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Koohzad Raispour, Yones Khosravi,
Volume 7, Issue 2 (8-2020)
Volume 7, Issue 2 (8-2020)
Abstract
Abstract
Air pollution is one of the most important problems in many countries in the world, which, besides the environmental damage and human health, imposes many adverse social and economic impacts. Therefore, considering the vital importance of air and the rising course of increasing the contaminating agents in recent decades, it is necessary to study the elements and their pollutant gases in order to be aware of the existing situation and to adopt the necessary solutions. The phenomenon of atmospheric air pollution in Iran, as part of the world's atmosphere, is one of the goals of the industrial revolution, which has been increasing day by day as industrialization; population growth and urbanization have grown dramatically. Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is slightly less dense than air. In the atmosphere, it is spatially variable and short lived, having a role in the formation of ground-level ozone. Carbon monoxide consists of one carbon atom and one oxygen atom, connected by a triple bond that consists of two covalent bonds as well as one dative covalent bond. Carbon monoxide is produced from the partial oxidation of carbon-containing compounds; it forms when there is not enough oxygen to produce carbon dioxide (CO2), such as when operating a stove or an internal combustion engine in an enclosed space.
Carbon monoxide is one of the most dangerous air pollutants. Due to its importance, many techniques and methods have been used to monitor the Earth's atmosphere in recent years. as well as, the use of satellite data has become widespread because of the availability and availability of features such as spatial, temporal and spatial resolution. In this study, the data from Aqua / AIRS Carbon Monoxide data can be used to study the rate and trend of carbon monoxide gas changes in the atmosphere of the entire world, including Iran.The relevant data in NetCDF format, with one-day and 13.5 x 13.5km spatial resolution of during the 16-year statistical period (2003-2018), was extracted from ttps://disc.gsfc.nasa.gov/datasets/AIRS3STM_006 using ArcGIS software And Grads are processed, represented, analyzed.
The results indicate that the amount of carbon monoxide was reduced during the monthly and annual time series. Of course, monthly and seasonal variations have been impressive. Monthly, the highest concentration of carbon monoxide in January, February and March, and the lowest in August, September and October. Among the seasons, the highest and lowest levels of carbon monoxide were observed in the seasons of winter and summer, respectively. In spatially, the highest amount of surface carbon monoxide with an average of 150 ppb above the city of Tehran and the coastal area of the Caspian Sea and its lowest level with an average of 115 ppb on the Zagros heights was observed.
The results clearly show a clear picture of the dispersion of carbon monoxide gas in the horizontal and vertical direction of Iran's atmosphere. Based on the results obtained from the monthly carbon monoxide data collected during the statistical period (2003-2018), conducted in a three dimensional and regional area extending to the geographical area of Iran, The average surface carbon monoxide of more than 150 ppb above the Tehran metropolitan area and northern coast of Iran is less than 115 ppb on Zagros altitudes. Among other results, there are significant differences between the monthly carbon monoxide average in the surface troposphere of Iran, so that in the twelve months, the highest amount of carbon monoxide was observed in cold months and the lowest was observed in the warm months of the year, respectively. Seasonally, the highest level of seasonal carbon monoxide has been observed in winter and its seasonal season has peaked in summer. The results of vertical profiles (vertical aspect) of carbon monoxide changes in Iran's atmosphere in line with latitude and longitude indicate the maximum carbon monoxide concentration at lower levels of barley so that the maximum amount of carbon monoxide in the Iranian atmosphere is concentrated in the lower levels and Rarely exceeds the level of 250 hPa. Also, the results indicate that the rate of carbon monoxide emissions in the atmosphere of Iran has decreased, so that in the last years of the statistical period, about 30% of the amount of carbon monoxide in the atmosphere of Iran has been reduced, compared to the early years of the statistical period.
Key words: Air Pollution, Carbon Monoxide, AIRS, Remote Sensing, Iran.
Dr Hassan Lashkari, Miss Neda Esfandiari,
Volume 7, Issue 2 (8-2020)
Volume 7, Issue 2 (8-2020)
Abstract
Identification and synoptic analysis of the highest precipitation linked to ARs in Iran
Abstract
Atmospheric rivers (ARs) are long-narrow, concentrated structures of water vapour flux associated with extreme rainfall and floods. Accordingly, the arid and semi-arid regions are more vulnerable to this phenomenon. Therefore, this study identifies and introduces the highest precipitation occurred during the presence of ARs from November to April (2007-2018). The study also attempted to demonstrate the importance of ARs in extreme precipitation, influenced areas and identifies the effective synoptic factors. To this end, integrated water vapour transport data were used to identify ARs, and documented thresholds applied. AR event dates were investigated by their daily precipitation, and eventually, ten of the highest precipitation events (equivalent to the 95th percentile of maximum precipitation) associated with ARs were introduced and analyzed. The results showed that most ARs associated with extreme precipitation directly or indirectly originated from the southern warm seas. So the Red Sea, the Gulf of Aden and the Horn of Africa were the major source of ARs at the time of maximum IVT occurred. Synoptically, seven AR events formed from the low-pressure Sudanese system and three events from integration systems. The subtropical jet was the dominant dynamic of the upper troposphere, which helped to develop and constant of ARs. Moreover, the predominant structure of jets had a meridional tendency in Sudanese systems, while it was a zonal orientation in integration systems. The intense convective flows have caused extreme precipitation due to the dominance of strong upstream flow besides having the highest moisture flux. The station had the highest precipitation has been located in the eastern and northwestern region of the negative omega field or upstream flows.
Keywords: Identification and synoptic analysis, highest precipitation, Ars, Iran.
B Sharifinia Zahra,
Volume 7, Issue 2 (8-2020)
Volume 7, Issue 2 (8-2020)
Abstract
Evaluation and Evaluation of Resilience to Drought Hazards in Rural Areas Case Study: rural district Ghare Taghgan Neka
Extensive abstract
Concerns over the social, economic, and ecological impacts of climate change on human habitat have increased over the last few decades (McGranahan et al, 2007). According to the UN report, water shortages will occur in the near future in 18 countries, and by 2025 more than two-thirds of the world's population is projected to be in serious water shortages (Pozzi et al, 2013, 191 112; World Bank, 2008, 124). On the other hand, the number of disasters has increased over the past 20 years, reaching 400 from 200 accidents (Pittman et al, 2011, 83,94; Molen et al, 2011, 765-773). In this regard, droughts, the most dangerous natural disasters, affect a wide range of climates and ecosystems, and the geographical areas affected by them have increased rapidly in the last four decades (Kamara et al., 2018, 2318). Drought is a major threat to households and community’s dependent on agriculture for livelihoods (Anthopoulou et al, 2017). Because livelihoods in agricultural-dependent societies are more dependent on climate change (Pittman et al., 2017. (
It is central to the city of Neka; it requires a holistic perspective. The type of applied research and methodology used is descriptive-analytical. Librarian and field method (observation, questionnaire) were used to collect the required data. In order to assess the resilience of rural areas to drought in two economic dimensions (ability to return to employment and income generation and compensation of costs and losses) and in social dimension (awareness, knowledge, skills and preparedness and participation and Collaboration) Designed and developed a Likert-type questionnaire (¬1 very low, 5 = very high). The statistical population of this study is based on census of 6947 households in 24 villages with error of 0.07, ¬191 questionnaire as sample size and based on the relationship of sharing ratio of the number of samples in each village is specified and in villages less than 7 samples, the number has been upgraded to 7. Finally, 233 samples were used as the sample size based on questionnaire completion and analysis and were randomly distributed and distributed among households. To assess the validity of the questionnaire, the experts were first provided with validity and the validity of the research instrument was measured and the final indices and statements were extracted. The questionnaire developed at this stage was pre-tested in the study area and after confirmation of trust or reliability (Cronbach's alpha value of 0.84) the questionnaire was finalized for field research. Descriptive (inferential) and inferential statistical methods (single sample t, Friedman, cluster analysis) and VASP, ARAS and VIKOR models were used to analyze the data. Therefore, in order to evaluate and measure resilience in rural areas, firstly, annual moisture status was investigated based on SPI, SDI and GRI indices. Therefore, the moisture status of the study area during the 13-year statistical period (2006-2007) using the data of 9 Standard Precipitation Index (SPI) rain gauge data, the data of the discharge rate of 6 rivers Surface Flow Index (SDI) and the values Water level level of 9 piezometric wells of GRI index was calculated in DrinC software environment.
