Since the continuation of such conditions has numerous environmental, social and economic consequences for the residents of the cities concerned, it is advisable to strategically research, control and manage the physical development of the city and utilize the interpersonal development policy.
Parviz Kardavani, Farideh Asadian, Mr Mohammad Reza Fallah,
Volume 20, Issue 59 (12-2020)
Abstract
The irregular exploitation of groundwater aquifers in Shahriyar Plain has caused the drop of ground-water level in the region. Artificial nourishment of aquifers can increase the size of ground-water storage, reduce its level drop, and also prevent the advance of brine and drying of the aqueducts. In this study, we tried to integrate GIS and Boolean logic in order to identify the best areas for artificial recharge in Shahriar Plain. So, the seven factors (slope, permeability, thickness of alluvium, portability, both drop zones, land use and electrical conductivity) of water samples were specified in GIS and then respective maps were prepared. Then, using the acquired weight of each layer, maps for each weighted factors of locating were integrated. Using Boolean logic, final maps were prepared in two classes: suitable and unsuitable. Finally, the best place for the implementation of artificial recharge of aquifers in the region was identified. Results indicated that the suitable regions mostly lie in areas with slopes less than 3 % and that they are mostly near Chitgar river.
Taher Valipour, Mohammad Mehdi Hosseinzadeh, , Saeedeh M.biranvand,
Volume 20, Issue 59 (12-2020)
Abstract
Channel retreat are an important process in the river's morphodynamics, which affects channel variation, flood plain development and habitat development. Structures and farmland the border of the Lavij River Faces the risks of river bed change every year. Therefore, there is a need for a reliable method to determine the river bank retreat and predict the river bank Stability. In this study, with the aim of investigation of the risk of erosion and identification of areas susceptible to erosion in the Lavij River, Using BEHI and NBS models, the risk of side erosion was determined in 7 sections of this river. The results of the NBS model using the tnb / tbkf index showed that the rate of erosion of the Lavij river bank in all studied cross sections, except for cross sections 2 and 6 ,erosion rate is high and very hight. According to the indicator (dnb / dbkf), the bank erosion rate of the Lavij River, except for sections 4 and 5, is approximately consistent with the erosion trend obtained from the first index (tnb / tbkf). According the BEHI model, cross sections 5, 4, 3, 1 and 6 show a high incidence of instability and have a great potential for bank erosion and sediment production. Also, cross section 2 shows the medium instability status. Cross Section 7 and 2 show a high degree of instability, which has a high potential for bank erosion and sediment production. Finally, Kruskal-Wallis statistical test was fitted to evaluate the results matching and the results showed that all three indicators were almost identical to each other in the assessment of bank erosion.
Mojtaba Shahnazari, Zahra Hejazizadeh, Mohammad Saligheh,
Volume 20, Issue 59 (12-2020)
Abstract
Abstract
In this research, while studying climate conditions in the current period and analyzing changes in temperature, precipitation level, and the sunlight received, current conditions were also analyzed based on daily data from synoptic stations in the region, which had meteorological data recorded for at least 30 years. Given the environmental conditions necessary for the growth of rice, the availability of its phenological data, its high-low temperature thresholds, the Degree Day systems needed for the completion of its life cycle, and the phenological processes related to its economic production, a suitable agricultural calendar was specified. During the March-July period, this calendar showed variations in different provinces. Based on the current temperature conditions and the probable continued warming trend of the planet in the decades to come, nwoDscale was applied to the output from the atmospheric general circulation model MCdaH3 under scenario using LARS-WG5 model. In this study, years between 1969 and 1990 were used as the base period, while years between 2046 and 2065 were studied as the future period. Temperature and precipitation conditions for the future period were simulated. Obtained output was then studied and compared with temperature conditions that were suitable for the plant to grow in the region. With some differences, results showed that the agricultural calendar for rice in Gilan and Mazandaran provinces will shift to winter. Given the different temperature conditions of Golestan province, its agricultural calendar will shift to spring.
