- journal of Geography and Environmental Hazards is a bilingual scientific-research journal in Persian and English. Thi... morejournal of Geography and Environmental Hazards is a bilingual scientific-research journal in Persian and English. This journal has been publishing the authors' articles since 2012 by Ferdowsi University of Mashhad and the participation of Isfahan, Tabriz, Shahid Beheshti, Zahedan and Hormizgan Universities. Geography and Environmental Hazards has been launched due to the increasing trend of environmental hazards caused by global warming, population growth and industrial development, as well as the high degree of geographical risk in Iran. Journal of Geography and Environmental Hazards is the first scientific-research journal in Iran that highlights the important issue of environmental hazards and tries to get the results of research on geographical distribution, geographical causes, management and planning to reduce the effects of natural hazards and prevent occurrence. Persian authors who have articles in their own language must submit a comprehensive abstract in English. Authors must send the electronic version of the article in both word and pdf formats to one of the following addresses:edit
In recent years, most risk-related research has shifted its paradigm from a loss-reduction model to a more inclusive local community model. Accordingly, the views and theories of disaster management and sustainable development seek to... more
In recent years, most risk-related research has shifted its paradigm from a loss-reduction model to a more inclusive local community model. Accordingly, the views and theories of disaster management and sustainable development seek to create resilient societies against natural hazards. Resilience is the degree of resistance of systems, their ability to tolerate change and disruption and the continuity of relationships between individuals and variables. This study, considering such a definition for resilience, evaluates the resilience of seven neighborhoods of Sari city (intersection of section eight - Salman Fars - Piroozi, Tabarestan, central city center - municipality near Babol Gate, Moallem, Besat Free Zone - Nehzat and Shahband and Barrier) has dealt with natural hazards. The basis of spatial analysis in this research is the divisions of neighborhood planning units (according to the comprehensive plan of the city). The sample population is equal to the statistical population (18 experts in municipal, housing and urban planning, natural resources, etc.). Seven indicators (building strength, land and urban infrastructure, open spaces, physical environment, uses, economic and social) were designed and the required data were obtained; finally, various indicators were weighted by experts to make environmental risk planning desirable. Evaluation of urban resilience and ranking of neighborhoods in Sari city has been done using WP and WASPAS evaluation models. The results show that out of seven neighborhoods in Sari, only one neighborhood (Chahar Rahbakhsh Hasht, Salman Farsi) is in very good condition and Tabarestan neighborhood is in good condition in terms of resilience. Also, according to the results of both models, the northern regions are in a very good and good condition in terms of resilience, while the southern and central regions are in a very weak and alert state.
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Over the past decade, municipal waste production has increased dramatically due to increasing global population and the rate urbanization. Therefore, one of the important issues that has been used in recent years and has been discussed to... more
Over the past decade, municipal waste production has increased dramatically due to increasing global population and the rate urbanization. Therefore, one of the important issues that has been used in recent years and has been discussed to increase the efficiency and productivity of transportation systems is the discussion of routing of waste transportation machines. In addition, poor management and inappropriate collection and storage since it creates environmental problems in the urban ecosystem is considered a global challenge, as the presentation of these urban services has been significantly neglected due to lack of sufficient data and information. The aim of this study was to provide an appropriate solution for proper collection of waste in 40 neighborhoods of Zabul city to minimize the time of mission and increase the satisfaction of citizens of such urban services. The research method is descriptive and applied studies based on attribution algenomy and field studies. In order to conduct this study, metaheuristic algorithm of colonial competition and Arc GIS software was used and all the related programming was done in MATLAB software environment. The results indicated that colonial competitive algorithm with 20 replications at 15 replications with a time equal to 4.11 seconds with 71% confidence coefficient was obtained in the best possible state and showed the order of the best intersections. Confidence coefficient was obtained in the best possible state and showed the order of the best intersections. Confidence coefficient was obtained in the best possible state and showed the order of the best intersections.
