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Showing 25 results for Dust
Nasim Hossien Hamzeh, Ebrahim Fattahi, Mjtaba Zoljodi, Parvin Ghaforian, Abbas Ranjbar,
Volume 3, Issue 1 (4-2016)
Volume 3, Issue 1 (4-2016)
Abstract
Dust particles consist of important aerosols and resulting in blowing strong winds on the surface of desert areas. These particles enter the atmosphere under the influence of different factors including: weather condition (wind, precipitation and temperature), land surface (topography, humidity level, roughness and vegetation), soil features (texture, density, composition and land use (agriculture).
Today powerful dust storm destroys people lives and causes severe damages to their life and also causes financial problems in most regions of the world especially in west and southwest of Asia. Dust storm is one of the most important natural phenomena and also a kind of severe natural disaster that influence Iran and its west and southwest part. The location of Iran on the desert belt is accompanied by frequent increasing of sand and dust storm. Integral prediction of dust storm phenomena can be useful in decreasing damages caused by these storms. So synoptic-dynamic analysis of dust storms and their simulation play an important role in achieving to this goal.
In this research, we investigate severe dust storm in August 2005 that affected a large area of our country. Select of dusty days were based on minimum visibility and maximum durability of that dust storm. At first, we show the minimum of daily visibility table. These data has been provided by Meteorological Organization in 5 western cities. The synoptic maps were related to these phenomena derived from NOAA website and synoptic and dynamic interpretation has been done. We have got the data with resolution of 2.5 degree from NOAA website.
Then 700 hpa relative vorticity maps were drawn. We investigate MODIS images instrument on Aqua satellite and evaluate the amount of mass concentration of dust particles. Then the Lagrangian Integrated Trajectory Model has been used to determine the backward trajectory of dust particles. We run HYSPLIT model by GDAS data with a resolution of 0.5 degrees. At last we investigate the output of the WRE-CHEM model. This model was run to simulate dust storms in 7-10 August and FNL data with a resolution 1 degree use for initial and boundary conditions. WRF-CHEM is used to simulate dust condition and transmission. As a part of WRF model, its main application is the study of atmosphere chemistry.
At 500 hpa a very strong ridge entered Iran from the southwest. It covered all areas of our country which prevents the transference of dust to high levels of atmosphere. In 700 hpa relative vorticity maps show one day before dust storm reach to Iran a Positive voriticity is located in Iraq and Syria. So dust comes up to higher levels of the atmosphere and in dusty days in our country. There is a negative voriticity located in our country and because of downside movement of the air, dust storm happen in Iran.
Dust loading and friction velocity of outputs of the model has been drawn in dusty days. The time series of dust concentration of output models for Tabriz are compared with the concentration data of Environmental Organization of visibility data. Result show that a low pressure system is located over the Oman sea that its blaze has been extended to the northwest of Iran. On the other hand a high pressure center is located in the Europe that extended to the east of Mediterranean. So strong pressure gradient were in Iraq and Syria and they caused the creation of strong winds in their deserts which caused dust emission.
Friction velocity related to the model outputs show that the velocity of wind is high in dusty days in Iraq and Syria. So conditions are suitable for dust raining. Satellite images showed that WRF/CHEM model is simulated very well in emission, source, diffusion and the extent of the areas covered with dust. Comparing MP10 concentration of the model output with and Environment Organization data of Tabriz city show that WRF/CHEM model forecast daily changes well. But model underestimate significantly in quantity of concentration. This error may be due to a model considering only dust quantity but other pollutants affected on visibility. In general it can be said that in this event, dust concentration has been underestimated by WRF/CHEM model especially in maximum amount of PM10 concentration.
Behroz Nasiri , Zahra Zareei Chaghabalaki, Mansour Halimi, Mohammad Rostami Fath Abadi,
Volume 3, Issue 2 (5-2016)
Volume 3, Issue 2 (5-2016)
Abstract
One of the most important components of the extent of pollutants mixing and air quality at near the Earth's surface is the height of boundary layer. Many variables involved in determining the height of the boundary layer of atmosphere. Although all of the troposphere (the lower ~10km of the atmosphere) is affected by surface conditions, most of it has a relatively slow response time. The lower part of the troposphere that is affected on a shorter time scale is commonly defined as the Planetary Boundary Layer (PBL). The depth of the mixed layer has a significant effect on the concentration of air pollution, which itself is dependent on the intensity and duration of solar radiation and wind speed. According to Stull, one can describe the planetary boundary layer as “that part of the troposphere that is directly influenced by the presence of the earth’s surface, and responds to surface forcing with a timescale of about an hour or less.” Surface temperature has a strong relationship with height of the PBL. As the surface cycles between daytime radiation and nighttime cooling the amount of convection taking place changes. When the temperature gradient is steep, more convection takes place to dissipate thermal energy in the most efficient manner. In other words, the greater the temperature difference between the surface and the lower troposphere, the higher convective eddies must reach to alleviate the gradient. Relating this to Stull’s definition of turbulence, it can be concluded that the height of the PBL varies with surface temperature. In fact, the spatial range of the PBL can vary from less than one hundred meters to several kilometers. The strong relationship between convective turbulence and height of the PBL is sometimes used to define the boundary layer and call it the Convective Boundary Layer (CBL). Analogous to the Stull’s definition but focusing on turbulence, Lloyd et all describe CBL as “a layer of air typically of order 1km in depth, well mixed by turbulence maintained by buoyancy due to heating at the ground. It is bounded above by stably stratified, no turbulent air and grows through the day. In this study we aimed to analysis the status of ABL in 3 dust period days in Khuzestan province of Iran.
The Data were used in this study includes: The Daily data of dust concentration during 27Jan to 1 Feb 2015, the daily height of ABL also were used. The daily data of ABL were given from ECMWF with 1/8 degree spatial resolution. We used the Pearson correlation and synoptic analysis to assessment the condition of boundary layer at the mentioned days. For analysis the characteristic of ABL the climatic data of Wyoming University were used to assessment the thermodynamics of atmosphere. The spatial distribution of ABL height at the dusty day also were used for 12 UTC.
The results indicated there is the direct relationship between the ABL height and the concentration of dust in the mentioned days. So that in the days that the concentration of dust reaches maximum we fund that the height of ABL reaches maximum simultaneously and vis versa. The spatial distribution of ABL height shown that the height of ABL in the 29Jan reaches maximum that the maximum concentration of dust related to this day. And also the minimum concentration of dust observed in 27Jan and 1Feb that the in this day the height of ABL was minimum. The synoptic analysis also reveals that locating the low pressure system at the 500hp level that the Khuzestan province has been locating at the front of this system lead to transport the dust to study area.
In this study we reveal that the height of ABL in the dust days of Khuzestan has a totally revers behavior in compare to the air pollution days in Tehran. In the pollution days in Tehran the lowing of ABL height and inversion lead to intensify the concentration of pollution while in the dust days of Khuzestan the height of ABL were increased in compared with non-dusty days.