Shamsi Sadat Mir Asadollahi, Sadraldin Motavali, Gholam Reza Janbaz Ghobadi,
Volume 20, Issue 59 (12-2020)
Abstract
Natural disasters are a set of harmful events that are natural origin that sometimes human factors are also effective in exacerbating. In the same vein strengthening the social and economic component and after that resiliency can play an important and effective role in reducing flood damage. This research is applied in terms of purpose and descriptive –analytical and field nature. Survey method and data gathering tool were closed questionnaires, the analysis method is based on correlation and regression test. The statistical population includes citizens living around the river and flood areas that 383 people selected as sample and the questionnaire was distributed by cluster sampling among respondents, according to research finding , the average social resilience 1/60 , average economic aberration ( the amount of damage ) 4/53 ,average capacity with ability to compensate 8/69 , eventually average return to appropriate condition 4/67 .in the test section, hypotheses are determined according to the result of the regression test and correlation which has a significant relationship between urban and urban spatial and social dimensions. Strengthen local organs and organizations in a decentralized state , one of the important ways to increase the social participation of citizens of Gorgan during the crisis.by providing people's participation and strengthening the people's economic ability when natural hazards occur including flood, the initiative of the people is strengthened and the scope for reducing the damage caused by the flood is reduced . people are faced with real and tangible issues with the executive and so on their gap crisis management and conflicts of interest will diminish.
Elmira Azimi, Dariush Sattarzadeh, Lida Bolillan, Akbar Abdollahzadeh Tarf, Mahsa Faramarzi Asli,
Volume 20, Issue 59 (12-2020)
Abstract
The prevalence of chronic health problems is increasing, both in terms of physical health and mental health in modern societies. Meanwhile, the health of individuals in society as human capital is important in advancing the goals of thematic communities. The aim of this study was to investigate the role of physical-environmental factors on the mental health of citizens. This research is applied in terms of purpose and descriptive-analytical method. The statistical population of citizens living in Ardabil was estimated to be 384 using the Cochranchr('39')s formula. The field data collection tool was a researcher-made questionnaire whose validity was confirmed by formal validity and reliability using Cronbachchr('39')s alpha test and combined reliability. The results of this study showed that legibility and visual quality, access to urban green space, security of urban space, quality of urban furniture, mixing and variety of uses have a positive and significant effect on the mental health of citizens. Considering the value of the path coefficient obtained for the independent research variables, among the identified variables, the quality of urban green space with the path coefficient value of 0.44 had the highest path coefficient and had the greatest effect on the dependent variable, ie mental health of citizens. Also, the mixing variable and the variety of uses with a path coefficient value of 0.21 had the least effect on mental health.
Mohammad Golmohammadi, Mohammad Adalatkhah, Akbar Abdollahzadeh Tarf,
Volume 20, Issue 59 (12-2020)
Abstract
Many factors, including cultural factors, currents and schools of thought, and patterns of urbanization in the world are influential in the physical structure of a city. The physical structure of the city is the result of all the forces that give rise to the formation and formation of a settlement and has an objective and mental appearance. The growth and development of cities, due to various events in all historical periods, has been declining and rising. Nowadays, knowledge of the physical structure of the city and the reasons that govern its spatial expansion in different periods is necessary to control its expansion and is one of the important factors influencing the success of urban planners and designers. This study was written with the aim of identifying and prioritizing cultural factors affecting the physical structure of the city with emphasis on indigenous architecture. The present research is applied in terms of purpose and descriptive-analytical in terms of method. Library and field methods were used to collect information. The statistical population of the study consisted of experts and specialists in architecture and urban planning, with a sample size of 30 people. In order to achieve the objectives of this study, the fuzzy Delphi technique and the BMW model were used. The results of fuzzy Delphi technique confirmed the identified factors and sub-factors. The results of the BMW model showed that among the identified factors, the privacy factor with a final score of 0.298 in the first place, the security quality factor with a final score of 0.273 in the second place, the nature connection factor and social interactions with a final score of 220 / 0 is in the third place and the hierarchical factor is in the fourth place with a final score of 0.209.