Iran's position on the dry belt and the persistence of droughts over the past two decades have led to the emergence of drought-related crises, especially for villagers who are heavily dependent on water for production, due to climate change. Droughts in the study area were also not exempt from this rule and resulted in adverse effects beyond the normal state and the risk of drought among rural farmers, which could be due to their low level of resilience to this risk. Be it. Therefore, the present study aimed to investigate the economic and social effects of this phenomenon on the status of rural resilience against drought hazards. The results showed that among the sample villages, in the economic dimension, the highest average belonged to Tavaza Abad village of Bostan Khel with average of 3.11 and the lowest average belonged to Plazhartesh village with average of 1.63. In the social aspect, the highest average belongs to the village of Dukhaelo with a mean of 3.54 and the lowest average belongs to the village of Plazhartesh with an average of 1.55. Also, the average real perception of the respondents is less than three and is moderately low, indicating that rural resilience to drought is low.
Keywords: Rural Areas, Resilience, Drought, Gharaghgan Village
Iraj Ghasemi, Fatemeh Razzzaghi Borkhani, Mohammad Ali Mohammadi Gharehghani, ,
Volume 7, Issue 2 (8-2020)
Volume 7, Issue 2 (8-2020)
Abstract
Natural disasters and rural displacement: contexts and consequences in Balouch Abad village
Abstract
Every year, a number of rural settlements are affected by natural disasters or human factors, in such a way that life in these settlements is dangerous, and even, in some cases impossible. Thus, displacement programs in the form of leaving the main settlement and creating new settlements in another place will be considered by planners and managers. These programs are not without consequences and affect different aspects of the residents' lives. Identifying these consequences can provide sufficient experience and evidence for managing other displacement projects. Accordingly, the current study focuses on displacement phenomenon in Balouch Abad village in order to identify the consequences of displacement by discovering the contexts of displacement and explaining the residents' perception about the causes of this phenomenon. In general, empirical literature on the topic shows that the consequences of displacement, both positive and negative, occur in all dimensions of human life, and that a change in any dimension can change other aspects of the life of the target community. Investigating all dimensions of displacement has been considered in a few studies, in which less attention has been paid to the existing contexts, perceptions and planning and management structures. Therefore, this study contributes to the relevant literature by querying these contexts and providing solutions for displacement programs in the future.
The aim of this study is to understand the perception of the residents of Baloch Abad village about the causes and consequences of residential displacement using a critical ethnographic approach. This approach is suitable for studying phenomena such as residential relocation, which are the result of the decisions of the planning system and in most cases is faced with the unwillingness and lack of interest of stakeholders (residents). In fact, the critical ethnographic approach seeks to examine inequality, conflict, and power in a subculture. Thus, the process of displacement due to integration with a kind of conflict between residents’ willingness and the planning system, can be well explained using this approach. Data was collected using in-depth interviewing, non-participant observation, and focus group techniques.
The experience of displacement in Balouch Abad village indicated that the consequences of displacement do not occur independently and are correlated with each other. In other words, the negative consequences in terms of social and economic are rooted in the physical- consequences, and on the other hand, the social consequences are also rooted in economic consequences. On this basis, the lack of attention to the proportion of housing based on social relations has been the prelude to occur other negative consequences. The mismatch between the structure and size of dwellings and their occupational requirements (animal husbandry) has led to the collapse of subsistence foundations. Evidence also showed that maintaining neighborly relations in the village was influenced by the physical structure and system of land transfer. As a result, it can be stated that the various consequences of residential displacement can occur through planning and physical management. This study is based solely on the evidence, contexts and perceptions of key stakeholders who are residents of Balouch Abad village; however, the part of the challenges of displacement in this village is due to managerial actions that were not considered in this study. Therefore, it seems that mere focus on the view of stakeholders is one of the main limitations of this study, which is necessary to pay attention to this limitation. In this regard, it has been tried to provide sufficient evidence on manures of management the displacement process through the technique of triangulation. Future studies may take into account the views of both experts and stakeholders at the same time.
Keywords: Residential displacement, Balouch Abad village, natural disaster, contexts and consequences of displacement.
Hamed Haidari, Dariush Yarahmadi , Mostafa Karampour,
Volume 7, Issue 3 (11-2020)
Volume 7, Issue 3 (11-2020)
Abstract
Dust phenomenon is one of the climatic fronts that is often formed in the dry and desert regions of the world, and is known as a natural hazard. Occurrence of walnuts causes dust, damage to the environment and the occurrence and exacerbation of respiratory, cardiac, air traffic and threats of tourism, agriculture and so on. Also, in the health section of the compounds in calcium dust, more than 2.5 g of it causes the appearance of kidney stones, and blood vessels. Iron causes swelling of the conjunctiva and retinal inflammation, as well as the syndrome. Magnesium causes depression, depression and dizziness of the individual. Short-term breathing of aluminum leads to coughing and irritation of the lungs and prolonged breathing causes damage to the lungs. In recent years, the identification of dust source areas has attracted the attention of researchers in numerous studies, and have introduced various areas around the world as the main source of generous production. The country of Iran, and in particular the Western and Southwestern logic of Iran, is constantly experiencing the phenomenon of dust and its problems. In the west of Iran, desert areas are located in the deserts of southern Iraq, Saudi Arabia and far away from Syria and North Africa. The geographic location of the southwestern part of Iran and its proximity to these deserts have led to a frequent occurrence of the phenomenon of dwarfs, which are different throughout the year.
In this research, two categories of data were used: the first group is data on climatic elements or unstable elements.
The annual climatic layers of the region were used for a 30-year statistical period of 2016- 2016. Measurement data on the temperature of surface temperature was obtained from a MODIS sensor in a 17-year statistical period (2000-2016). The second group of data layers and information on the ground factors or factors were stable. The layers of these variables included:
In this research, two categories of data were used: the first group is data on climatic elements or unstable elements.
The annual climatic layers of the region were used for a 30-year statistical period of 2016- 2016. Measurement data on the temperature of surface temperature was obtained from a MODIS sensor in a 17-year statistical period (2000-2016). The second group of data layers and information on the ground factors or factors were stable. The layers of these variables included:
- The digital elevation layer of the area with a precision spacing of 30 meters from this layer was used as the elevation layer of the area.
2. The slope of the region, in percent, which is the layer derivative of the digital elevation model and derived from the same specifications of the DEM layer.
3. The surface layer of the surface layer that was taken from the MODIS surface coating product
4. Layer of vegetation on the surface of the earth, which was also taken from the 1 kilogram MODIS vegetation cover
5. Soil layer that was prepared by the country's water and soil organization
The method of conducting analytical and statistical research in which the main objective is the determination of areas conducive to the formation or expansion of dust cores. In this regard, the establishment of land-based and climate databases is the first stage of work, after forming the required databases, the formation of information layers These data are in the GIS environment. In order to form these layers, the interpolated models in GIS were used and the optimal model was selected in such a way that less error values were obtained. After forming the existing layers, we classified and weighed each layer based on the AHP weighting algorithm. Finally, due to the assigned weights, the overlaying of the weights of the layers in the GIS environment was obtained and finally a potential capability map of the formation of local dust collectors in Lorestan province was obtained.
The rainfall factor is the most important and most important factor in determining the areas susceptible to becoming dusty. The weight of this factor in determining and identifying areas susceptible to dusty cores was equal to 239%. Vegetation factor, which was prepared using the NDVI indicator of the MODIS product, was the second factor in the development of dust-prone areas with a weight of 199.99. Relative humidity factor is the third factor or component that influences the determination of suitable areas to become the local focus of dust. The weight of this factor is equal to 0.15. The wind speed factor is in the fourth place in terms of determining the areas susceptible to dust. The relative weight of this factor is estimated at 116.0. As shown in Table 14, slope and elevation factors are the least important factors that can play a role in the production and development of dusty centers. The weight of these factors in identifying areas susceptible to formation of dusts is 0.024 and 032.2, 0 is detected. The calculated incompatibility index for this weighing is as high as 4.8, as shown in Table 15, which indicates that the contradiction between the offered weights of indices relative to each other is less than the allowed threshold (12).