Miss Elham Karegar, Javad Bodagh Jamali , Abbas Ranjbar Saadat Abadi , Mazaher Moeenoddini, Hamid Goshtasb ,
Volume 3, Issue 4 (1-2017)
Volume 3, Issue 4 (1-2017)
Abstract
Dust particles are important atmospheric aerosol compounds. The particles are resulting performance of strong winds at the soil surface desert areas. Sources of dust are 2 types: 1- Natural Resources 2- Human Resources. Iran is located in the desert belt which this problem cause increased the frequency of dust storms, especially in South East (Sistan) and South West. China Meteorological Administration Center classifies storms based on particles type, visibility and speed storms to 4 kind: Floating Dust, Blowing Dust, Sand/Dust Storm and Sever Sand/Dust Storm. In general, the effects of dust storms in 7 of Environment (particles into remote areas, the effect of dust particles on the material, climate, oceans and deserts), public health and health (increase of respiratory diseases , cardiovascular problems, digestive, eye, skin, reduced hearing, infections, reduced life expectancy and premature death, etc.), economic (unemployment, road accidents, damage to communication lines, air, land, sea, increase water turbidity in water utilities, creating uncertainty for all economic activities, etc.), Agriculture and Livestock (negative effect on the growth of plants and animals, reduced productivity and diversification, intensification of plant and animal pests and diseases, rising costs maintenance of livestock, etc.), socio-cultural (poverty and the loss of local jobs, destruction of subcultures, rural migration to the cities, closure of educational premises, industrial units, services, etc.) and military-security (disabling weapons, food and beverage contamination, the threat of sensitive electronics and power transmission systems, and reduce the useful life sitting on warehouse equipment, logistics cargo weight gain, etc.) can be evaluated. One way to identify, evaluate and forecast dust storm modeling. Dust cycle consists of 3 parts, dust emissions, dust and subsidence transfer dust that can be simulated by models.
In this study using the WRF_Chem model with FNL[1] input data and GOCART schema, sever dust storm in Sistan region was simulated to date 14 & 15 July 2011. Satellite images of the event was received by the MODIS sensor. Dust concentration data was received from the Department of Environment. The dust storm code, minimum visibility data and maximum wind speed data was received from the, Meteorological Organization.
The results of the simulation for dust concentration which peak amount of dust was for 21Z14July2011 and 03Z15 July 2011. Model output showed maximum wind speed 20 m/s with North to South direction in the study area. The model predicts maximum dust concentration for the latitude 31 degree North and longitude 54 degree East to 66 degree East (Within the study area). MODIS sensor images showed clearly the sever dust storm. Simulated time series in Figure 3-1 Changes in dust concentration during the event show in the Sistan region. As can be seen from the peak of the concentration of dust in 21 hours on 14 July (350 micrograms per cubic meter) and 03 hours on 15 July (425 micrograms per cubic meter) 2011 was created. Model simulation and satellite images indicated which the Sistan region, especially dry bed of Hamoun wetland in East of Iran was main source of sand and dust storm. Also, based on the model output blowing wind direction from North to South on Iran which converging these currents in East Iran caused by strong winds in the lower levels (According to the meteorological data), arise dust, increasing the dust concentration (According to Department of Environment data), increasing the dust and being transferred to the Southern regions, especially Oman sea. To identify the source of the sand and dust storm, the path of the particle and anticipated this event cant actions and warned to stop and reduce effects its. . Simulation of dust particles in the resolution of 10 and 30 kilometers, the plains of Sistan in Iran's East region as the main source screen. The findings suggest that compliance with the maximum concentration limits on known sources of particles (especially Sistan plain dry bed of plain wetlands) is. Check drawings wear rate showed that the source of dust in the Sistan region, particularly the high potential of our wetlands dry bed of soil erosion in wind activity 120 days during the hot and dry conditions, and silt and clay up to thousands of kilometers away from their source transfers. Vector lines on maps wear rate, indicative of converging flow north-south and severe dust storms in history is this. It is better than models forecast dust events and rapid alert
[1] Final Reanalysis
Mr Seyed Abdolhossein Arami, Professor Majid Ownegh, Dr Ali Mohammadianbehbahani, Dr Mehri Akbari, Professor Alireza Zarasvandi,
Volume 5, Issue 1 (6-2018)
Volume 5, Issue 1 (6-2018)
Abstract
The analysis of dust hazard studies in southwest region of Iran in 22 years (1996-2017)
Dust storms are natural hazards that mostly occur in arid and semi-arid regions and there are many harmful consequences. According to the topographic-climatic conditions in Iran and the significant increase in the number and severity of dust storms occurrence in recent decades, especially in the West and Southwest regions where the dust storms are the most important environmental crisis. Studying this phenomenon is necessary for better management its harmful effects.
Since most of the research are implemented as different case studies, and there is no comprehensive study that review a wide range of existing researches with overall results in the southwestern parts of Iran, in this study a comprehensive overview of available literature reviews are addressed including dust spatio-temporal variations, modeling, detection, and health issues.
This research is based on a library research and search of valid national and international scientific articles about the dust crisis and no data-processing. We attempted to analyze temporal and spatial variations in the south and southwest of the country using the available studies and the challenges of this phenomenon in the past and present to provide a new perspective to apply a comprehensive land management and managing environmental hazards in Iran with all the problems.
A review of the history of dust storm studies from information sources showed that most researchers (61.40%) used a synoptic method to study dust storms, and the most important indicators that were considered by the researchers in physical properties were frequency and density, 34.21% and 34.21% of the studies respectively.
Dust detection methods show that the use of thermal or reflective bands cannot detect dust phenomena with high precision, therefore, a model which applies both bands simultaneously should be developed. In other words, applying a combination of reflective and thermal
spectra of Military Origin Destination Information System (MODIS) could offer better
results in detection of dust storms in the study area. Studies indicate that most of the storms
originate outside of Iran. Moreover, exposure to airborne contaminants, especially when the
dust storms occur in the Middle East, can lead to an increase in the related disease outbreak
in the study area. For instance, there was a 70% increase in referring to medical centers for
lung related problems when a dust phenomenon occurred.
The Results showed that in cold seasons where low height and western waves is formed on the European and Mediterranean Sea, due to the heaviness, cold air in these days, can penetrate low latitudes and their trough is located over the Middle East area. Under warming condition, the front of rough is formed as ridge, then engendered turbulence and wind. In the warm seasons, thermal low pressure is rapt to ward in the high latitude, and severe dryness
of the area is also due to the fact that the dusty phenomenon is intensified in the area. Dust
storm occurrence in the summer due to bareness of the land, transparency of the atmosphere,
dryness of the air and the vast plains, which can reduce the formation of local instability in
the case of a sharp rise in air temperature. The dispersal of deserts and sand sea is mainly in
the northwest of Khuzestan province, especially in Fakkeh and Moussan which are located in the western borders of Iran with Iraq, which cover most of the Azadegan plain and west of the Karkheh and Mollasani and Maroon Rivers, and ultimately end in the Omidiyeh and Aghajari regions. Results show that the border between Syria and northwest Iraq, west and southwest of Iraq to east and northeast of Saudi Arabia are the main sources of dust in the studied region
. Synoptic conditions considering simultaneously with the occurrence of dust
storms showed the significant role of cyclonic systems in the occurrence and transfer of this
phenomenon. With the phenomenon occurrence during the warm period, the significant
strengthening in low pressure of Iraq along with the trough formation in Zagros causes the
formation and transfer of dust towards Southwest Iran. Simulation studies of dust particles
movement paths have shown that most of the paths are from the northern and central parts
of Iraq and Syria and the source of dust storms are deserts and dry regions of the northern
and central parts of Iraq and Syria. In addition, the study of the transmission paths of particles
in dust storms indicates the presence of a lower level jet, which causes horizontal
displacement of dust particles in a shallow layer and prevents its vertical propagation in the
higher layers of the atmosphere. In general, although the dust phenomenon is transnational
and uncontrollable, it can introduce limitations in terms of circulation patterns and statistical
properties at different time intervals to the different planners via its time and scope which
will necessitate appropriate programs for combating and adaptation.