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Saffron as the most valuable agricultural and medicinal product in the world is one of the plants that due to its adaptation to drought, has a significant role in the economic and social situation of arid and semi-arid regions, including... more
Saffron as the most valuable agricultural and medicinal product in the world is one of the plants that due to its adaptation to drought, has a significant role in the economic and social situation of arid and semi-arid regions, including Rashtkhar village. Accordingly, given that natural disasters have threatened the lives of humans, especially villagers, economically and socially, and sometimes disrupted their lives. Therefore, the purpose of this study is to analyze the factors affecting the psychological competence of rural saffron farmers according to production risk management strategies in Rashtkhar rural area. This research has been done by descriptive-analytical method. In this regard, the factors affecting psychological ability in 355 saffron working families living in 13 villages with more than 100 households in this district were studied. The field data collection tool in this study was a researcher-made questionnaire whose apparent and content validity was obtained by obtaining the opinions of specialists, experts and professors and after several stages of correction and revision. Its reliability was confirmed using a preliminary test through 30 questionnaires, which is equal to 0.86. For data analysis, the stakeholder matrix in the integrated model of ASM, SPSS software and for spatial analysis, software and Topsis-Fazi were used. Findings indicate that there is a significant relationship between the factors affecting the psychological empowerment of rural saffron farmers and risk-based production management. Also, the research findings show that among the factors affecting psychological empowerment, the factor of ability and decision-making in production risk-based management strategies by saffron farmers is more important. Therefore, the results show that it is better to hold training classes for empowerment in order to better use risk management among saffron farmers, not far from the minds of government officials and agents.
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The present study is a field research with a descriptive-analytical approach and seeks to answer the basic question: What are the key components of increasing physical resilience in the 10th district of Tehran in the future according to... more
The present study is a field research with a descriptive-analytical approach and seeks to answer the basic question: What are the key components of increasing physical resilience in the 10th district of Tehran in the future according to the current situation? In this research, in order to codify a theoretical framework at first, the subject is described in detail using the documentary method, literature and theoretical foundations, and then by relying on the environmental scanning technique and the Delphi method, the experimental data is extracted. The statistical population includes 20 urban experts and specialists. Also, the sampling method used is a purposive sampling. In the first step of the research, based on the review of theoretical texts and documents about resilience and dysfunctional urban texture with emphasis on the physical dimension, 41 variables were extracted and then in the next step, experts' opinions regarding the outcomes of these variables on each other through distribution of 20 Questionnaires were collected and finally the answers were analyzed using structural interaction analysis method in MICMAC software. In this analysis, the extent of direct and indirect effects of variables on each other and on the future trend of physical resilience in the district 10 of Tehran against earthquake was determined and then the key explanatory factors of the research topic were extracted. In the other words, out of a total of 41 influential initial variables, 11 variables were chosen as the key factors affecting the future trend of physical resilience in the district 10 of Tehran in the face of earthquakes. The aftermath of this study represents that the relationships of key components are so effectual and impressionable.
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Urbanization is one of the consequences of the industrial revolution, which changed the development process and led to the expansion of migration to the city. One of the main results of the expansion of urbanization in recent decades is... more
Urbanization is one of the consequences of the industrial revolution, which changed the development process and led to the expansion of migration to the city. One of the main results of the expansion of urbanization in recent decades is land use change in cities and their uneven growth, which has made managing urban growth one of the most important challenges of the 21st century. The present study evaluated the changes in the lands of Torbat-e Jam city during the years 2000 to 2019 and then predicts these changes until 1420 AH. The research method is descriptive-analytical. Landsat images, sensors, ETMs of 2000 and 2010 and OLI sensors of 2019 have been used to collect data in this study. After classifying the images, in order to find out the changes in the land use of Torbat-e Jam city and to predict the changes until 1420, the Markov and CA chain model has been used. The results obtained in the period of 2000, 2010 and 2019 show that the area of all land uses in the study area except barren land use has been increasing. Also, the forecast of the four floors of land cover, including urban lands, agriculture, barren and green space and gardens in the city of Tor bat-e Jam on the horizon of 1404, shows that the land use of the city will increase at the horizon of 1420, so that this land use will change by 192.13%. Agricultural land use will have a decreasing trend with 71.05% and green space and gardens with 53.32% and barren land use area will have an increasing trend change with 100.87%. Finally, with the Vision Development Index, the type of urban growth was determined. Also, according to this index, the growth type of Tor bat-e Jam city is of the edge type.