Neutbay expressed the highest concentration of areas susceptible to dust mites in the eastern region, especially the northeast of the province, which includes the cities of Azna and Aligudarz. There are also parts of this category in the southern regions of the study area, including the cities of Poldokhtar and Rumshagan. In the central regions of the province as well as in the northwest of the province including the Khorramabad, Delfan, Dynasty and Dorood districts this class is not observed. In the southern parts of the city of Kohdasht, small parts of the floor of the potential centers of dust are also observed. This flooring has the most risk of becoming a dusty focus. The power source of many of the province's dusty incidents can also be said to be areas where some of them are currently potential sources of dust. Since they have played a major role in the identification and detection of these areas, rainfall and vegetation cover, these areas are exactly in line with parts of the province, which, firstly, have a mean rainfall of less than 250 mm, and the density of vegetation is less than 2 / 0 (NDVI index), which represents a very poor vegetation and, in fact, a lack of viable vegetation. In terms of land use, these areas, or inferior land, or very rangelands, are very weak.
The rainfall factor is the most important and most important factor in determining the areas susceptible to becoming dusty. The weight of this factor in determining and identifying areas susceptible to dusty cores was equal to 239%. Vegetation factor, which was prepared using the NDVI indicator of the MODIS product, was the second factor in the development of dust-prone areas with a weight of 199.99. Relative humidity factor is the third factor or component that influences the determination of suitable areas to become the local focus of dust. The weight of this factor is equal to 0.15. The wind speed factor is in the fourth place in terms of determining the areas susceptible to dust. The relative weight of this factor is estimated at 116.0. As shown in Table 14, slope and elevation factors are the least important factors that can play a role in the production and development of dusty centers. The weight of these factors in identifying areas susceptible to formation of dusts is 0.024 and 032.2, 0 is detected. The calculated incompatibility index for this weighing is as high as 4.8, as shown in Table 15, which indicates that the contradiction between the offered weights of indices relative to each other is less than the allowed threshold (12).
Neutbay expressed the highest concentration of areas susceptible to dust mites in the eastern region, especially the northeast of the province, which includes the cities of Azna and Aligudarz. There are also parts of this category in the southern regions of the study area, including the cities of Poldokhtar and Rumshagan. In the central regions of the province as well as in the northwest of the province including the Khorramabad, Delfan, Dynasty and Dorood districts this class is not observed. In the southern parts of the city of Kohdasht, small parts of the floor of the potential centers of dust are also observed. This flooring has the most risk of becoming a dusty focus. The power source of many of the province's dusty incidents can also be said to be areas where some of them are currently potential sources of dust. Since they have played a major role in the identification and detection of these areas, rainfall and vegetation cover, these areas are exactly in line with parts of the province, which, firstly, have a mean rainfall of less than 250 mm, and the density of vegetation is less than 2 / 0 (NDVI index), which represents a very poor vegetation and, in fact, a lack of viable vegetation. In terms of land use, these areas, or inferior land, or very rangelands, are very weak.
Zeinab Mojarad, Javad Jamalabadi, Najmeh Shafiei, Mohammad َali Zanganeh Asadi, Kobra Parak,
Volume 7, Issue 3 (11-2020)
Volume 7, Issue 3 (11-2020)
Abstract
Mass movements are among the morphodynamic phenomena that are affected by various factors at the level of the mountainous slopes. Massive movements and instability of the range are important hazards for human activities. Which often leads to the loss of economic resources and damage to property and facilities. These issues highlight the need for zoning the risk of mass movements as the first step in the proper environmental management of this phenomenon. In this research, we investigate the risk zone of mass movements using information estimation and surface density methods in the Watershed--ghochan-Shirvan Basin. For this purpose, at first, 12 important information layers affecting mass movements such as lithology, slope, elevation, rainfall, tide, erosion, climate, distance from the road, distance from fault, distance from the river, soil and land use, and digital They were. From the combination of operating maps with land surveys, the percentage of landslides in different units of each map was obtained. By calculating surface density, the information value of each factor was determined. Finally, a landslide risk zoning map was prepared by integrating different weight weights into two different information weighing models and a surface density model. The results of this study show that the southwestern part of the basin has the highest amount of landslide. Lithology is the most important element in the occurrence of landslides in the range. The surface density model is worth more than 12%.
Parisa Jaberi, Samaneh Sabetghadam, Sarmad Ghader,
Volume 7, Issue 3 (11-2020)
Volume 7, Issue 3 (11-2020)
Abstract
Visibility is one of the most important optical characteristics of the atmosphere. Prediction of visibility is essential for air pollution, air traffic, flight safety, road traffic and shipping. Visibility reduction may be caused by different reasons. Fog is one of the most common reasons of visibility reduction, i.e. the droplets of water suspended in the atmosphere reduce the visibility to less than 1 km. Precipitation may also reduce visibility. Prediction of visibility in NWP models is usually accomplished by using the relationship between visibility and liquid water content, temperature, relative humidity. Purpose of the present work is to predict visibility during fog and precipitation over Tehran area in January 11th, 2014 and March 7th, 2013. Different algorithms including UPP1, AFWA, FSL and SW99 have been experimented to predict visibility.. Predicted visibility has been compared to observations, including Synoptic and METAR data in Imam Khomeini and Mehrabad airport. The WRF version 3.8.1 has been used to simulate precipitation and fog. In this simulation model configuration defined in Lambert uniform space. The model consist three nested domains. First domain was a 27-km grid model (83×65), surrounding a 9-km grid model (112×94) which was surrounding a 3-km grid model (112×97). Center of all domains was at longitude 51° and 44' and latitude 36° and 5' which is located almost at center of Tehran. All domains had 40 vertical layers and model top was located at 100hPa. The out puts of 3-km domain is used for visibility estimation. Initial and boundary conditions were set by using FNL data which is 1°×1° degree grid data. This data is available every 6 hours. Simulations were in 36 hours and first 12 hours was the spin up time. Results show that most of these algorithms can partly predict visibility reduction. The FSL algorithm works better than the other methods in fog situation and SW99 works better in snow situation. Comparing results shows that the visibility reduction during snow is more reliable than during fog. There were some errors in model predictions some of them were due to visibility algorithms, because the coefficients of these algorithms were driven in other parts of earth. The other errors were systematic errors of WRF. Predictions of temperature had warm bias and also there were positive bias in prediction of relative humidity.
Kamal Omidvar, Mehdi Mahmodabadi, Parisa Shams, Mahbobeh Amiri Esfandegheh,
Volume 7, Issue 3 (11-2020)
Volume 7, Issue 3 (11-2020)
Abstract
Due to the fact that the mechanism of anticyclone Movements is the desire to descend and suppress the air, so the effect of these movements and their location in the occurrence of flood falls is significant. For this purpose, in this paper, flood precipitation in the last two decades of Kerman province was studied and two of the most severe ones were selected. Due to the emphasis of this paper on the province of Kerman, the heavy rainfall was calculated for each station in the province using the Gumble Type 1 Distribution Statistical Index. Then, the thermodynamic properties of the precipitation were analyzed using radial data and Kerman station's sketch diagram. For analysis of these floods, daily rainfall data of the synoptic station 10 of the province and sea surface pressure maps and850,500,300 hectopascal levels were used. Then, the arrangement of the simulated pattern and its trend in the air maps, were studied during a selective period daily3. The results of the study indicate that the main cause of flood precipitation in the study area is to strengthen the eastern Mediterranean landfall in the middle troposphere, so when moved downward to the bottom of the polar system, it is transmitted to lower latitudes As a result, Western systems, with their movements on the southern warm waters, have a high moisture content and cause heavy rainfall in the region. Also noteworthy in the occurrence of precipitation is the presence of intense swinging movements on the southern waters, especially the Oman Sea, which causes more humidity to be injected into the interior areas of the country and provides the conditions necessary for the occurrence of such rainfall.