Keywords: Dust, Air pollution, Spatio-temporal pattern, Southwest, Iran.
Dust storms are natural hazards that mostly occur in arid and semi-arid regions and there are many harmful consequences. According to the topographic-climatic conditions in Iran and the significant increase in the number and severity of dust storms occurrence in recent decades, especially in the West and Southwest regions where the dust storms are the most important environmental crisis. Studying this phenomenon is necessary for better management its harmful effects.
Since most of the research are implemented as different case studies, and there is no comprehensive study that review a wide range of existing researches with overall results in the southwestern parts of Iran, in this study a comprehensive overview of available literature reviews are addressed including dust spatio-temporal variations, modeling, detection, and health issues.
This research is based on a library research and search of valid national and international scientific articles about the dust crisis and no data-processing. We attempted to analyze temporal and spatial variations in the south and southwest of the country using the available studies and the challenges of this phenomenon in the past and present to provide a new perspective to apply a comprehensive land management and managing environmental hazards in Iran with all the problems.
A review of the history of dust storm studies from information sources showed that most researchers (61.40%) used a synoptic method to study dust storms, and the most important indicators that were considered by the researchers in physical properties were frequency and density, 34.21% and 34.21% of the studies respectively.
Dust detection methods show that the use of thermal or reflective bands cannot detect dust phenomena with high precision, therefore, a model which applies both bands simultaneously should be developed. In other words, applying a combination of reflective and thermal
spectra of Military Origin Destination Information System (MODIS) could offer better
results in detection of dust storms in the study area. Studies indicate that most of the storms
originate outside of Iran. Moreover, exposure to airborne contaminants, especially when the
dust storms occur in the Middle East, can lead to an increase in the related disease outbreak
in the study area. For instance, there was a 70% increase in referring to medical centers for
lung related problems when a dust phenomenon occurred.
The Results showed that in cold seasons where low height and western waves is formed on the European and Mediterranean Sea, due to the heaviness, cold air in these days, can penetrate low latitudes and their trough is located over the Middle East area. Under warming condition, the front of rough is formed as ridge, then engendered turbulence and wind. In the warm seasons, thermal low pressure is rapt to ward in the high latitude, and severe dryness
of the area is also due to the fact that the dusty phenomenon is intensified in the area. Dust
storm occurrence in the summer due to bareness of the land, transparency of the atmosphere,
dryness of the air and the vast plains, which can reduce the formation of local instability in
the case of a sharp rise in air temperature. The dispersal of deserts and sand sea is mainly in
the northwest of Khuzestan province, especially in Fakkeh and Moussan which are located in the western borders of Iran with Iraq, which cover most of the Azadegan plain and west of the Karkheh and Mollasani and Maroon Rivers, and ultimately end in the Omidiyeh and Aghajari regions. Results show that the border between Syria and northwest Iraq, west and southwest of Iraq to east and northeast of Saudi Arabia are the main sources of dust in the studied region
. Synoptic conditions considering simultaneously with the occurrence of dust
storms showed the significant role of cyclonic systems in the occurrence and transfer of this
phenomenon. With the phenomenon occurrence during the warm period, the significant
strengthening in low pressure of Iraq along with the trough formation in Zagros causes the
formation and transfer of dust towards Southwest Iran. Simulation studies of dust particles
movement paths have shown that most of the paths are from the northern and central parts
of Iraq and Syria and the source of dust storms are deserts and dry regions of the northern
and central parts of Iraq and Syria. In addition, the study of the transmission paths of particles
in dust storms indicates the presence of a lower level jet, which causes horizontal
displacement of dust particles in a shallow layer and prevents its vertical propagation in the
higher layers of the atmosphere. In general, although the dust phenomenon is transnational
and uncontrollable, it can introduce limitations in terms of circulation patterns and statistical
properties at different time intervals to the different planners via its time and scope which
will necessitate appropriate programs for combating and adaptation.
Keywords: Dust, Air pollution, Spatio-temporal pattern, Southwest, Iran.
Dr Mohammad Ghasem Torkashvand,
Volume 5, Issue 2 (9-2018)
Volume 5, Issue 2 (9-2018)
Abstract
Dust phenomenon is a natural occurrence that occurs widespread in arid and semi-arid regions of the world, especially in the sub-equatorial latitudes. This phenomenon is among the greatest environmental problems in the world. The release of this destructive climatic phenomenon in a scattered manner in the atmosphere varies in size, time and concentration. Since this phenomenon is influenced by the specific conditions of climate effects, its effects may continue to be as close as 16,000 kilometers from the source and cause abnormal environmental effects on the one hand, and numerous damage to agriculture, industry, transportation and telecommunication systems on the other hand. Dust storms, as an atmospheric destructive phenomenon, have created adverse environmental impacts for the west of Iran and caused many problems for the inhabitants of this region. Therefore, studying this phenomenon is necessary in order to achieve a comprehensive approach to deal with it. The present study was conducted with the aim of identifying the instantaneous atmospheric conditions, conduction and source of the dust storms with a synoptic modeling approach.
In this study, in order to investigate the dust storms structure in the southwest of Iran, the dust storm occurred on May 15, 2015 was selected. The reason for choosing the present day, based on reports from the Observatory and Monitoring Center of Ilam’s Environmental Protection Office, was the most polluted day of 2015, so the amount of aerosol recorded was 1200 µg/m3 in the air of Mehran City. To analyze the storm structure, a combination study was performed using NECP/NCAR reanalyzed digital data and output of dynamic and regional models. The first group consisted of three regional models of NAAPS, DREAM 8b and NMMB/BSC, and the second group included HYSPLIT dynamic model with backward method. NECP / NCAR data are also used in the synoptic analysis of the storm.
The average slope of air pressure in the sea level at the time of the dust storm in the west of Iran has increased and a high pressure difference of 20 hPa is observed between east and west of Iran, which is accompanied by a high pressure difference and severe winds in the southwestern borders of Iran. Also, the surface moisture flux of the soil has fallen sharply for the day of the storm occurrence in the study area. High advection in the Western part of Iran has been accompanied by a change in the density and mass of the air with heat, resulting in very rapid and intense air rotational movements around the Earth's surface; on the other hand, the coincidence of the positive and negative vorticity in a single significant amount in the formation of the lower level jet has caused the emergence of the dust storm to occur in the mentioned day. On the day of the dust storm, the orbital component of the wind speed was Western, and its velocity was more than 5 meters per second on the western borders of the country. The meridian component of the wind speed was also Southern. Therefore, the effect of present pattern on west of Iran during the day of storm dust has played a significant role. The optical depth index and surface dust concentration index in the NAAPS model have shown that dust concentrations ranged from 640 to 1260 µg/m3 to the west. Besides, the amount of sulfate in the region was estimated to be between 1 and 2 µg/m3. Comparison of the output of DREAM Bb and NMMB / BSC models showed an increase in concentration values per Dust surface unit on the day of storm occurrence. Based on the results of two models of DREAM Bb and NMMB / BSC in the case of western dust in Iran, it can be concluded that the effect of local factors and close proximity to the centers of the dust source have a significant role in the occurrence of present phenomena for western Iran. The simulation of the Dust storm direction with the HYSPLIT dynamic model and the backward method has shown two routes of dust entering the west of the country; a) Northwest - Southeast; b) West-East direction. The main origins of the first route, the northwest of Iraq and the east of Syria, and the second route were the center of Iraq.