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Climatic hazard is an applied science that studies, recognizes and analyzes atmospheric phenomena under internal and external controlling factors in the long run and its thematic range is very wide. Therefore, in this field,... more
Climatic hazard is an applied science that studies, recognizes and analyzes atmospheric phenomena under internal and external controlling factors in the long run and its thematic range is very wide. Therefore, in this field, methodological issues are among the scientific and intellectual tools from which no serious scholar in this field can exempt herself. Therefore, in this paper, using two types of methodologies based on positivism (statistical analysis- schematic) and meta- positivism (hermeneutic analysis and interpretation) method, subtropical high pressure changes in the warm period of the year and its effect on drought, in order to apply the results of this study Was used. The results showed that applied topics in climatological knowledge, including climate hazards, relying on a positivism methodology independently and using only statistical analysis and output of specialized software, are not able to systematic ideas in the field of management and environmental sustainability. Therefore, in this study, an attempt has been made to establish an organized trend in climatological studies in the direction of the meta-positivism method and better results by examining case samples from synoptic maps and diagrams extracted from various hermeneutic analyzes of Tropical pressure changes is obtained. Because the art of a climate expert is to convert passive texts into active texts for practical use of the results of climatic phenomena in other trends of geographical sciences such as geomorphological studies, urban geography, rural geography, political geography, etc. This, in turn, emphasizes the revival of the nature and core function of geography
Excavation in the river beds, rinsing sand and its transporting had the potential to cause physical destruction and spread in the surrounding aquatic and arid environments and mining of sand has caused environmental problems, including... more
Excavation in the river beds, rinsing sand and its transporting had the potential to cause physical destruction and spread in the surrounding aquatic and arid environments and mining of sand has caused environmental problems, including spreading dust. Tehran province is located on the southern slopes of Alborz. Also its alluvial sediments has extended from Alborz mountains to southern of Tehran province and create a suitable place for sand mines. Shahryar down town, like other parts of Iran, has many mines including silica, salt, sand and soil. Natural status and history of existence surface flows of north lands of the region, cause the accumulation of all kinds of sand mixtures in the form of alluvial sediments. In the northern part of the Shahriar alluvial lands are created by the Karaj river flood flows and now several companies are involved in sand exploitation of this region due to creating of Karaj Dam and the water cutting off from the mentioned lands. Shahryar down town like other parts of Iran has many mines including silica, salt, sand and soil. Currently, the number of sand mines is approximately 5 units. In general, the dust that penetrates into Tehran province is from the northwest direction in the direction of the Shahriar wind. This research has investigated the impact of Shahriar mines on dust intensification in Tehran province. Dust dispersion in Iran except foreign focuses have also internal origin, including dry lagoons, wasteland, sand mines and construction debris that is discharged around towns and villages without supervision. The results of the Shahriar wind showed that the dominant and semi dominant of the Shahriar wind is northwest in all seasons.
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The study area is located in the Sefidroud coastal plain in Guilan province. The required theoretical foundations and basic information have been collected based on library studies and reviews of similar researches. Landsat 5, 7, 8... more
The study area is located in the Sefidroud coastal plain in Guilan province. The required theoretical foundations and basic information have been collected based on library studies and reviews of similar researches. Landsat 5, 7, 8 satellite images with similar imaging seasons from 1987, 2002, and 2018 are the basis for remote sensing studies. The trend of land-use change in 2018 was predicted in the Idrisi TerrSet software based on the maps of 1987 and 2002, using the CA-Markov model. To determine the classification and modeling accuracy, 120 ground control random points were determined and validated by field measurement spatial reality in the study area. The river change forecast map has been obtained with fitting the model output of 2030 and the land use map of 2018. This fitting, the Sefidroud canal was divided into 4 sections in the study area, and predicted changes were examined. The integrated CA-Markov model has a good capability in terms of accuracy in predicting land use and morphology of Sefidroud. The probable changes are in the river, coastal lands, and man-made facilities and plains units in the study area. The process of these changes will be such that will undergo erosion, change in the meandering, and flooding of areas around the river. The river canal cross-sections has exhibited a decreasing trend of canal width until 2018. This is due to the reduction of Sefidroud discharge and the Caspian Sea level fall, increasing the channel width trend will occur according to the results of the CA-Markov model, until 2030. This indicates the possibility of increasing the average annual discharge of Sefidroud to about 100 (m3/s) and rising the Caspian Sea level above -27 (m) until 2030.
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Landslides are one of the most important slope movements. One of the landslide-prone areas is the area around the dams and their lake, which may cause damage to the dams. The purpose of this study was to identify areas prone to landslides... more
Landslides are one of the most important slope movements. One of the landslide-prone areas is the area around the dams and their lake, which may cause damage to the dams. The purpose of this study was to identify areas prone to landslides in the area of Shahid Abbaspour Dam, Northern Khuzestan, Iran. This research was conducted using two methods of Hayeri-Samiei and Analytical hierarchical Process. Based on this, seven factors including lithological, slope angle, fault length, road and river length, rainfall factor, rainfall intensity and earthquake were prepared. In the Hayeri-Samiei model, these seven factors are investigated and the obtained weight of each of them is placed in the general equation and in the GIS environment is converted into a zonation map and potential areas in the range are identified. In the Analytical hierarchical Process method, based on pairwise comparisons between the seven factors mentioned, considering the opinion of experts, the weight of each factor is obtained and in Expert Choice software, pairwise comparison is performed and the final weight is obtained. After studies in two methods, the most landslide-sensitive areas are in Quaternary young alluvium and lithological factor is the most important factor in the study area. In general, high-risk areas are in the southwestern part of the dam and a small part in the north. In AHP model, like Hayeri-Samiei model, the lithological factor has the greatest effect on landslides in the region. Gachsaran Formation also has very low resistance to landslides after Quaternary alluviums. In terms of slope angle, areas located at slope angles of 36-45 are prone to landslide.