Ali Mehrabi,
Volume 7, Issue 3 (11-2020)
Volume 7, Issue 3 (11-2020)
Abstract
Based on the correlation diagram between the master and slave images (Fig. 5), the pair of appropriate images in terms of the shortest spatial and temporal lines is identified to produce the interferogram. As shown in Fig. 5, the maximum vertical baseline is obtained between -400 and -400. The obtained interferograms indicate the cumulative phase of the study area, which fluctuates between zero and 2ᴫ. Using StaMPS method on interferograms, 650 points were identified and selected as permanent scatter points in the study area. As can be seen in Figure 7, the cumulative displacement of the permanent dispersant points varies from + 45 mm to -45 mm. The displacements occur in the direction of the satellitechr('39')s view so that the positive numbers Indicates surface approach to satellite and the uplift and the negative numbers indicate the surfacechr('39')s distance from the satellite and the subsidence. As shown in the figure, in the western part of the mine wall, areas of 100,000 square meters have been heavily subsided. The next area, which has high subsidence points, is in the eastern part of the mine wall with an area of 68,000 square meters. The third area is located in the northwestern part of the mine with an area of 17,000 square meters.
By measuring the amount of displacement of Persist Scatters points, the altitude changes occurred in the mining area. Based on the results, the altitude variation changes in the range of 45 mm to -45 mm per year. Accordingly, 3 subsidence area were identified in western, eastern and northwestern parts of the mine wall with an area of 100, 68, and 17 thousand square meters. Considering the importance of the subject and in order to prevent the destruction of the mine wall, more precise geotechnical studies are needed in these specified areas.
By measuring the amount of displacement of Persist Scatters points, the altitude changes occurred in the mining area. Based on the results, the altitude variation changes in the range of 45 mm to -45 mm per year. Accordingly, 3 subsidence area were identified in western, eastern and northwestern parts of the mine wall with an area of 100, 68, and 17 thousand square meters. Considering the importance of the subject and in order to prevent the destruction of the mine wall, more precise geotechnical studies are needed in these specified areas.
Reza Bayat, Mahmood Arabkhedri, Najmeh Behnam, Zahra Gerami,
Volume 7, Issue 3 (11-2020)
Volume 7, Issue 3 (11-2020)
Abstract
Soil erosion is one of the most important environmental issues in developing countries, including Iran that there is inaccurate information about its amount and distribution. For this purpose, the accuracy and distribution of erosion classes obtained from EPM and MPSIAC models as compared to BLM as ground truth values were evaluated in Shahriari watershed. First, the required data and information for MPSIAC, EPM and BLM models for basin erosion status was stored in a database. Then, using ARC/GIS9.3 software, erosion class maps were prepared based on each model formula and they have been intersected with the ground-truth map. Also a point map containing 1400 random points was also prepared for sampling the maps obtained from the models. Then, based on random sampling points map, each of the statistical indices of RMSE, RRMSE, MAE, MBE, NSE, CD, CRM and MSE were calculated. Also, to verify the spatial accuracy of the erosion class maps derived from the error matrix models and the Kappa coefficient of agreement, overall accuracy, producer accuracy and user accuracy. The results of the erosion of the models showed that the mean erosion intensity in MPSIAC model was 589 and in EPM model 287 m3/ km2.year that the basin erosion status is estimated to be moderate for the basin with the help of MPSIAC model and EPM model. The analysis of the above statistical indices shows that the RSME, MAE, MBE and MSE statistics in MPSIAC model have lower values. As a result, the MPSIAC model has less error than the EPM model. Overall, the results of the statistical indices showed that the MPSIAC model's erosion classes were more in line with the BLM output (as a ground truth map) than the EPM model. Also the kappa coefficient in MPSIAC is higher than in EPM model. Overall, the results show that the MPSIAC model erosion class maps overlap with the BLM model and in fact with the actual conditions of the area.
Zeynab Basiry, Noredin Rostami, Dr. Amin Saleh Pour Jam,
Volume 7, Issue 3 (11-2020)
Volume 7, Issue 3 (11-2020)
Abstract
The main purpose of the research is the identification and prioritization of criteria and indicators affecting on lack of sustainable participation of rural communities in combating desertification plans in Dehloran, Ilam province. To determine the number of sample villagers, 189 family were selected using the Cochran formula. In this research, after determining the effective indices and also indicators in the lack of sustainable participation, the questionnaire was designed and its validity was determined by the relevant experts. The reliability of the questionnaire was also tested and validated by calculating the Cronbach's alpha coefficient. Data were analyzed using AHP and Friedman nonparametric test. The findings of the research show that the results of prioritizing the indicators that affect the lack of stakeholder participation in the AHP based combating desertification plans from the experts' point of view, design-implementation, and educational-promotional criteria are the maximum and minimum priorities, respectively. The results of criteria ranking using the Friedman test in terms of rural residents also indicated that the economic criterion is placed in the first priority and design-implementation, social criterion and educational-promotional are in the next priorities, respectively. Likewise, the results of effective indicators ranking in the lack of sustainable participation of rural communities in combating desertification plans based on the Friedman test in term of the experts’ viewpoints indicate that “ignoring people's income as a direct incentive to implement combating desertification projects” are the most significant economic indicator. Similarly, in the compartment of executive design indicator, from the experts’ viewpoint “the lack of a comprehensive participatory management program to combating desertification” and from the viewpoint of residents of the village “the lack of attention to popular opinion in the design and development of projects are prioritized as the most important indicators. In prioritizing social indicators from the viewpoint of the experts “dependence of the villagers on the state power, distrust of the results of combating desertification plans as well as low literacy level” and in terms of villagers’ opinions, “distrust of the results of combating desertification plans, the dependence of rural residents on the state power, migration of youth” are introduced and prioritized as the most substantial indicators. In the educational-promotional criterion, in terms of both views “lack of training the residents of the area regarding combating desertification projects and the related purposes, as well as lack of utilizing the local promotional group”, are determined as the main important indicators.
Khabat Derafshi,
Volume 7, Issue 3 (11-2020)
Volume 7, Issue 3 (11-2020)
Abstract
In this study, the risk map as an index to define the said complexity was prepared in 5 categories of risk by combination of Tehran metropolis flood hazard and vulnerability maps. To analyze the risk varieties, the hydrological catchments of Tehran were extracted by Arc Hydro model and 12 catchments were selected. Using land use, roads network, and the percentage of residential floor area, bridges, altitude, slope and drainage density variables, the flood hazard map was calculated. Dilapidated urban blocks, population density, land use, bridges, slope and drainage density layers were used as variables which affecting the flood vulnerability. Covariance index was applied for matched variables and considering the locational coherence between the values of them. Based on the new raster layers, flood risk variability in Tehran metropolis as well as in each of the catchments were analyzed using stepwise regression model. Explanation of locational changes of risk between the catchments needs to calculate the weighted average risk and the independent variables in 12 catchments that obtained by zonal statistics. Based on these average values the factor analysis used to determine the varifactors or main components of the variability in flood risk between the catchments. Finally, fractal geometry models (perimeter-area and cumulative number-area) were used to demonstrate the chaos of the flood risk value in 5 categories of risk. According to the flood hazard zoning map of Tehran metropolitan area, the extent of high hazard zone is 129.6 square kilometers. High risk zone covers 28.6% of Tehranchr('39')s area, indicating that most of the citychr('39')s extents (174.4 square kilometers) are located in the high flood risk zone. After that, the moderate hazard zone is 28.5% of the city area. Very low zones with 3.53% of the total area are the smallest zones in the city, which are only 21.5 square kilometers. Overall, 78.3 percent of the total area of the city is located in the moderate to very high zones of flood hazard, reflecting Tehranchr('39')s challenge to flooding. The vulnerability map defines that 138 km2 of the Tehran city area is located in high and very high zones of the flood vulnerability. According to Tehran metropolitan flood risk zoning map, 163.1 km2 of Tehran city area is located in high risk zone which has the highest rate among flood risk categories in Tehran metropolis (26.9%).