Keywords: Spring dust storms, Regional modeling, HYSPLIT model, particles optical depth, West Iran
Mr Vahid Safarian Zengir, Dr Batol Zenali, Mr Yusuf Jafari Hasi Kennedy, Miss Leyla Jafarzadeh,
Volume 5, Issue 2 (9-2018)
Volume 5, Issue 2 (9-2018)
Abstract
Investigation and evaluation of dust and microstrip phenomena is one of the important values in the management of climate and environmental hazards in the Middle East, especially in the arid, western, southern and central parts of Iran. Methods and plans for studying this phenomenon and its management are of great importance and great value. According to studies on dust phenomena based on predictive methods with low error, contradictory and low, the evaluation of the characteristics of dust and its prediction will reduce the irreparable damage that results from it. To do this, in this research, dust monitoring and assessment of its prediction in Ardebil province was performed using the ANFIS model. The data used in this study is the amount of dust in the relevant statistical period to each station from its inception until 2016. The dust phenomenon was used in the observed and predicted time intervals to assess the dust and the ANFIS model for predicting dust phenomena. According to the findings of this study, in the monitoring and prediction of dust situation, the frequency of occurrence in observed years in the maximum amount of dust in Ardabil station with 74% and the lowest in Mashgin is 8%. In the years to come, the maximum amount of dust at Khalkhal Station was 61.67% and the lowest was 10% in Mashgin. In terms of amount of dust, the Ardebil station is more intense than the rest of the stations. In terms of the severity of drought that has been studied, each of the 5 stations studied has a dust concentration of more than 74%. For the 5 stations studied for the next 18 years using manually generated codes, the stations were divided in time series, with the highest average error of training at Pars-Abad Moghan Station with 0.091% and less The highest value was obtained at the Grammy station with a value of 0.001%.
Mr Dana Rostami, Dr Seyed Asaad Hosseini,
Volume 5, Issue 3 (12-2018)
Volume 5, Issue 3 (12-2018)
Abstract
Dust is one of the environmental hazards and atmospheric phenomena familiar to residents of the southern and southeastern parts of the country. Which each year causes a lot of damages to various sectors such as environment, agriculture, health, transportation, facilities, and so on. Therefore, in this research, we investigated and identified the sources of dust in the area, the intensity and frequency of dust, its governing patterns and dust-free areas during the 30-year statistical period (1984-1984). The research method is a combination of statistical, synoptic and remote sensing analysis. The data used include the hourly data of 22 synoptic stations (8 times per 24 hours), CDC1 data up to 2006, and then GDAS data, temperature, wind direction and wind speed, geopotential height at different levels. In selecting the studied days, it was tried to select the selected samples with a duration of three days and more, the spatial expansion of at least 4 stations with horizontal vision less than 1000 meters. For this purpose, were used the characteristics of the 11.3 and 12-micrometric wavelengths of the wavelengths were used to visualize the dust on the MODIS images from the ENVI 5.2 software environment, to track the wind direction from the GDAS data in the HYSPLIT software environment and to study the maps of various atmospheric levels from Temperature, wind speed, wind speed and geopotential heights were used from GRADS software and weather data stations. The annual frequency of the occurrence of days with dusty phenomena in the study area showed that during the statistical period of 1984-2013, a total of 11616 days with dust was recorded with the 06 code for south and southeast of Iran at the stations study. Most days with the dust event at Zabol Station with 1136 days and the lowest occurrence occurred at Bandar Abbas Station with 171 days during the studied period. In general, the annual survey of the data shows that the phenomenon of dust in the stations study in the past has been high and very high; however, in recent years, it has been expanding more and more than the past, and has been growing. The results of the monthly and seasonal surveys showed that the summer and the months of June, July, August and May are the most frequent and most frequent, with a peak of 1000 meters, respectively, and December have the lowest dust incidence and Zabul and Zahedan station
Zahra Hejazizadeh, Meysam Toulabi Nejad, Zahra Zarei Chaghabalaki, Behzad Amraeei,
Volume 5, Issue 4 (3-2019)
Volume 5, Issue 4 (3-2019)
Abstract
This research was conducted to identify the dust storms in the Midwest of Iran from June 16 to 19, 2015. To investigate the synoptic conditions of the causes of this phenomenon, the ECMWF has an array of 0.125 degrees, including geopotential, omega, and sea level pressure, orbital and meridian components of the wind, specific humidity Soil moisture was applied to a depth of 10 cm. Similarly, for the purpose of routing the source of dust particles, the model of the Minimum Meteorological Parameters (HYSPLIT) Marv was used. The results of this study showed that in Lorestan province, non-ditches created by low-pressure thermal springs and high-altitude movements in Saudi Arabia caused the convergence and sucking of flows to the west of the country, as well as the establishment of a low-pressure cut at the middle levels of the atmosphere in the east of the Caspian. In the event of this risk, it has been effective. According to the average soil moisture from the surface of the earth to a depth of 10 cm in days with dust hazards, the moisture content of dust particles in the dust was less than 15%, due to the flow of streams from these fields without sufficient moisture, fine particles the soil is easily directed towards the study. A survey of Hysplit tracking maps shows that two general paths for the transfer of dust to the studied region can be detected. 1-Northwest - Southwest At an altitude of 1500 meters: passing through the dust nuclei formed in the northwest of Iraq and east of Syria, carry out the transfer of dust to the west-west of Iran. As these currents have been able to transfer dust to the southwest of Iran, this path can be considered the main route of dust dispersion to the region. 2- The western-eastern route at an altitude of 500 to 1000 meters: is the source of particles of this route inside the country (around Hurralazim) that entered the West of Iran and greatly reduced the horizontal visibility, which is the main source of dust on June 18 and 19. The investigation of the path of dust particles in the walnut shows that these particles were initially transferred to lower levels by low-pressure systems in the Midwest of Iran and then pulled in three directions on the ground.
Mohammad Hajipour, Vahid Riahi, Golsar Hajipour,
Volume 6, Issue 1 (5-2019)
Volume 6, Issue 1 (5-2019)
Abstract
Introduction
There are two questions with all programs and efforts to industry development in Iran: I) How much is rate of environmental hazard of industries in each Iran regions? II) How much is rate of capital production of industrial sector to environmental damages in regions of Iran?
Explanation and Interpretation of the Results
In recent years (2009-13), despite a reduction in the number of industrial workshops in the country as a whole, pollution and ecological damage to industries had more than doubled in the past; On the other hand, industries has been more conflict with the environment increasingly in Iran and has led to the growth of human environment hazards with increase of damage to natural environment. Also, from a regional point of view, wherever more industry is not more damage to environment by industry necessarily. Factors such as “obsolete instruments in industry”, “low level of technology”, “insufficient skills and expertise of the activists in industry” and “Inattention of managers and industrialists to environmental health” has been causes damage growing to environment. Space pattern suggests industrial sector risks accumulated within South West of Iran. As well as according to spatial changes trend, the risks are drawn towards central regions of the country. Among the provinces, Markazi province has been damage most to environment than any one million riyals added value of industry sector activities. As well as provinces such as Mazandaran, Bushehr, Fars, Isfahan, Ardebil and West Azarbaijan has been next ranks. Finally, it can be concluded that the environment health is not important for capital production from industrial sector of in the regions.