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In this study, quantitative assessment of soil erosion and sediment was done using the famous RUSLE model in the framework of GIS and remote sensing technology. The results showed the erosion values of the basin vary from 0.001 to 257... more
In this study, quantitative assessment of soil erosion and sediment was done using the famous RUSLE model in the framework of GIS and remote sensing technology. The results showed the erosion values of the basin vary from 0.001 to 257 (t ha-1y-1) at the pixel level and the average erosion in the study basin is 17.62 (t ha-1y-1). Medium rangelands have high average erosion values for two reasons; One is due to the steep slope and consequently the runoff speed in the destruction and transport of particles, which intensifies the role of LS factor and weakens the vegetation factor and the other is the high values of precipitation, which shows the role of rain erosion factor (R). Classification of erosion values showed that about 42% of the study basin with value higher than 16 (t ha-1y-1) is in a severe situation in terms of soil loss. Therefore, due to the erosion situation in the study basin, the role of watershed management, soil protection, and watershed management operations with a focus on the upstream basin and in areas with high slopes is more necessary.
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Landslides are one of the natural hazards that are always associated with financial and human losses. Understanding the causes and its different types is very important for us. Identifying and determining sensitive and landslide prone... more
Landslides are one of the natural hazards that are always associated with financial and human losses. Understanding the causes and its different types is very important for us. Identifying and determining sensitive and landslide prone areas can prevent damage and provide a basis for the implementation of slope stabilization projects. In the present study, landslide risk assessment in the watershed of Galal Dam in Ilam province has been performed using Vickor multi-criteria decision making method. Accordingly, among various factors, 8 geological parameters, altitude, slope, precipitation, distance from the fault, distance from the waterway, distance from the road and land use as the most important effective parameters in the occurrence of landslides in the region, have been identified. Then, the significance coefficient of each of the effective factors in the occurrence of landslide was obtained by the method of hierarchical analysis of systems in which the geological criteria slope and precipitation gained the highest coefficient of importance. Then, based on Vickor optimization algorithm, the degree of usefulness and regret of selecting the best options (sub-basins) is determined, and finally by calculating the amount of Vickor optimal index (Q), sub-basins according to the degree of landslide sensitivity in three quality classes of sensitivity Low, medium and high susceptibility were classified. The results showed that the sub-basins of Ban Sohan, Palkaneh and Haji Bakhtiar have the highest susceptibility and the sub-basins of Chegan, Dard Mirnaser and Chegah have the lowest susceptibility to landslides. From the adaptation of zoning maps and landslides in the region, the accuracy of the map can be understood and it was also found that the Vickor model used in this study is a very suitable method for zoning the risk of landslides in the study basin.
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The purpose of this paper is to explain the factors affecting social resilience against biological hazards with emphasis on Covid-19 in order to unveil the shadowing of this phenomenon, a phenomenon that has long been discussed from its... more
The purpose of this paper is to explain the factors affecting social resilience against biological hazards with emphasis on Covid-19 in order to unveil the shadowing of this phenomenon, a phenomenon that has long been discussed from its text layers and sub-layers to different angles of attitude drills. The research method in this study, in terms of descriptive - analytical and practical purpose. To collect the required data, the library method (Covid 19 disease distribution map, valid books and articles in line with the research topic) and the survey method were used as a questionnaire and Delphi method. To analyze the data and prepare the data, SPSS software was used for the statistical population of 133156 households in Zanjan with a sample size of 321 and data analysis was performed using research analytical tools (from exploratory and confirmatory factor analysis model in the form of structural equation modeling). The results show that the analysis of conceptual characteristics using heuristic factor analysis reveals the four main explanatory factors as factors; Awareness and health with a coefficient of 0.74, attitude with a coefficient of 0.78, skill with a coefficient of 0.82, social capital and justice with a coefficient of 0.73 identified the contract and analysis of the communication structure of the identified effective factors using confirmatory factor analysis showed that the identified factors have a structural relationship It is significant for being effective in social resilience against Corona in Zanjan.