Gholamreza Mohamadi, Dr Reza Borna, Dr Farideh Asadian,
Volume 7, Issue 3 (11-2020)
Volume 7, Issue 3 (11-2020)
Abstract
In the present study, the spatial-temporal analysis of the Arctic vortex and its role in the occurrence of heavy precipitation days in the Ghare-Su basin have been investigated. For this purpose, firstly, with the 95% percentile method, heavy precipitation days of the basin were extracted. Then, considering the pervasiveness condition, 79 days of heavy and pervasive precipitation days determined during the1979–2015. In the following considering the contour representative of the polar vortex in the geopotential height of 500 hPa maps, elevation maps of 500 hPa, the vortex position identified on each of the heavy precipitation days based on its maximum extent on the synoptic zone. Synoptic analysis of the temporal and spatial of Arctic vortex during the selection of heavy and pervasive precipitation days shows that the 4 patterns can be identified within 79 days of heavy precipitation days. The position and concentration of the vortex patterns in each season have changed. So that the least penetration of the vortex is seen during the autumn and the most penetration in the winter. In all cases of the days of heavy and pervasive precipitation due to the locating the trough of the arctic vortex over the study region, which coincides with the settlement of the huge Rex and Omega blockings on Europe. The highest correlation between the latitude of the vortex and the precipitation intensity is seen in the third pattern ( the Red Sea to the west of the Persian Gulf), which has the most vortex penetration in the region. In each of the vortex spatial locations, the location, length, and depth of the trough have also changed in each location. So that the best position and the most impact of vortex occurred in the third and fourth patterns where the troughs from vortex have the most depth and extension on adjacent water resources.
Alireza Kazemi, Behnod Barmayehvar,
Volume 7, Issue 4 (2-2021)
Volume 7, Issue 4 (2-2021)
Abstract
Due to the insecurity of the construction industry, the purpose of this study is to evaluate safety management and investigate its impact on reducing accidents of sites in urban construction projects in the south of Tehran. Due to the nature and type of research, the present study is descriptive-correlational and practical research. The statistical population in this study is supervising engineers working in the field of urban construction in the south of Tehran (15, 16, 17, 18, 19, and 20 areas). Therefore, according to the latest statistical report published by the Tehran Engineering System Organization (5000 people) and based on the Morgan table, 351 acceptable answer sheets were collected.
In this research, data collection and information were performed using the library-documentary method and field method (with the help of observation tools, interviews, and especially questionnaires) and through a combined method (quantitative-qualitative) with quantitative nature and focus as well as survey strategy. Also in this research, in addition to utilizing the capacities of qualitative content analysis, the methods of quantitative analysis include descriptive statistics including frequency, average, and standard deviation, as well as inferential statistics including Kolmogorov-Smirnov, Friedman, Pearson, T-tests and regression analysis by SPSS 24 software, was used. Questionnaire questions were validated by reviewing previous research, consulting with experts, and validating with factor analysis and reliability using Cronbach's alpha method.
The results show that among the three effective factors in improving safety management and reducing site accidents in urban construction projects in the south of Tehran, the factors of “use of protective equipment”, “compilation of responsibilities” and “risk management” with averages of 4.0864, 4.0741, and 3.9812 are ranked the first, second, and the third rank, respectively. Besides, the average part of various site accidents is 4.0000.
According to the results of the research, from the total types of site accidents of “injuries to people due to non-use of personal protective equipment”, “damage to urban underground facilities during nailing operation”, “life and financial losses due to standard and unsafe construction site equipment”, “occurrence of silent death in workers' rooms due to unsafe gas appliances and lack of proper ventilation, “collapse of structural parts during welding”, “fall of workers, materials, and equipment from a height”, and “collapse of the walls of the pit and adjacent plaques due to lack of standard and standard excavation” are ranked first to seventh with an average of 5.7692, 4.8148, 3.8490, 3.7322, 3.7236, 3.1282, and 2.9829, respectively.
According to previous research, the “policy (compilation of responsibilities)” factor has the first impact on the safety of the construction industry, but in a case where the field of research is limited to construction projects and urban constructions (personalization) in which in such projects safety management is not generally systematic in the site, the prioritization between the factors affecting the safety management of the site has changed and the “policy (compilation of responsibilities)” factor is transferred to the second rank and the “use of protective equipment” factor is placed in the first rank. Therefore, builders and employers, and that project supervisors must be required to closely monitor this carefully formulate safety responsibilities in construction workshops.
Considering that, the factor of “non-use of personal protective equipment” is in the first place as the cause of site accidents and has already been ranked in the fifth place of safety hazards, so it can be concluded that since the last decade, the factor of “non-use of personal protective equipment” has risen from the fifth to the first rank. Therefore, it is necessary to pay more attention to the use of protective equipment in construction sites in Tehran, project supervisors should be stricter in this regard, and engineering organizations and municipalities should enact stricter rules and regulations.
According to the supervising engineers active in the field of research, “damage to urban underground facilities during nailing method” is in the second place in the classification of common types of site accidents in the field of urban construction of Tehran and nailing method for stabilization of deep urban ditches causes legal problems to enter the privacy of adjacent license plaques and obtain notarized consent from the owners of adjacent license plaques, in addition to the risk of damaging underground urban facilities and causing heavy damage to the project and it is necessary to use other modern methods of deep pit stabilization, including the “Top-Down” method.
In this study, “human and financial losses due to non-standard construction site equipment” is classified in the third rank of site accidents. Therefore, the municipalities and organizations of the engineering system must make the issuance of technical inspection certificates for site equipment mandatory and if the employer and the constructor do not provide the necessary documents in this regard or to prevent the continuation of executive operations.
Because accidents due to non-observance of safety issues in construction sites continue to occur for various reasons, it is necessary to establish stricter rules and regulations regarding non-compliance with safety issues in construction sites in the field of urban construction and the use of a safety officer in the site with relevant educational and professional backgrounds and qualifications is mandatory for all construction sites.
The results of this study show that increasing attention and accuracy in the areas of responsibility compilation, risk management, and use of protective equipment improves safety management and reduces accidents in construction sites in the field of urban construction of south of Tehran.
In this research, data collection and information were performed using the library-documentary method and field method (with the help of observation tools, interviews, and especially questionnaires) and through a combined method (quantitative-qualitative) with quantitative nature and focus as well as survey strategy. Also in this research, in addition to utilizing the capacities of qualitative content analysis, the methods of quantitative analysis include descriptive statistics including frequency, average, and standard deviation, as well as inferential statistics including Kolmogorov-Smirnov, Friedman, Pearson, T-tests and regression analysis by SPSS 24 software, was used. Questionnaire questions were validated by reviewing previous research, consulting with experts, and validating with factor analysis and reliability using Cronbach's alpha method.
The results show that among the three effective factors in improving safety management and reducing site accidents in urban construction projects in the south of Tehran, the factors of “use of protective equipment”, “compilation of responsibilities” and “risk management” with averages of 4.0864, 4.0741, and 3.9812 are ranked the first, second, and the third rank, respectively. Besides, the average part of various site accidents is 4.0000.
According to the results of the research, from the total types of site accidents of “injuries to people due to non-use of personal protective equipment”, “damage to urban underground facilities during nailing operation”, “life and financial losses due to standard and unsafe construction site equipment”, “occurrence of silent death in workers' rooms due to unsafe gas appliances and lack of proper ventilation, “collapse of structural parts during welding”, “fall of workers, materials, and equipment from a height”, and “collapse of the walls of the pit and adjacent plaques due to lack of standard and standard excavation” are ranked first to seventh with an average of 5.7692, 4.8148, 3.8490, 3.7322, 3.7236, 3.1282, and 2.9829, respectively.
According to previous research, the “policy (compilation of responsibilities)” factor has the first impact on the safety of the construction industry, but in a case where the field of research is limited to construction projects and urban constructions (personalization) in which in such projects safety management is not generally systematic in the site, the prioritization between the factors affecting the safety management of the site has changed and the “policy (compilation of responsibilities)” factor is transferred to the second rank and the “use of protective equipment” factor is placed in the first rank. Therefore, builders and employers, and that project supervisors must be required to closely monitor this carefully formulate safety responsibilities in construction workshops.
Considering that, the factor of “non-use of personal protective equipment” is in the first place as the cause of site accidents and has already been ranked in the fifth place of safety hazards, so it can be concluded that since the last decade, the factor of “non-use of personal protective equipment” has risen from the fifth to the first rank. Therefore, it is necessary to pay more attention to the use of protective equipment in construction sites in Tehran, project supervisors should be stricter in this regard, and engineering organizations and municipalities should enact stricter rules and regulations.