Dr Abbas Ali Vali, Dr Sayyed Hojjat Mousavi, Mr Esmaeil Zamani,
Volume 6, Issue 3 (9-2019)
Volume 6, Issue 3 (9-2019)
Abstract
Introduction
Dust storms as one of the environmental hazards of the arid regions of the globe, including the southern, southwestern, eastern and central parts of Iran, has caused many environmental problems that confirm the need for studying and crisis managing its in scientific and executive congresses. Therefore, the present study attempts to evaluate the effects of climate elements on temperature, precipitation, humidity, evapotranspiration and vegetation index on the frequency of dust storms in Yazd province during the period of 5 years (2009-2014).
Data and Methodology
So, after determining the synoptic stations of the area, the dust data were extracted based on the code of the present weather phenomena and the values of the climatic elements. In the next step, their spatial zonation was determined through the interpolation method. Then, using the MODIS images, EVI index data were calculated according to the principle of time matching. Finally, a variety of simple and multiple regression models were fitted to estimate the occurrence frequency of dust, and the most appropriate relationships with higher preference values were reported.
Findings and Conclusions
The results showed that there was a significant relationship between the total dust with evapotranspiration and relative humidity with a R square of 0.973 and 0.614 and the standard deviation of 24.104 and 92.477 at sig. level of 99% and 95%. Also, there is the maximum significant relation between external dust with evapotranspiration and relative humidity with a R square 0.968 and 0.621, and the standard deviation was estimated to be 0.173 and 75.427 at sig. level of 99% and 95%, respectively. Internal dusts with evapotranspiration and maximum temperature with a R square of 0.770 and 0.377 and standard deviation of 15.1751 and 64.22 have a significant relationship with sig. level of 95%. The results of the total, external and internal dust storms with climatic elements and vegetation cover showed a significant correlation with the R square of 0.994, 0.988 and 0.956 and the standard error of estimation of 18.13713, 24.2555551 and 10.49989 at sig. level of 99% and 95%, respectively, which indicates the systematic function of climatic elements and vegetation cover in the occurrence of dust.
Dr Bromand Salahi, Dr Mahomud Behrozi,
Volume 7, Issue 1 (5-2020)
Volume 7, Issue 1 (5-2020)
Abstract
Investigating the effect of desert micro-organisms on vegetative traits and yield of grapevine in Shiraz
Extended Abstract
Introduction
Mineral aerosols as a pollution of atmosphere has become a global concern with environmental impacts on human, Vegetable and transportation system. Plants exposed to aerosol exhibit morphological and physiological changes. Dust particles is one of the aerosols in the atmosphere which deposits on the leaf of plants can alter their available light of photosynthesis. This interferes with gas exchange of CO2 between the leaf and air of environment, and the reduction of leaf stomatal conductance. Finally reduction the yield of plants. Grapevines Vitis vinifera. Askari, are grown extensively in the Shiraz city. The period from March to July coincides with extensive shoot and fruit which these processes depend on environment conditions. Any stress reducing fruit set and leaf characterizes, will negatively affect grapevine productivity. Thus, the objective of this study was to examine the effects of dust deposits on grapevine leaves and to estimate the impact on vegetative traits and yield of grapevine.
Method
Experiments were implemented on 36 grapevines V.vinifera L. cv. Askari in the form of RCBD with drip irrigation during 2017-2018 from late March to July when the buds grow until the harvest. Treatments included: T1) artificial dust sprayed on canopy of vine by a manually operated duster, T2) washing canopy of vines using well water in the field after spraying artificial dust, and T3) control. Artificial dust particles were collected from uncultivated areas of Azadegan plain in Khuzestan province. To provide suitable fine particles, the soil was grinded, milled and sieved using a mesh size of 200 opening per inches. The physical and chemical tests were performed using an X-ray diffraction device. A dust chamber and a dust generator were constructed to simulate dust. A mechanical apparatus consisted of a 50-cm pipe and a ventilation fan was also used. The chamber was made of a plastic sheet with 2×2×1.5 m dimensions. To evaluate chlorophylls a and b concentration, used by spectrophotometer in wavelengths of 647 nm and 663 nm. Single Leaf Area Index (LAI) was calculated by image processing method Win-Area-Ut_10 system. The sugar content of grapes was determined by measuring the Refrectometer BME center index of their juice sugar. Also measured the RWC, fruit set percentage, Length of Branch Leaf Dry Weight and Yield.
Results
The mean of particle size was 10.6 μm and the chemical composition of these particles included Silicon Oxide, Sodium Sulfate, Na = 6.14 mg/L, K = 10.73 mg/L, Ca = 23.9 meq/L and Mg = 3.5 meq/L. Chlorophyll a and b content decreased by dust particles treatment in the throughout the phonological stages of grapevine and had a significantly different as compared to washing and control treatments. RWC was reduced in the dust treatment as compared to the washing and control treatment (P < 0.05). The maximum of Leaf Area Index (131 cm2) was obtained in the control and the minimum (86 cm2) was obtained in the dust treatment. The maximum percentage of fruit set was obtained in the washing treatment (24%). but, the lowest fruit set trait (18%) was found in the dust treatment. The highest TSS (22.7 %) was observed in the washing treatment and the lowest TSS (18.1%) was seen in the dust treatment. The difference among the numbers of berries among treatments was significant (P < 0.05). The highest and the lowest numbers of berries were observed in the washing treatment (87 berries per bunch) and the dust treatment (49 berries per bunch). The heaviest bunch was observed in the washing treatment (158.7 g), while the lightest bunch weight (100 g) was observed in the dust treatment which had significantly difference with control and washing treatments. The highest yield (22.5 kg/vine) was observed in the washing treatment and the lowest yield (7.9 kg/vine) was observed in the dust treatment, whereas control produced 19.5 kg/vine averagely.
Conclusion
It was found that dust accumulation on the surface of leaf grapevine Askari induces some physiological changes such as a reduction of photosynthetic pigments, relative water content and leaf area. Deposition of dust particles on flower of grape led to decrease of reproductive trait, but washing vine by water led to improvement of production. As a result, washing of vine also increased grape production as compared to the control treatment. According to the results, dust particles reduced fruit set by deposition on flower and they were identified as an environmental stress on grapevine. More importantly, the results revealed that yield of grapevine was adversely affected by dust deposits over a short interval of time during the fruit set. Therefore, the fruit set stage, in which the fruit is formed, was recognized as the most important stage in plant production. It was also found that removal of dust particles from the plant leaves by washing methods can reduce the effects of dust particles.
Keywords: Dust, Chlorophyll, Fruit, Sugar, Shiraz.
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.