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In the decades, with the advent of technology and integrated management municipal solid waste, the methods such as recycling, biological treatment, heat treatment and sanitation have been used. The sanitary landfill method is considered... more
In the decades, with the advent of technology and integrated management municipal solid waste, the methods such as recycling, biological treatment, heat treatment and sanitation have been used. The sanitary landfill method is considered as one of the strategies in the integrated waste management hierarchy and is more common and less costly than other disposal methods. The purpose of this research to identify the environmental problems and environmental risks the place of landfill residue of Tonekabon city is the RASCAL method. This approach is used to assess the risk of landfills that are not so large and it has been used to determine the risk of groundwater contamination and gas accumulation and factors that have a greater impact on the pollution of the two factors. According to RASCAL and AHP, the leachate collection system criterion, has the greatest impact on the risk of groundwater contamination. In the context of the risk of gas accumulation, the criterion of the type of waste and the type of gas produced has the highest weight and therefore has the greatest impact on the increased risk of gas accumulation. The calculated risk for groundwater pollution is modest and the risk of accumulation of gas at the landfill site is low. Since the depth of the groundwater table in this place is more than 22 meters, and its distance from the consumer is more than two kilometers, but because of the source near the landfill, the risk of groundwater pollution in this area is high.
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With the continuous development of urbanization, and the increase of uncertainty and risk, resilience has become an important criterion for urban safety. Urban systems, as dynamic and open space systems, present certain complex... more
With the continuous development of urbanization, and the increase of uncertainty and risk, resilience has become an important criterion for urban safety. Urban systems, as dynamic and open space systems, present certain complex manifestations. Therefore, understanding urban resilience from the perspective of complex systems theory is important to achieve a full understanding of the composition and mechanism of operation of urban systems and then improve the scientific nature of urban system cognition and research. Urban areas have the largest population of the country and in addition to the nodes of consumption of resources and centers of innovation, theoretically and practically become the main area of resilience testing against natural hazards, especially earthquakes. The aim of this study was to measure the resilience of Tabriz as the largest population center in northwestern Iran and at the same time one of the most seismic cities in the country against earthquake risk. This research is descriptive-analytical in terms of method and practical in terms of purpose. Based on this, Tabriz urban resilience has been evaluated based on 14 criteria in the form of 4 main components (social, economic, institutional, physical resilience) by Delphi method and by 50 experts. For data analysis, one-sample t-test, Friedman, Kendall and path analysis in the form of SPSS software were used. Findings showed that the resilience status of Tabriz city against the occurrence of a possible earthquake of social dimension, 2.19; in the economic dimension, 2.37; in the institutional dimension, 1.94; and in the physical dimension it is 2.57. In general, the resilience of Tabriz city against earthquakes, with an average of 2.33 is undesirable. Among the four components, the physical component with the sum of direct and indirect effects explains the alpha of 0.560 and is the most effective component in the resilience of Tabriz. The four dimensions of resilience, in total, could explain 0.345 of resilience in Tabriz.
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Resilience is an integrated approach to enhance existing capacities and reduce the vulnerability of human societies to a variety of environmental crises and hazards. In this regard, one of the most important crises and hazards that have... more
Resilience is an integrated approach to enhance existing capacities and reduce the vulnerability of human societies to a variety of environmental crises and hazards. In this regard, one of the most important crises and hazards that have overshadowed all over the world in recent years is the spread of the corona virus. Considering the negative effects and harms of coronavirus outbreak in different dimensions of human societies, the aim of the present study is the future study of Tabriz resilience against coronavirus pandemic. The research method in this study is a combination of quantitative-qualitative approaches with the nature of futures study, which in order to collect information is used from the Delphi technique of elites and city managers (30 experts in the field of crisis and risk management) and to analyze information is used from the technique of cross-impact analysis in software MICMAC. Findings indicate that the most influential among the studied drivers on other drivers in terms of urban resilience against the corona pandemic are related to economic drivers such as finding a new job if the current job is lost, the vulnerability of sources of income and the existence of institutions, finance supports the most vulnerable and most influential groups related to social impulses such as collective participation in dealing with the crisis and responding appropriately and behaving in critical situations. The results also show that due to the current situation and the lack of key and strategic drivers for effective system resilience, weak in economic and social structures, the city's management system and Iran's precarious position in the international arena, the future of Tabriz resilience based on environmental hazards (corona pandemic) will be unstable.