According to the supervising engineers active in the field of research, “damage to urban underground facilities during nailing method” is in the second place in the classification of common types of site accidents in the field of urban construction of Tehran and nailing method for stabilization of deep urban ditches causes legal problems to enter the privacy of adjacent license plaques and obtain notarized consent from the owners of adjacent license plaques, in addition to the risk of damaging underground urban facilities and causing heavy damage to the project and it is necessary to use other modern methods of deep pit stabilization, including the “Top-Down” method.
In this study, “human and financial losses due to non-standard construction site equipment” is classified in the third rank of site accidents. Therefore, the municipalities and organizations of the engineering system must make the issuance of technical inspection certificates for site equipment mandatory and if the employer and the constructor do not provide the necessary documents in this regard or to prevent the continuation of executive operations.
Because accidents due to non-observance of safety issues in construction sites continue to occur for various reasons, it is necessary to establish stricter rules and regulations regarding non-compliance with safety issues in construction sites in the field of urban construction and the use of a safety officer in the site with relevant educational and professional backgrounds and qualifications is mandatory for all construction sites.
The results of this study show that increasing attention and accuracy in the areas of responsibility compilation, risk management, and use of protective equipment improves safety management and reduces accidents in construction sites in the field of urban construction of south of Tehran.
Zahra Keikha, Javad Bazrafshan, Sirous Ghanbari, Aleme Keikha,
Volume 7, Issue 4 (2-2021)
Volume 7, Issue 4 (2-2021)
Abstract
The occurred disasters in recent decades show that communities and people have getting incrementally vulnerable against the hazards. Therefore, social resiliency is the capacity of change, adaptation, and power of resisting against the social stresses and disasters. This research aims at the spatial analysis of the local community to have effective social indexes on resiliency against the environmental hazards in the Sistan region. The methodology of the research is applied due to its nature and descriptive-analytical with the quantitative-surveying approach based on structural equations modeling (SEM) due to its method. The statistical population of the research includes heads of households in 373 villages that 189 people were selected as a statistical sample in proportion to the population volume by Cochran formula using the stratified random sampling method. Inventory was used as a tool to collect data of research, and validity and reliability of tools were studied and confirmed by confirmatory factor analysis, and Cronbach’s alpha test and composite reliability, respectively. SEM method with partial least squares technical approach and SMART PLS3 software was used to analyze the research data in inferential statistics level. Findings of research showed that the path coefficients of social indexes relationship with social resiliency are significant based on t-value and p-value. In a way that t-value of this path is 11.28 and higher than its critical value, 2.58, and the p-value is lower than 0.05. In addition, WASPAS model was used for the spatial analysis of the effective social factors on the resiliency of the studied villages. This showed that villages of Zahak city have the maximum Qi and villages of Hamoon city have the minimum Qi. Thus, it is concluded that there is a significant relationship between the social indexes and the resiliency of the villagers. Moreover, the volume of the social index effect is high. Since villagers have higher Qi, they have more social resiliency. Hence, it is claimed that the villages of Zahak region have higher social resiliency.
Saeed Fathi, Ph.d. Ali Mohammad Khorshiddoust,
Volume 8, Issue 1 (5-2021)
Volume 8, Issue 1 (5-2021)
Abstract
Zoning and Spatial Analysis of Potential Environmental Hazards
Case study: Silvana District
Abstract
Natural hazards can be considered as one of the most important threats to humankind and nature that can occur anywhere in the world. Natural hazards are one of the main obstacles to sustainable development in different countries and one of the important indicators of the development of world countries is their readiness to deal with natural hazards. Therefore, it is important to pay attention to it and appropriate measures should be taken to reduce the vulnerability of human settlements. Nowadays with increasing population growth, population dynamics and the large number of people exposed to various types of disasters, the need to identify environmental potential hazards and identification of hazardous areas are felt more and more. Meantime, some people may not be aware of potential hazards of their place of residence. So by identifying and evaluating potential hazards and their Risks before the occurrence, we can significantly reduce the severity of the damages and contribute to sustainable regional development. The negative effects of natural disasters can be minimized by the availability of comprehensive and useful information from different areas and Multihazard mapping is one of the most effective tools in this regard.
According to the above mentioned, in this study, the spatial analysis of potential hazards in Silvana district in Urmia County has been studied. This study area due to specific geographic conditions such as position, complexity of topographic and ecological structures, in general, the existence of environmental factors for hazards has been selected as the study area. There have been a number of hazards in the past and assessing of this area is necessary, because of the lack of previous studies. For this purpose, by reviewing various reports and doing field observations, three hazards including Flood, Landslide, and Earthquake are identified as potential hazards of the study area.
For assessing hazards, 12 factors in 6 clusters such as Slope, Aspect (Topographic factors), Lithology, Soil type, Distance to Faults (Geological factors) Precipitation (Climatological factors), River Network Density, Groundwater Resources (Hydrological factors), Land use, Distance to Roads (Human factors), Observed Landslide Density and Seismicity (Historical factors) as the research factors has been selected. For weighting factors, Analytic Network Process (ANP) Method in Super Decisions 2.6.0 software environment has been used. The results of the analysis show that Slope (0.201), Precipitation (0.161), Lithology (0.112), Distance to Faults (0.106), Land use (0.096), Rivers (0.078), Seismicity (0.06), Soil Type (0.055), Landslide Density (0.047), Aspect (0.033), Groundwater (0.03) and Distance to Roads (0.016), Respectively have maximum to minimum relative weight. Then, weighted maps are standardized with using FUZZY functions. For this purpose, Fuzzy membership functions such as Linear, Large and Small has been selected based on each factor. For some factors such as Slope, Aspect, Lithology, Soil type, Rivers density, Land use, Seismicity and Landslide density, Fuzzy linear function has been used. For some others such as Groundwater and Precipitation, Fuzzy large function has been used and for distance to Faults and distance to Roads, Fuzzy small function has been used. Finally, weighted maps were overlay in ArcGIS 10.4.1 environment with Fuzzy Gamma 0.9 operator and potential hazards zoning maps is obtained.
Final results indicate that major parts in the Northwest, West and South of the study area located in high risk zones and 59 percent of the total area exposed to high risk. Based on hazard zoning maps, 44 percent of the area exposed to Flooding, 48 percent exposed to Landslide and 44 percent exposed to Earthquake. Also, 61 percent of the population or 37394 people exposed to one hazard, 7 percent or 3817 people exposed to two hazard and 8 percent or 4914 people exposed to three hazard. According to surveys, only 21 percent of the study area is considered as a low risk area but that does not mean that environmental hazards will never happen in these areas. In general, and based on results, it is concluded that Silvana district has a high potential for environmental hazards. Final results of the research show that potential hazards identifying and preparation of hazard zoning maps can be very useful in reducing damages and achieving sustainable regional development. Therefore, considering the ability of hazard zoning maps to identify areas exposed to risk and assess the type of potential hazards, These analyzes should be considered as one of the most appropriate and useful tools in different stages of crisis management that can be the solution to many problems in preventing and responding to natural disasters and therefore, it is recommended that they be used in the crisis management process.