Nader Shohani, Farshad Shohani, Fariba Shohani, Hakim Bakrizadeh, Shamsollah Asgari,
Volume 7, Issue 4 (2-2021)
Volume 7, Issue 4 (2-2021)
Abstract
Abstract
Iran and especially the West and Southwest regions of Iran are intermittently confronted with the phenomenon of dust and its problems. West of Iran Due to the natural environment and proximity to areas of dust source in West Asia, a region susceptible to the occurrence of dust phenomena is frequent. Fragments are the most important and perhaps the main threat to the health of individuals. Statistics show the destructive and negative effects of these microorganisms or The same dust is on people in the West and Southwest of Iran. Statistics and studies from the south and west of the country show that more than 100 days have been infected between the years 77 to 91, which has many health problems, and others Items have been created.Method of research In this article, a descriptive-analytical study. Then, using a questionnaire on the relationship between the phenomenon of dust and the health of citizens with the hypothesis: there is a significant relationship between the phenomenon of dust and the occurrence or exacerbation of heart disease in residents of Ilam. This study is a descriptive-analytic study in terms of post-event topic. The statistical population of this study was all patients admitted to Mustafa Khomeini Hospital in Ilam in the years 92-88.
In this paper, we try to first analyze the dust phenomenon, the frequency of its occurrence in the past and recent decades, and investigate the origin and conditions of formation of the phenomenon, and then to the effect Dusty storms on the cardiovascular health of the inhabitants of the area (with an emphasis on the city of Ilam). The results of multivariate statistical analysis including Pearson correlation coefficient, regression test, Chi-square test, ANOVA (variance analysis), and Kundal's correlation test showed that the relationship between the arrival of microorganisms in the statistical period of the study with the number of patients suffering from cardiovascular disease At the significance level, 0.05 was significant and indicates the existence of the relationship. This means that as the amount of entropy to the city of Ilam increased, the number of cases of this disease also increased.
Iran and especially the West and Southwest regions of Iran are intermittently confronted with the phenomenon of dust and its problems. West of Iran Due to the natural environment and proximity to areas of dust source in West Asia, a region susceptible to the occurrence of dust phenomena is frequent. Fragments are the most important and perhaps the main threat to the health of individuals. Statistics show the destructive and negative effects of these microorganisms or The same dust is on people in the West and Southwest of Iran. Statistics and studies from the south and west of the country show that more than 100 days have been infected between the years 77 to 91, which has many health problems, and others Items have been created.Method of research In this article, a descriptive-analytical study. Then, using a questionnaire on the relationship between the phenomenon of dust and the health of citizens with the hypothesis: there is a significant relationship between the phenomenon of dust and the occurrence or exacerbation of heart disease in residents of Ilam. This study is a descriptive-analytic study in terms of post-event topic. The statistical population of this study was all patients admitted to Mustafa Khomeini Hospital in Ilam in the years 92-88.
In this paper, we try to first analyze the dust phenomenon, the frequency of its occurrence in the past and recent decades, and investigate the origin and conditions of formation of the phenomenon, and then to the effect Dusty storms on the cardiovascular health of the inhabitants of the area (with an emphasis on the city of Ilam). The results of multivariate statistical analysis including Pearson correlation coefficient, regression test, Chi-square test, ANOVA (variance analysis), and Kundal's correlation test showed that the relationship between the arrival of microorganisms in the statistical period of the study with the number of patients suffering from cardiovascular disease At the significance level, 0.05 was significant and indicates the existence of the relationship. This means that as the amount of entropy to the city of Ilam increased, the number of cases of this disease also increased.
Mr Hossien Rahi Zehi, Dr Mahmood Khosravi, Dr Mohsen Hamidian Pour,
Volume 8, Issue 1 (5-2021)
Volume 8, Issue 1 (5-2021)
Abstract
The Spatio-Temporal Variations of Aerosol Concentration Using Remote Sensing in Sistan and Baluchestan Province (2018 - 2000)
Abstract
Atmospheric particles play an important role in balancing the energy budget of the Earth's surface. The Sistan and Baluchestan province because of the specific geographical conditions during the year is witnessing the spread of dust particles caused by dust storms. This paper investigates the spatial changes of this phenomenon in the region to identify the association of dust accumulation and the reasons for these concentrations. In this study, the AOD Index data of the Aqua and Terra Modis Satellite Sensor (MODAL2_M_AER_OD) with 10 × 10 km spatial resolution were used. Then, by using statistical methods, a spatial analysis was done and the temporal and spatial changes trends at 95% and 99% significance level were performed using the nonparametric Mann-Kendall method. The results showed that the maximum concentration of aerosol in areas such as Zabol, Zahak, Hirmand, Hamoun, Iranshahr, Bampour, Jazmurian basin, Chabahar, and Konarak. On average, the highest variations in aerosol concentration were in the southern regions of the province include Dashtiari, Polan, and Chabahar, and the least in the northern part of Polan, Chabahar, Konark, and Bampour areas. The trend of changes was evaluated at two significant levels of 95 and 99%. The results of this section showed that the AOD had a positive and increasing trend in June, July, and August in the areas of Dalgan, Iranshahr, Bampour, Bazman, Mirjaveh, Nokabad, Zahedan, Nosratabad, Zaboli, Qasrqand, Irandegan, and Sib-va-Soran Plain and areas such as Korin, Zabol, Zahak, Sirkan (Bamposht), Hamoun have a negative and decreasing trend. The average changes in aerosol concentration in June, July, and August show a significant increase in the aerosol concentration from 2015 to 2018 up to 0.8.
Keywords: Environmental Changes, Dust, Environmental Hazards, Climate.
Fatemeh Dargahian, Mohammad Khosroshahi, Sakineh Lotfinasabasl,
Volume 8, Issue 2 (9-2021)
Volume 8, Issue 2 (9-2021)
Abstract
Potential dangers of drought in Shadegan wetland and Identify areas affected by dust from it
Introduction
Shadegan wetland is located at the end of Jarahi watershed. This wetland is one of the most important international wetlands registered in the Ramsar Convention, which is currently undergoing ecological changes and is still on the red list of the Montero Ramsar list. This wetland is extremely important due to its high biodiversity and various functions such as flood control, air conditioning and soil erosion control, habitat of various plants and animals and providing livelihood for a part of human societies. One of the most important functions of the wetland, according to the findings of the present study, is the important role of Shadegan wetland in preventing the production and control of fine dust. There are 143 wetlands in Iran, of which 25 are registered in the Ramsar Convention. Shadegan wetland is one of the wetlands of Ramsar Convention, which in the last decade, a large area of it has become dry and has become a center of dust. In this research, it is important to know that in case of drying of Shadegan wetland, which areas in which seasons will be more affected by dust due to atmospheric currents.
Data and methodology
In this study, the boundary of the wetland was determined based on the highest water advance line during a 30-year statistical period (1988-2017). According to satellite images, the border of the wetland has been determined to be about 164,000 hectares based on the rainiest year and month. Wetland area changes were used to monitor the water level of Shadegan Wetland through Landsat TM, ETM + and OLI satellite data from 1998 to 2017 in the period of June. Three stages of preprocessing, processing and post-processing were performed on the images and supervised classification by support vector machine (SVM) method was used and the images were classified into three classes of water, vegetation and without cover or soil. On the other hand, the classification accuracy for the images was calculated using two indicators, overall accuracy and kappa. To calculate the dry area of the lagoon, floor changes without cover were calculated. The most important cities around Shadegan wetland, which in case of wetland drought may be most affected by wetland dust due to proximity and proximity, and have socio-economic importance and the center of the province and port status, were identified. In this study, the cities of Ahvaz, Abadan and Mahshahr were identified and studied as areas affected by wetland dust during drought. In order to study the role of drying of Shadegan wetland in the dust of the surrounding areas, seasonal and annual dust mites were prepared and drawn. Data on the direction and speed of hourly winds along with the dust were used. Then, using WR-PLOT software, in addition to the annual long-term total rainfall, the seasonal distribution of the direction and speed of events was extracted and the rainfall related to each season was plotted and analyzed, and areas affected by drought in different seasons of the year. Wetlands with greater impact were identified.