Nayereh Akhavan, Narjessadat Hossainy Nasrabady,
Volume 20, Issue 59 (12-2020)
Abstract
Gender distribution in the centers of power and the level of participation in elections from a gender perspective are among the ambiguous issues that show the composition and quality of power structures in political-spatial units. From a geopolitical perspective, how power is distributed through representation and political participation through elections reflects the presence or absence of gender justice in power structures. Given the high geopolitical weight of women in the Iranian population pyramid, the present study has reviewed the city and village council elections in Fars province from a geopolitical perspective of gender. For this purpose, by using descriptive and survey methods and by examining different statistics and data in the three rounds of city and village council elections in Fars province, the gender distribution of the elected representatives in these three rounds has been investigated. Is. The results showed that in the first round of urban and rural elections in Fars province, men held 90% of the seats. In the second round, this ratio reaches 80%, and in fact, there is a relative improvement in the gender distribution of representatives. In the third round, however, the sinusoidal trend reverses to the first round so that the gender weight of the representation remains established in the masculine structure.
Dr Parviz Zeaiean Firoozabadi,
Volume 20, Issue 59 (12-2020)
Abstract
Various satellite remote sensing data, images and products have proven their place in drought, drought and agriculture studies since the production of this type of information resource. Visible, near-infrared and thermal bands are among the most widely used in the production of products such as vegetation and surface temperature. In this study, from MODIS sensor data to investigate and find the coefficients of spatial relationship between vegetation-surface temperature index (NDVI-TS) and NDVI-ΔTS to extract the time of agricultural drought from June to October 2007 to 2010 in the catchment Siminehrood has been extracted from the Temperature-Vegetation Condition Index (VTCI) and the Water Lack Index (WDI), which are able to detect drought stress on a regional scale. The results of this study showed that in both indicators, the drought stress situation was higher in 2007 and 2008. Also based on the NDVI-TS space relationship in all the years 2007 to 2010 the high slope of the triangular space for the hot edge is negative. This means that with increasing NDVI, the LST level decreases while for the cold edge the slope is positive. In addition, the slope obtained from the NDVI-ΔTS space relationship is negative for the dry line, ie the dry line or the minimum transpiration-sweat line (ETR) shows a negative correlation with NDVI. While for the wet line, especially in 2010, the slope is positive and in other years, no significant change is seen. The present study showed that the VTCI threshold for drought stress was severe in 2007 and 2008.
Parisa Ahadi, Shahriar Khaledi, Mahmoud Ahmadi,
Volume 21, Issue 60 (3-2021)
Abstract
Dust is referred to sediments of less than 100 microns in size which are transmitted as suspended particles. Dust storms are events which naturally occur in arid and semi-arid areas, especially in subtropical latitudes. One of the most known sources of dust is the west of Asia, including Arabian Peninsula, Syria, Iraq, and Iran, especially Khuzestan Province. The purpose of this study is to investigate the frequency and trend of dust phenomena on hourly, monthly, seasonal and annual scale between 1995 and 2015 in Khuzestan Province. The method in this study is based on statistical computation of dust parameters and also the trend analysis of data based on Mann-Kendall test and spatial distribution maps of dust phenomena. The results suggests that 78.57 percent of dust event are occurred between 9.30 am to 15.30 pm local time, concurrent with peak of sun radiation and earth surface warming, dryness of soil and local pressure difference. The hourly trend analysis is increasing and significant in all hours and the highest increase occurred at 9.30 pm to 12.30 pm.49 percent of dusty days occurred in June, July and May and also 73 percent of them are in spring and summer as following from temperature increase and water and soil resources drying in the province. The seasonal and annual spatial distribution of dust indicates that most of dusty days in all seasons are located in west of province which suggests dominance of external sources as the main source of dust and the importance of topography factor in this area.The Z value spatial analysis suggests high increase of dust event in recent 20 years in southeast, south and central areas of the province and also on last hours of day which demonstrator development of internal sources activities in increasing trend of dust event in recent decades.