Keywords: Spatial Analysis, Environmental Hazards, Silvana, ANP Method, Risk
Mr. Erfan Naseri, Mr. Alireza Massah Bavani, Mr. Tofigh Sadi,
Volume 8, Issue 1 (5-2021)
Volume 8, Issue 1 (5-2021)
Abstract
Detection and Attribution of Changing in Seasonal variability cause of climate change (Case study: Hillsides of Central Southern Alborz Mountains)
Abstract
One of the most important challenges for the human communities is Global Warming. This vital problem affected by Climate Change and corresponding effects. Thus this article attempted to assess the trend of real climate variables from synoptic stations. Daily precipitation, Daily Maximum Temperature and Daily Minimum Temperature have been selected for the Hillsides of Southern Central Alborz Mountains and have been tried to prove climate change and attribute the related forcing such as Greenhouse Gases. The Capital of Iran located in this region and this region has a special occasion, because at least a quarter of Iranian population live in these provinces (Tehran and Alborz) and four big dams located in this region. The Intergovernmental Panel on Climate Change’s defines ‘‘detection’’ of climate change as ‘‘the process of demonstrating that climate or a system affected by climate has changed in some defined statistical sense, without providing a reason for that change,’’ while ‘‘attribution’’ is defined as the process of evaluating the relative contribution of multiple causal factors to a change or event with an assignment of statistical confidence. Regional D&A studies provide an insight to local changes in natural systems and may help in planning and developing robust adaptation strategies. Previously, formal detection and attribution have been used to investigate the nature of changes in various climatological variables such as air temperature, surface specific humidity, ocean heat, sea level pressure, continental river runoff, global land precipitation and precipitation extremes. However, almost all of these studies deal with climatological or meteorological variables at the global or continental scale. Studies which have attempted to formally detect and attribute regional hydrometeorological changes to anthropogenic effects are rare. Regional-scale D&A analysis is more difficult because the detection of anthropogenic ‘‘signal’’ in natural internal climate variability ‘‘noise’’ is determined by the signal-to-noise ratio which is proportional to the spatial scale of analysis, especially for real observation data. For overcoming this issue interpolation method (IDW) has been applied to transfer point data to area (gridded) data. The point data gathered from 3 synoptic stations (Mehrabad, Karaj and Abali). Then transferred data have been Standard and Averaged for 3 years. Standard values of annual and seasonal amounts have been computed for individual stations as the average of the standard values of annual and seasonal amounts available 3 years anomaly values. Estimates of annual or seasonal variables anomalies were obtained by averaging the annual or seasonal by 12 or 3 respectively. For detecting and attributing 3 simulation signals (ALL, GHG and NAT) selected from Canadian General Circulation Model (CanESM2.0) of CMIP5 archive subcategories. Space–time series of observations and model simulated variables responses to external forcings (the “signals”) first have been compared qualitatively by computing correlation coefficients between observations and simulations. This simple method does not optimize the signal-to-noise ratio nor provide a quantitative measure of the magnitude of model simulated response relative to that in the observations. Nevertheless, it provides an easy-to-understand view of the similarity between observed and model-simulated changes. Optimal detection and attribution analysis very often requires a reduction of dimensionality. This is typically done by projecting both observations and simulations onto leading empirical orthogonal functions (EOFs) of internal variability and using the residual consistency check to determine the number of EOFs to be retained in the analysis. To produce internal variability for residual test and consistency, Pi-Ctrl Runs have been used. The Preindustrial simulations have high volume, this subject complicates calculation therefore Experimental Orthogonal Functions (EOFs) have been used to reduce the Pi-Ctrl simulations volume and provide situations for Optimal Fingerprint. Optimal Fingerprint method is the best method for Detection and Attribution. Results have been obtained by this manner indicated Global Warming affected the study region by affecting on mean cumulative winter precipitation (0.88), mean spring minimum temperature (0.78) and mean summer maximum temperature (0.76). These numbers are the beta coefficient that named scaling factor. Although the scaling factor for the mean spring minimum temperature affected from GHG signal obtained (0.73), but the GHG forcing alone didn’t have a significant effect on the precipitation and maximum temperature. Also, NAT signal didn’t have significant effect on the region alone, too. The obtained results of this study indicate the earlier studies, such as Wan et al, 2014.
Key words: Climate change, Detection, Attribution, Optimal Fingerprint, Hillsides of Central Southern Alborz Mountains
Mohammad Ali Zanganeh Asadi, Mahnaz Naemi Tabar,
Volume 8, Issue 1 (5-2021)
Volume 8, Issue 1 (5-2021)
Abstract
Relationship between hydrogeomorphic features and suspended sediment load under Kashfarud basins
Introduction
As a stressful stimulus, river sediment is the most significant threat to aquatic ecosystems. To prevent or minimize the damage, three stages of the erosion process should be investigated (Naseri et al., 2019: 83). Determining the amount of sediment transported by rivers is important from different aspects. Sediment carried by water flows is considered a factor effective in shaping the geometric structure and geomorphic characteristics of rivers (Tashekabood et al., 2019: 282).
Data and methodology
To estimate the amount of annual suspended sediments, the flow and sediment statistics of hydrometric stations (8 stations) and meteorological stations (13 stations) were employed (Figure 2). The research statistical period is 25 years (1993-2017). The altitude, area, and perimeter of the basins were obtained from topographic maps with a scale of 1.25000. To investigate the correlation between independent and dependent variables, the normality tests of Shapiro-Wilk and Kolmogorov-Smirnov were performed in SPSS16 software. To extract the geomorphic features of the basins, the digital elevation model was used. Then, ground surface corrections and pretreatments such as removal of hydrological pits were performed and ground drainage pattern was determined.
Stepwise multivariate regression
In the present study, stepwise multivariate regression was used to reduce the number of independent variables and determine the effective factors in the sedimentation of the basin. This method investigates the effect of several independent variables on a dependent variable (Zare Chahuki: 2010). In stepwise multivariate regression, the independent variable that has no more significant effect on the dependent variable is removed from the analysis, hence excluded from the equation. The general form of the stepwise regression equation is:
Equation 1 Y= a + B1X1 + B2X2 + …… + BnXn + e
Data description and interpretation
The principal component analysis method was used to determine the most effective characteristics of sediments as well as their grouping. In principal component analysis, variables that have a high correlation and are distributed in a multidimensional space are reduced to a set of non-correlated components, each of which is a linear combination of the main variables. The obtained non-correlated components are called principal components (PCs). Prior to component analysis, the KMO coefficient was used to ensure the appropriateness of the data for principal component analysis. This coefficient fluctuates in the range of zero and one and if its value is less than 0.5, the data will not be suitable for principal component analysis and if the values of this coefficient are between 0.5-0.69, The proportionality of the data is moderate and if the value of this coefficient is more than 0.7, the data will be quite suitable for performing principal component analysis.
Regression analysis results
In this study, the sediment weight of the basin was considered as a dependent variable and other parameters as independent variables. The variables of slope, precipitation, basin length, Elongation Ratio (R), circularity coefficient, and unevenness of the basin have a higher correlation with the amount of sediment production in the basin than other variables.
An eigenvalue was used to determine the number of factors. The minimum eigenvalue for the selection of final factors is 1, and factors with an eigenvalue bigger than 1 are considered final factors. The results showed that the three factors of circularity coefficient, compactness coefficient, and basin form coefficient have an eigenvalue bigger than 1.
Conclusion
The results showed that geomorphic parameters have a high correlation with the amount of annual sediment. The results showed that seven factors of slope, precipitation, basin length, elongation ratio, circularity coefficient, unevenness coefficient, and form ratio of the basin were the most important in estimating the amount of suspended sediment based on the principal components analysis method. The average of special sediment varies from 134 tons per year in Dehbar basin to 16 tons per year in Kardeh basin and also the average annual sediment varies from 261.6 tons per year in Golmakan basin to 156.7 tons per year in Shandiz basin. Evaluation of Bartlett's test of sphericity tests and KMO values is 0.9. Therefore, the data is suitable for factor analysis. The percentage of variance explained by each factor indicates that the circularity coefficient with 50.71% of the variance explains all the research variables. In total, three factors of circularity coefficient, compactness coefficient, and form ratio of the basin could explain 82.6% of the variance of all research variables. Therefore, the results are consistent with Lu et al. (1991), Sarangi et al. (2005), Tamene et al. (2006), Zhang et al. (2015), Salim (2014), and Ares et al. (2016).
Khorram Dareh sub-basin with heavy rainfall (504 mm) has the lowest specific sediment, which is due to the geological structure of the region. Based on the calculated indicators, most of the studied sub-basins are elongated. The form ratio of the basin is less indicative of the elongation of the basin. The highest branching ratio of the basins is in the vicinity of faults. Also, high circularity values indicate points prone to sedimentation. River sections up to degree 3 are located in more subdued areas and have a steeper slope. Golmakan, Khorram Darreh, Zashk, and Dehbar sub-basins have a high potential for sedimentation. Regression equations of sediment measurement curves are usually used in sediment load estimates. The most important reason is the ease of application of these equations. According to the research results, it can be concluded that the integrated use of principal component analysis, cluster analysis, and multivariate stepwise regression has a suitable and acceptable efficiency in estimating suspended sediments. Testing the regression model concerning different climatic and hydrological regimes of Iran’s watersheds to achieve an efficient pattern of using these equations can be fruitful in estimating sediment load in different regions.