Result
The trend of 30-year changes in the soil cover of Shadegan wetland is increasing in total, so that according to the freshwater area of the wetland, which was obtained in this study 164 thousand hectares, 22960 square kilometers has been added to the dry area of the wetland during these 30 years. The largest soil area of the wetland in 1994 was about 87.4% of the total area of the wetland. The lowest soil area of the wetland in 1998 was about 19%. Sugarcane projects have entered the wetland from the north of Shadegan Zahab Wetland since 2002, but due to widespread drought, it has not been able to increase vegetation and reduce the soil area of the wetland.
During the long-term statistical period, spring is the predominant period of pollination in Ahvaz western synoptic station and secondarily in the northwest. The southeast direction is of third importance, but nevertheless, the dryness of the north and northeast parts of the wetland can affect the south and southeast of Ahvaz in this season in Abadan synoptic station. Drought on the west side of the wetland is not a threat to the city of Abadan. In Mahshahr synoptic station, the predominant direction of long-term seasonal rainfall is northwest. In case of drought, Shadegan wetland will be affected from the northwest. During the long-term statistical period, the summer season was dominated by dust and affected in three stations, such as the spring season, with the difference that in this season, dust is more abundant. During the long-term statistical period, autumn is the predominant direction for flowering and is affected in three stations such as spring and summer, but in this season, the southeast and south directions are more intense and frequent than spring and summer.
During the long-term statistical period, winter is the predominant period of pollination in Ahvaz synoptic station, west and secondarily, northwest. The southeast and south directions are of third importance, but in this season, the southeast and south directions are more intense and frequent than other seasons. In this season, due to the expansion of the westerly wind to the lower offerings, unstable atmospheric systems enter Khuzestan from the south and southeast and bring dust with them from areas such as western and southern Iraq and northern Saudi Arabia, and to the southeast. Northwest and passing through the dry parts of the lagoon and the active dust center of the southeast of Ahvaz, the metropolis of Ahvaz will face problems caused by dust in this season. Due to the cold weather and the inversion phenomenon, the dust of this season, which is associated with wetland and inland resources, has a greater impact on the field of view and causes great damage to the equipment and infrastructure facilities by subsiding on the city of Ahvaz.
Conclusion
Drying of wetlands due to various climatic or human factors can lead to increased dust activities. When a wetland dries out, the salts that settle in it become sources of dust. Wetland fine-grained sediments with air velocity less than the erosion threshold due to small diameter and large volume enter the air streams and are dispersed in the air. Active dust centers in the southern half of Khuzestan province have the largest area in the whole country. Shadegan wetland is bounded on the north by the dust center of the south and southeast of Ahvaz with an area of 185043.3 hectares and on the west by the center of the south of Horalazim and north of Khorramshahr with an area of 258916.4 hectares and on the east by the dust center of Mahshahr - Omidieh Hindijan with an area of 254654.4. Shadegan wetland joins the southeastern center of Ahvaz in case of drought from the north and northeast, as if parts of it, known as Hor Mansoureh, have become part of the southeastern center of Ahvaz in the last decade due to several droughts. Is. From the west, parts of it are connected to the dust center north of Khorramshahr and join it if the drought continues. It is connected to Mahshahr-Omidieh and Hindijan centers from the east. In recent years, parts of the wetland and dust centers have overlapped. If the wetland continues and dries, for natural and managerial reasons, more parts of the wetland will dry up and become dust centers and affect important population, political and port cities of Khuzestan Data and will face irreparable social and economic losses.
Keywords: Dust center, dust, wind direction and speed, Shadegan wetland, Right of water
Fatemeh Arsalani, Bohloul Alijani, Sabereh Arsalani,
Volume 8, Issue 4 (1-2021)
Volume 8, Issue 4 (1-2021)
Abstract
Dust fall means the dust that in the air fall down on the ground (Hai et al, 2008). it is important to study the extent of heavy metal contamination of dust fall due to their threats that could affect human health. Due to the fact that the metropolis of Tehran has a population of over eight million people and One of the major cities in the world is currently facing a severe air pollution problem. The purpose of the present study was to determine the level of pollution and health risk of heavy metals such as Cd, Cr, Cu, Ni, Pb in the dust falling of Tehran city. the Dust fallout samples were collected using Marble Dust Collector (MDCO) from 28 different locations across Tehran during the statistical period (2018/03/21- 2018/06/21). We used XRF analysis To identify and determine the concentration of heavy metals (Cd,Cr,Cu,Ni,Pb,Fe) in the collected dust. we used to spatial analysis to determine Dispersion of pollution levels and health risk in different Zone of Tehran city. In order to determine the level of pollution and Health Risk Assessment we used the pollution index (PI), integrated pollution index (IPI), Non-Carcinogenic Risk and Carcinogenic Risk. Based on the results of the calculations performed in the statistical period studied, the values of pollution index (PI) and integrated pollution index (IPI) are Pb> Cd> Cu> Cr> Ni, respectively. Accordingly, the regional trend of pollution from west to east is increasing. Therefore, Tehran's pollution index is high level of pollution in the most zone and and extremely high level of pollution in the eastern zone, which is a more worrying situation. Probably one of the reasons is the western winds, which are faster in the west than in the east. Also, Tehran's topographic pattern plays a role in this issue. Health risk assessment (HQ, HI, CR) showed that the contamination of the heavy elements studied was lower than the acceptable threshold for carcinogenic and non-carcinogenic risks. Therefore, it is not dangerous in terms of carcinogenicity. The risk of carcinogenicity and non-carcinogenicity in children and adults is higher in the southern and eastern zone of Tehran. Probably one of the reasons is the establishment of metal industries, cement production, sand mines and combustion processes in the south and west of Tehran metropolis.
Understanding the mechanism of the atmospheric anomalies governing the summer dust in northeast Iran
Ms. Tahmineh Chehreara, Miss Somayeh Hajivand Paydari,
Volume 8, Issue 4 (1-2021)
Volume 8, Issue 4 (1-2021)
Abstract
Identification of dust centers and, of course, the behavior of this phenomenon in different regions creates one of the problems of the last few decades, which is investigated as a hazard. To this end, statistics from 15 meteorological stations in the northeastern region of Iran, including North Khorasan, Razavi Khorasan, and South Khorasan provinces, were used over a 17-year period (2016-2000). To clarify the mechanisms governing dusty days, the meridional and zonal wind components and geopotential height were obtained by referring to the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). HYSPLIT model and MODIS AOD values were used to track and identify dust centers. The results showed that during the warm season, due to the establishment of a strong quasi-stationary blocking system in the lower levels of the atmosphere, negative vorticity increased in the maximum air descent area, ultimately leading to the dominance of a northern flow for the region. Anomalies in geopotential height and vorticity were identified, and three dominant abnormal patterns were found in the occurrence of maximum dust storms in the region. An increase in geopotential height of more than 5 to 10 geopotential meters and an increase in negative vorticity are considered major conditions. By examining the tracking model and using satellite data, five main centers that affect over 90% of the region's dust storms were identified, among which Turkmenistan has a significant role with two separate centers and one common center with Uzbekistan in the occurrence of summer dust storms in northeastern Iran.