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Heavy rain resulting from atmospheric patterns, depending on the extent of activity and the time period of its occurrence, has adverse events and consequences such as floods. The present study was conducted in order to synoptic analysis... more
Heavy rain resulting from atmospheric patterns, depending on the extent of activity and the time period of its occurrence, has adverse events and consequences such as floods. The present study was conducted in order to synoptic analysis of 171.5 mm heavy rainfall (March 19, 2017) leading to flood in Minoodasht city. The view of this study is a circular to environmental and first, the amount of rainfall at Minoodasht station was determined and by receiving upper atmosphere data from the website of the National Center for Environmental Prediction (NCEP / NCAR) and analyzing them, the causes of heavy rainfall was revealed. In order to study the synoptic conditions, using the Gardes software, sea level pressure maps were drawn, and in the upper atmosphere, geopotential height, wind vector, vorticity, omega, thickness, eddy and humidity (500 hPa level) were studied. The results of map analysis showed that during heavy rains, high pressure systems were formed in Mongolia and southern China and were caused a pressure gradient & strong front with prevailing low pressure system in Minoodasht. In the upper atmosphere, the presence of cut-off low-pressure blocking has been placed as a barrier to the west winds and has caused the flow of west winds to the study area. In addition, the high thickness of the atmosphere in the study area and the dominance of the amount of negative eddy, led to air instability and the presence of positive virtuosity cores and negative omega, indicates an unstable atmosphere on the days in the study area. Also, the inflow of moisture from moisture sources such as the Caspian Sea, the Aral Sea, the Black Sea and the Mediterranean Sea has provided special conditions for severe rainfall.
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The environment is currently experiencing different changes that are caused by both nature-induced and anthropogenic processes. Land use changes in Gharesoo Watershed noted that there is a necessary need to study ecological quality in... more
The environment is currently experiencing different changes that are caused by both nature-induced and anthropogenic processes. Land use changes in Gharesoo Watershed noted that there is a necessary need to study ecological quality in this region. In this paper, a remote sensing-based ecological index (RSEI) based on the pressure-state-response (PSR) framework, using the average data of summer images of Landsat satellite in 1989 and 2018 (ETM +/OLI/TIRS sensors), was used to evaluate the changes in ecological quality in Gharasoo watershed of Golestan province. Google Earth Engine (GEE) is used for acquiring and preparing indices, including an indicator of environmental pressure (NDBI), an indicator of environmental state (NDVI) and indicators of local climate changes in response to environmental changes and concerns (LST and LSM). After preparing the indices, the weight of each index was extracted using the principal component analysis (PCA), and then the ecological quality index was created based on the first component of PCA. Analysis of the first component changes using the thresholding method showed a decrease in ecological quality. So that the average RSEI index in 1989 was 0.57 and in 1397 this value reached 0.48, which indicates a decrease in RSEI. Also, the area of very good class in 1989 and 2018 is 32821.83 (16.267%) and 36879.66 (18.27%) hectares, respectively. Spatial variation analysis showed that the poor level of RSEI distributed mostly in the northern areas, and the ecological degradation was attributed to the fast expansion of the built-up area, characterized by increasing greatly in the value of the normalized differential built up index (NDBI) in such areas.
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In current study, we underlined the trends of annual precipitation over Iran in relation with changes in high and low extremes and normal values of precipitation from spatial analysis point of view. To this end, the third version of... more
In current study, we underlined the trends of annual precipitation over Iran in relation with changes in high and low extremes and normal values of precipitation from spatial analysis point of view. To this end, the third version of Asfazzari national database with 10 10 km spatial resolution and daily temporal resolution for 46 years (1970/3/21 to 2016/3/19) is adopted. Trend analysis depicted that in the major parts of the country (approximately 80.9%) the annual precipitation has experienced decreasing trends which tend to reducing about 1.5 billions cubic meters of input water in the hydrologic system of the country. Our finding showed that the decreasing trends of precipitation prompted by large scale and global systems. However, the local factors (longitude, latitude, elevation, slop) are culprits for changing the effects of abovementioned factors. These factors cause the decreasing trends to be statistically significant solely in a part of 33.53% of Iran territory (northeast, parts of eastern of Iran, parts of inner slops of Zagros mountain chain, an area from Kerman to Isfahan, Charmahal-o-Bakhtiari, Kohgiloyeh-oBoyerAhmad, from west of Shiraz, and north of Bushehr to Sanandaj in the west of Iran). Furthermore, the results of our study illustrated that the decreasing trends are due to decreasing in high values of precipitation, particularly decreasing in the 75th percentiles and above of precipitation values. The areas which include increasing trends covered spatially spread areas of about 2.93% of the country. This area has not been able to compensate for the lack of precipitation due to decreasing trends in the area associated with statistically significant decrease in precipitation.
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In this study we have used the daily mean data from the Modern Era Retrospective Analysis for Research and Applications version 2 (MERRA2) assimilated data. From the MERRA2 data, zonal wind and temperature were obtained at 10hPa from 01... more
In this study we have used the daily mean data from the Modern Era Retrospective Analysis for Research and Applications version 2 (MERRA2) assimilated data. From the MERRA2 data, zonal wind and temperature were obtained at 10hPa from 01 January 1979 to 04 June 2020.The temperature averaged around the polar cap for latitudes north of 60°N. This is a good measure of the overall temperature in the polar vortex. Investigation of the polar temperature and zonal-mean zonal wind at 10hPa, is detected 19 and 13 major and minor SSWs events, respectively. According to the shows a rapid increase from 201.6K on 12 January to 253.4K on 23 January 2009 (∆T=51.8K). This is the largest increase in the polar temperature per 11-day in the entire MERRA-2 data set starting from January 1979 to June 2020.