Keywords: Hydrogeomorphic, Sediment erosion, Kashfarud basin, Stepwise multivariate regression
Mohammad Javad Barati, Manuchehr Farajzadeh Asl, Reza Borna,
Volume 8, Issue 1 (5-2021)
Volume 8, Issue 1 (5-2021)
Abstract
Evaluation of SADFAT model performance in daily forecast of Land Surface Temperature in the city of Tehran
Abstract
The high spatial and temporal limitations of TIR images for use in urban climatology have been identified as a current scientific challenge. Therefore, the use of Data Fusion Algorithms in Remote Sensing has been considered. In the old methods, two bands of one sensor were used for Data Fusion. In these methods, a panchromatic band was used to increase spatial accuracy, so only spatial resolution was increased. To solve this problem, the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) was used to integrate the images of two Landsat and Modis gauges to increase the spatial and temporal resolution of the reflection. but, this algorithm is designed for pixels and unmixing areas that are the same in Modis and Landsat pixels. The use of this model was not suitable for urban areas with a different of landuse. Therefore, the Enhanced STARFM model (ESTARFM) was developed. The ESTARFM model was improved in 2014 to predict thermal radiation and LST, taking into account the annual temperature cycle and the unevenness of the earth's surface, and the SADFAT model was introduced.
In this study, the performance of SADFAT model in the use of OLI spatial resolution and MODIS temporal resolution in LST forecast in urban areas was examined. The metropolis of Tehran has different surface covers and multiple microclimates. So if the algorithm works successfully, This model can be used in other cities to improve urban heat island studies. The inputs for the algorithm are thermal radiance of Modis and Landsat images, the red and near infrared band of Landsat for daily production of LST in 2017 in the city of Tehran. The algorithm uses two pairs of Modis and Landsat images at the same time and sets of Modis images at the time of prediction and then calculate the conversion coefficient for relating the thermal radiance change of a mixed pixel at the coarse resolution to that of a fine resolution. In this way, LST is generated in areas with a variety of landuse.
All the estimated pixels were compared to the base image pixels in that range to evaluate the results of the model. The comparison results for the autumn days with the average correlation coefficient of 0.86 and RMSE equal to 0.122, showed that the model has the highest accuracy in this season and in other seasons with the average correlation coefficient of 0.76 and RMSE about 0.4, has provided good accuracy.
Visual interpretation of the results of SADFAT showed that this model is able to accurately predict the LST of the land cover in different surface coatings and even in areas where one or more urban land uses are mixed in one MODIS pixel.
However, the borders are well separated and the features are not combined. Although the boundaries are clearly defined, in some land uses, the predicted LST is somewhat higher than the observational image.
Landsat and Modis satellites pass through an area with a small time difference, so they are suitable for combining with each other. But in predicting reflectance with the SADFAT algorithm, there are systematic and variable errors that we need to be aware of in order to increase the output accuracy. One of the systematic and unavoidable errors is the instability of the Terra and Aqua satellites passing through at any point, ie at each satellite pass, the location of the study area in Swath and the size of the pixel changes. Due to the distance of the study area from the vertical center of measurement on the ground (Nadir), the amount of this error varies on different days and should be checked for each day. The preventable error is the sudden change in one or more images used (16 days of the same pass time interval for Landsat) is high for estimating surface reflectance with spatial and temporal resolution. These changes may be due to human factors such as air pollution or natural factors. Natural factors such as clouds and dust storms are the main sources of error in using the SADFAT model because they are sudden and temporary and cover a wide area. The occurrence of these two factors has a great impact on reflectance. Therefore, a sudden change in these factors, in one or more images, causes a large error in the calculations.
The study also found minor spatial errors in the prediction, so that even on days when the results were better, points were observed where the values in the predicted LST images did not match exactly with the OLI sensor. The reason for this may be due to changes in vegetation. Although there are some systematic and variable errors in the images and the implementation of the algorithm The results of this study showed that the performance of this model is reliable for predicting the daily LST with a spatial resolution of 30 meters in Tehran.
This method is able to support urban planning activities related to climate change in cities, so it is recommended that its performance be examined separately for different land cover in the city and the efficiency of this algorithm be evaluated with other sensors such as Copernicus Sentinels.
Key words: Spatial and Temporal Data Fusion, SADFAT, Heat island, LST, Urban climatology
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Mr Mohammad Hossein Aalinejad, Pro Saeed Jahanbakhsh Asl,
Volume 8, Issue 1 (5-2021)
Volume 8, Issue 1 (5-2021)
Abstract
Simulation of runoff from Gamasiab basin snowmelt with SRM model
Abstract
Snow cover in a basin affect its water balance and energy balance. So, snow cover variation is a major factor in climate change of a region. Study of temporal variation of snowmelt and snow water equivalent depth is very important in flood forecasting, reservoir management and agricultural activities of an area. In the most of the mountainous basins of the country, information on snow cover were not available. Also, the number of meteorological stations in high altitude areas do not match with information needed for snowmelt simulation. Therefore, indirect methods such as the analysis of satellite images to obtain the needed parameters for simulation is necessary, which is the one of the most effective methods in estimation of runoff originated from snow. Using the NOAA satellite data for zoning the snow cover of area started firstly in the USA since the 1961 and continuous until today (spatial and temporal resolution of satellite images increased by starting the MODIS work).
Gamasiab River is one of the important branches of Karkheh basin. Its basin area is about 11040 km2 between latitude 47 degrees 7 minutes to 49 degrees 10 minutes east and latitude 33 degrees 48 minutes 4 degrees 85 minutes north. The altitude of this basin is 1275 to 3680 meters above sea level. In this study, for simulation of runoff originated from melting snow, firstly snow cover in the basin of Gamasiab in 2014 to 2017 calculated by using the satellite images of MODIS in the google earth engine system. Also, air temperature and precipitation data of synoptic stations in the area of study and daily stream flow discharges of Polechehr hydrometric station, from November of 2014 to July of 2017 was used. Then, weather and snow cover area included as the input of SRM for simulation of snowmelt runoff. To obtain the information needed to the model, physiographic characteristics of the basin including the area and different classes of height obtained from the Arc-Hydro and Hec_GeoHMS in DEM maps of GIS software. Then the snow cover areas obtained from the images of MODIS in daily interval that obtained by google earth engine system.
Using the digital elevation map (DEM) and the accession of the Arc-Hydro and Hec_GeoHMS software of GIS, firstly flow direction map plotted. Secondly flow accumulation and stream flow network maps plotted, and by introducing the basin output to the program (Polechehr hydrometric station) borders of the basin identified and classification of the basin accomplished according to the three distinct height classes. Monitoring the snow surface cover during the daily time interval showed that the area covered with snow in winter season. This area decreases as the air temperature increases. The SRM model simulated the snowmelt of Gamasiab basin with good accurately, in which, the percent of volume error or Vd was lose than 2% and the R2 was above 0.9.
The results of this research showed that the using the images of MODIS yields a reasonable estimation of the snow cover area of Gamasiab with local of data. Also simulation results showed the high capability of the SRM in snowmelt runoff of the area under study. Result showed that the coefficient of determination and volume percent of error of model was 0.93 and %0.3 for 2014-2015 and it was 0.9 and 3.33 for 2015-2016 years, respectively. The results of this study, was in consistent with the previous studies fading in which in addition of model's parameters, physiographic characteristics, basin play a major role in the accuracy of the simulation. According to the calculated and observed runoff diagram, in both years of study, peak temperatures begin in March, as the weather warms and the snow melts, and will continue until April. Considering the snow cover, it can be concluded that the main runoff of March Peak is related to snowmelt, but with the change in the shape of precipitation from snow to rain and the warming of the weather, April peak is related to rain. Regardless of acceptable simulation results of the model, the lack of snow survey station in the study area, (yield the model to face with difficulty) in process. To overcome this shortcoming, we used the presumptions of the model and recommended values of the model.
Keywords: MODIS; Remote sensing; Runoff Snow; SRM; Gamasiab.
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