Dr Hassan Lashkari, Dr Zainab Mohammadi,
Volume 9, Issue 1 (5-2022)
Volume 9, Issue 1 (5-2022)
Abstract
Synoptic analysis of the changes trend of the share of systems due to the Sudan low
In the cold period of the Persian Gulf coast during 1976-2017
Introduction
In the Ethiopian-Sudan range forms the low pressure system without front in the cold and transition seasons that is affecting the climate of the adjacent regions by crossing the Red sea. Based on the evidence in the context of Iran, studying Sudan low was first begun by Olfat in 1968. Olfat refers to low pressures which are formed in northeastern Africa and the Red Sea and then pass Saudi Arabia and the Persian Gulf, enter Iran, and finally, cause rainfall. The most comprehensive research specifically examining Sudan low, was the work carried out by the Lashkari in 1996. While he studying the floods that occurred in southwestern of Iran, he was identified Sudan low by the most important cause of such flooding and he explained how they are formed, and how these low-pressure systems were deployed on the southwest of Iran.
Materials and methods
The study period with long-term variations was considered from 9.5 to 11 years based on solar cycles. Precipitation data for 13 synoptic stations are considered above 5 mm in south and southwestern Iran. With three criteria were determined for the days of rainfall caused by each type of atmospheric system. The visual analysis of high and low altitude cores and geopotential height at 1000 hPa pressure level (El-Fandy, 1950a; Lashkari, 1996; 2002) were considered based on the aim of the study. Accordingly, the approximate locations of activity centers, as well as the range of the formation and displacement of the Sudan system were initially identified based on the location of the formation of low and high-pressure cores. Then, the rainy days due to the Sudan system in January were separated from the precipitation of the other atmospheric system.
Results and discussion
According to the selected criteria in the forty-year statistical period, 507 precipitation systems were identified with different continuities that led to precipitation in the northern coast of the Persian Gulf. The pattern of independent Sudan low rainfall was responsible for 77% of the precipitation in the Persian Gulf. Decade frequency share of Sudan low was lower in the first decade (16%) compared to the next three decades. This system of rainfall was more activated during the second and third decades compared to the first decade. However, rainfall changes were not evident in the mid-decade. Independent Sudan low precipitation provide 25% and 27% of the cold season precipitation of the Persian Gulf during the second and third decades respectively. In accordance with the 24th solar cycle, at the end of the study period, the Sudan low was more effective on the Gulf coast than ever before. During this decade, 125 cases of Sudan low rainfall was recorded for the Persian Gulf. Thus, the frequency of Sudan low during the fourth decade was about 31%, which was higher than in the rest of the decade. Overall, the Sudan low rainfall was repeated 151 times for 2 days rainfall, during the statistical period studied. This Precipitation has increased over the last decades compared to other periods.
Conclusion
The severe variability of rainfall along the timing and location of the permanent Persian Gulf coasts can have a significant impact on the economic and agricultural behavior of the Gulf population in the three provinces of Ahwaz, Bushehr and Hormozgan.The purpose of this study was to evaluate the precipitation changes due to Sudan low in the Persian Gulf coastal region during the cold period. The results of this study showed that the role of integration patterns in influencing the precipitation of the Persian Gulf coast has decreased with the strengthening and further activation of the Sudan low system during the last two decades. That way, about 77percent of the region's rainfall is provided by independent Sudan low. At the end of the course (in accordance with 24th solar cycle activity) the Sudan low system was more active than before. Although the Sudan low activity was different at each station during the period studied, but in the historical passage incremental and decade's positive behavior of Sudan low was common to all stations. Evaluation of changes in rainfall duration shows that the pattern of precipitation with 2days duration is more frequent than the patterns of one to several days.
Keywords: Sudan low- Solar cycle- Persian Gulf.
Fatemeh Dargahian, Mehdi Pourhashemi, Samaneh Razavizadeh,
Volume 9, Issue 2 (9-2022)
Volume 9, Issue 2 (9-2022)
Abstract
Evaluation of occurrence, tracing and origin of dust phenomenon in Zagros forest degradation monitoring sites of Chaharmahal and Bakhtiari province
Abstract
Decay and drought of oak has occurred in more than 40 countries, including Iran. Numerous factors have contributed to the drought and oak decay. Among the natural causes of climate change is common in all countries, but dust has played an important role as a contributing factor to the decline of the Zagros forests, which are adjacent to and the passage of dust currents. In this study, with the aim of investigating the occurrence of dust and its direction in Zagros deterioration monitoring sites in Chaharmahal and Bakhtiari province, meteorological statistics and data of the nearest synoptic station were used. Dust event codes were extracted from 100 phenomenon codes (0-99) and the frequency of dust events with different horizontal field of view was investigated. In order to identify the direction of dust entry, the graph diagram was used and to draw the dust, WR-PLOT software was used. Data related to wind direction and speed were extracted and wind direction and speed corresponding to dust days were extracted to enter the dust drawing software and converted to a special format of this software. HYSPLIT simulation model was used to identify the source of incoming dust sources in the area of deterioration monitoring sites. The results showed that the occurrence of dust in decay monitoring sites has an increasing trend and the path of dust entering the decay sites from the west and southwest and northwest have been important, respectively. And being in the path of incoming atmospheric currents has been affected by dust mites inside and outside the country. Tracing the origin of dust particles at three altitudes of 1000, 500 and 1500 meters showed that the most important sources of dust entering the region are from Iraq and Saudi Arabia, which has been strengthened by passing through the centers of domestic dust in Khuzestan province. Considering that the occurrence of dust and its entry path can be one of the factors contributing to the decline of Zagros oak trees and the extent of its effects is different in the south-north and west-east slopes, help decision makers and planners of forest ecosystems. At the macro level, with the control programs of domestic centers and international cooperation with neighboring countries to make fruitful and fruitful efforts to preserve and rehabilitate forests.
Keywords: Oak decay, Internal and External dust, Golghobar, WR-PLOT software, HYSPLIT model
Dr Ebrahim Yousefi Mobarhan, Dr Mansor Ghodrati, Dr Mohamad Khosroshahi,
Volume 9, Issue 4 (3-2023)
Volume 9, Issue 4 (3-2023)
Abstract
In the study of the trend of dust storm index, the results showed that the study period of 2003-2007 in Semnan province has an increasing trend and has shown significant changes in the 95% confidence range, but the lack of significant changes in the last decade shows the effects of various events. In cross-cutting decisions in the field of dust in the region. The zoning of the DSI index changes in different regions of the province in a 15-year statistical period indicates that from the west to the east of the province due to the increase in the frequency of stormy days with moderate dust (MDS), dust has increased. The correlation between drought and DSI index in Semnan province showed that although DSI index increased during the period under analysis with increasing drought intensity and its correlation with drought during the 15-year period was not significant, but the pattern of DSI index is consistent with It is the pattern of the drought process. According to the results, it can be acknowledged that the dust situation has always been affected by climate, but the relationship between drought and the DSI index has always fluctuated with respect to droughts and wetlands. However, different climatic parameters are different and their impact is different. In addition to human activities, the main role of wind in the amount of dust or the existence of another source of dust should be considered.
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