In this study life cycle of major SSWs is defined by dividing it into five periods. Onset (the first day of maximum zonal-mean zonal wind is reduced), growth (from onset day to zero day), maturation (from zero day to minimum zonal-mean zonal wind), decline (from minimum value to decay day) and decay (the first day of the easterly wind reversal to westerly) of typical SSWs. The result shows the shortest and longest growth periods, with 6 and 37 days, respectively, were recorded in the cases of January 6, 2013 and January 23, 1987. The longest maturation period, with 17 days of continuity, is dedicated to the warming of January 23, 1987. The longest decline period in this statistical period is 26 days, which is related to the warming of January 24, 2009. The shortest and longest life cycle in this statistical period are dedicated to cases on February 1, 2017 and January 23, 1987, respectively.
In this study life cycle of major SSWs is defined by dividing it into five periods. Onset (the first day of maximum zonal-mean zonal wind is reduced), growth (from onset day to zero day), maturation (from zero day to minimum zonal-mean zonal wind), decline (from minimum value to decay day) and decay (the first day of the easterly wind reversal to westerly) of typical SSWs. The result shows the shortest and longest growth periods, with 6 and 37 days, respectively, were recorded in the cases of January 6, 2013 and January 23, 1987. The longest maturation period, with 17 days of continuity, is dedicated to the warming of January 23, 1987. The longest decline period in this statistical period is 26 days, which is related to the warming of January 24, 2009. The shortest and longest life cycle in this statistical period are dedicated to cases on February 1, 2017 and January 23, 1987, respectively.
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Nebkha is a sand dune formed in many arid and semi-arid regions by the accumulation of sediments around vegetation. The appearance and development of the sand dunes can be a sign of the expansion of desertification. The interaction... more
Nebkha is a sand dune formed in many arid and semi-arid regions by the accumulation of sediments around vegetation. The appearance and development of the sand dunes can be a sign of the expansion of desertification. The interaction between wind performance and the geomorphic characteristics of sand dune leads to heterogeneity in the distribution of sediment particles within sand dune. The aim of this study was to investigate the effects of hydrological and aeolian processes on the morphology of nebkha. Overall, 9 sand dunes were randomly selected. For each nebkha, sediment sampling was carried out from the different positions, including upwind and leeward slopes, dune top, edge, and the interdune spaces. Data on the parameters of particle size distribution, hydraulic conductivity and moisture were extracted. The measured particles were classified to 5 groups, including clay (> 2 µm), fine silt (2-5µm), medium silt (5-20µm), coarse silt (20-64 µm), and sand (65≤ 2000 µm). The accumulation of aggregates with different sizes along the interdune-dune continuum could exhibit the contribution of hydro-aeolian processes in sediment transport and deposition. The findings showed that average aggregate size reduced from the interdune areas to the dunes, and the finest aggregates were observed on the dune edge, illustrating the functioning of hydrological processes on the evolution of the nebkha structure. By contrast, predominant sediments within the nebkha structure mostly were coarse-grained (sand) fractions, illustrating the functioning of aeolian processes. Based on the findings, the processes involved in the evolution of dune include the saltation and creep of sand-sized sediments, transportation of sediments through runoff in the interdune space, as well as sediment-laden runoff that flows from the top of coppice dune into the edge positions.
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The process of soil erosion as the central focus of soil and water conservation studies in sustainable ecosystems is influenced by various natural and human disturbances. Besides, the overall structure and composition of an ecosystem are... more
The process of soil erosion as the central focus of soil and water conservation studies in sustainable ecosystems is influenced by various natural and human disturbances. Besides, the overall structure and composition of an ecosystem are affected by changes in its landscape. Therefore, the present study was planned to investigate the relationship between landscape metrics and soil erosion patterns in the KoozehTopraghi Watershed located in Ardabil Province. In this regard, the 14 landscape metrics including Patch Density (PD), Largest Patch Index (LPI), Total Edge (TE), Edge Density (ED), Landscape Shape Index (LSI), Mean Patch Area (AREA-MN), Mean Euclidean Nearest Neighbor Distance (END-MN), Landscape Division Index (DIVISION), Mean Patch Shape Index (SHAPE-MN), Splitting Index (SPLIT), Patch Cohesion Index (COHESION ), Effective Mesh Size (MESH), Aggregation Index (AI) and Percentage of Landscape (PLAND) were calculated using Fragstats 4.2.1 Software. Then, the severity of soil erosion in the study area was estimated using the Erosion Potential Method (EPM), which its performance has been confirmed by previous studies around the study area. Then, the results of landscape metrics and soil erosion calculation were interred to IBM SPSS Statistics software platform, and the established regression models were determined. The results indicate an inverse relationship between DIVISION, ED, and LPI landscape metrics with the specific soil erosion and a direct relationship between SHAPE-MN and AREA-MN with specific soil erosion of the KoozehTopraghi Watershed. The results of the present study confirm the different behavioral patterns of land features as a result of land degradation processes. These results can be used in effective and sound planning of land use management at watershed and landscape scales.
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Floods are the most common natural hazards, the recurrence of which is increasing and the associated risks in urban and rural areas are of global importance, although their importance is not well understood for developing countries. The... more
Floods are the most common natural hazards, the recurrence of which is increasing and the associated risks in urban and rural areas are of global importance, although their importance is not well understood for developing countries. The aim of this study was to zoning the flood risk of Dinevar River in Kermanshah province. Therefore, the HEC_RAS numerical model was used to simulate the flood and was used through the HEC-GEORAS. Using SMADA software, the peak flow rate was calculated and the flood zone with different return periods of 2 years, 10 years, 25, 50, 100 and 200 years is simulated area and with the help of digital depth model Water and land use layer, the amount of damage was calculated using the equation of depth function and damage in the return period of 25 years, 50 and 100 years. The results of this study show that the area of flood expansion zone in the return period of 25 years is 40.34 square kilometers, in the return period of 50 years is 43.51 and in the return period of 100 years, 44.28 square kilometers is endangered in terms of damage. 25 years is considered a baseline flood that shows significant damage, covering all farms, but floods affect parts of farms at lower returns. But it is controllable, while 25-, 50-, and 100-year-old floods have completely endangered many rural centers and farms. 50 years has been an average of 85% more, which requires flood control for sustainable management.
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Land is one of the inputs of the production sector. It plays an important role not only in the agricultural economy and natural resources but also in the economy of the whole country and it is necessary to pay attention to the land and... more
Land is one of the inputs of the production sector. It plays an important role not only in the agricultural economy and natural resources but also in the economy of the whole country and it is necessary to pay attention to the land and the changes that have taken place in it. The present study was conducted to investigate the trend of land use change in Ojan Chay catchment using remote sensing and GIS. Multi-timer images of 1987 TM, ETM + 2002, and ETM + 2015 were used in this study, and land use maps were prepared based on digital processing of maximum probability and backup vector machine. The type of land use changes in the region was obtained. According to the results, the SVM method is more efficient for estimating land use changes in the study area so that the extracted results have a higher percentage of accuracy and kappa coefficient. From the results of evaluations, it can be deduced that the trend of land use change in some land uses such as agricultural lands and pastures is high. Agricultural lands have fluctuated from 33% to 37% over a period of 28 years and rangelands have decreased from 51% to 49%, with these two uses having the most changes. Finally, due to the fact that most of the changes in rangeland change have been related to agricultural lands and vice versa, therefore, the need to focus land management and improvement activities on this type of land use increases
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Floods are one of the biggest global problems, so with the increasing intensity and frequency of floods, global concerns about increased mortality and economic losses due to floods have increased. In this research, using geographic... more
Floods are one of the biggest global problems, so with the increasing intensity and frequency of floods, global concerns about increased mortality and economic losses due to floods have increased. In this research, using geographic information system (GIS), satellite images, synoptic station data, hierarchical analysis (AHP), and layer integration (WLC) method, flooding potential of Qarah_su catchment modeling Has been. The final flood risk map was prepared based on a combination of climatic and physical factors and elements, i.e., ten factors of vegetation, altitude, flood channel, geology, land use, rainfall, distance from the river, slope, soil, and drainage density. The weight of each criterion was used by the Analytic Hierarchy Process (AHP), and the weighted linear composition (WLC) method was used for spatial modeling and layer integration to prepare the flood potential map. The results of flood risk zoning showed that the 4th class as a high-risk category with 21.7% and the 5th class with a very high flood potential with 8.4%, more in the northern mountainous areas. And are located in the center of the region. In total, about 31% of the catchment area is covered by high to very high-risk flood areas, and because they have the most considerable role in runoff production, they should be given special attention in terms of watershed management. Classes one to three with low to medium flooding potential are located in low-lying areas, slopes, and plains of the center, south, and west of the basin and cover more than 69% of the area.