جستجوی مقالات مرتبط با کلیدواژه « گرد و غبار » در نشریات گروه « جغرافیا »

The aim of the present study is to dynamically model the spatial-temporal characteristics of dust in the south and southeast of Iran with REG-CM4 model using monthly dust data and RegCM4 data. For this purpose, the dust distribution of the IDW method along with the dust diagrams were plotted. The RegCM4 model was implemented with the paired Lambert image imaging system for 40 km horizontal separation with the paired chemistry model. The location of monthly and annual dust distribution shows the highest amounts of dust for the cities of Zabol, Bandar Abbas, Zahedan and Jask compared to Sirjan, Kahnooj and Lar stations. The highest frequency of dust in Sistan and Baluchestan (48%), Hormozgan (27%) and Fars provinces with 16% and the lowest frequency for Kerman province (9%). In general, the summer seasons (at Sistan station) and the winter (Kerman station) have the highest and minimum dust events, respectively. The time survey also has the highest amount of dust for the warm months of the year and the lowest for the cold months of the year. July at Zabol station and November and December at Sirjan station have the highest and lowest dust levels, respectively. The RegCM4 climate model also shows maximum dust on the southeast, south and south coasts for different variables.

Climatic factors and elements play a role in hydropower and soil type and are very effective in the creation and development of dust. The data of 13 stations (climatology, rain gauge, and synoptic) were used in a 33-year period from 1368 to 1400, and the water balance of the province was estimated using the Thornth-White method. Two stations, Manjil and Rudkhan Castle, were chosen as models for dust production. The area of Gilan province is 13,790.5 square kilometers and the geographical location of Rudkhan Castle is 37°06'N 49°16'E and the height above sea level is 1677m, its area is 1052/28 km and Manjil is 36°46'N 49°30'E, the height from the sea is 263 and the area is 29/1072 km2. Gilan province is in the north of Iran with a geographical length of 35/50 to 32/48 and a width of 27/38 to 33/36 in the north with the Caspian Sea, in the east with Mazandaran province, in the south with Qazvin province, and in the west with Azerbaijan and Ardabil. Soil moisture consumption in GIS environment was interpolated and mapped by kerjing method throughout Gilan, and two desired points (Manjil, Rudkhan Castle) with maximum and minimum consumption were determined on the map. Changes in soil moisture consumption are the most important icons influencing dust production. In drier climatic regions - Manjil - the consumption of soil moisture increases and the conditions for the separation of soil particles are provided. Despite the fact that the wind blows in Manjil most of the year, it causes the production of dust and it gets worse in the hot season.

Problems caused by climate change are one of the most important environmental crises and threats of human society, especially in urban environments. In the city of Tabriz and in recent years, due to the growth of the population, a lot of migration from other cities, traffic, the development of industries and production centers have caused an increase in the production and distribution of pollutants. Based on this, in this research, attention has been paid to the evaluation of the quality of dust occurrence in the years 2019 and 2018. The concentration of dust particles in different areas of the studied places varies depending on the geographical location, topographical, climatic conditions and also their origin, both internal and external. Based on the results obtained from the analysis of laboratory results and field studies, in the Tabriz region and during the research period, the concentration of lead metal in dust is moderate for adults and severe for children, and the risk of mercury metal for both the elderly and children. It has been intense. The adverse effects of cadmium metal have been very severe in children and adults. On the other hand, the high air temperature in the city center and the formation of thermal islands in it causes local winds from the suburbs to the city center. With the transfer of pollution from the suburbs to the city center by these winds, the pollution situation in the city center also increases.

One of the factors influencing the changes in the morphology of desert areas is the frequency of wind blowing due to the relative poverty of wind blowing and the surface and covering cover in these areas. Wind transport of sand is a complex process that depends on factors such as wind speed, amount of bare soil, dry air conditions, soil grain size, vegetation, local and external air system, short-term discharge, extent of deforestation, in an area. Based on this, the activity of winds in carrying out erosion is significantly related to the climatic conditions of each region. Wind erosion in desert areas is seen in the form of sand dunes.The importance of sand dunes studies is due to their impacts on water and soil resources, flora and fauna, human infrastructure, and roads. Therefore, for the purpose of basic planning, monitoring the speed and direction of movement or the expansion of sand dunes, due to the damages caused by it and especially the preservation of natural resources and human projects and facilities, is of special importance in the management of desert areas.

In this research, wind characteristics, dust characteristics, soil moisture and its effects on Zabol region are investigated. To check wind speed and direction, the data of Zabol anemometer station were evaluated in Wrplot software. Then, the sand graph was drawn in SandRose-Graph software in order to check the indicators of sand movement. The changes of dust and AOD index of the region were extracted in the Erthengine system and MODIS satellite images in the period from 2012 to 2023. Changes in soil moisture index in the region were also monitored using SMAP satellite images in Arth Engin.

In this research, the predominant wind direction of the region was determined as northwest-southeast by examining the wind direction of Zabol station. On the other hand, examining the trend of wind speed changes at Zabol station shows that the average wind speed at Zabol station has been increasing over the past 56 years; So that the average wind speed has reached from 2.5 m/s per month in 1962 to about 4.8 m/s per month in 2018, which shows an increase of 2.3 m/s during this period. The amount of sand carrying potential (DPt) at this station is 2079/8, which is estimated to be high based on Freiburger's and Dean's classification of wind energy at this station. The variability index (UDI) of wind directions for Zabol station is in the low variability group with the classification of unidirectional and channelized winds, which greatly increases the intensity of erosion and dust production. The highest amount of displaced sand (DSF) in Zabol station indicates the amount of sand particles transported in the region.
In addition to examining the characteristics of the wind in the region, the changes in the dust index (AOD) and aerosol were also carried out using MODIS sensor images in the environment of Erth Engin from 2012 to 2023, and the results showed that the highest percentage of dust with a size greater than 55 microns and less than 47 microns in the summer of every year and with the decrease in surface humidity and the increase in temperature and the occurrence of 120-day winds in Sistan, also the examination of the percentage of dust changes in the air in the 5-year period from 2018 to 2023 showed a significant increase. which indicates an increase in the percentage of airborne particles due to the expansion of wind erosion in the region.
Next, the soil moisture of the region was monitored using the Smap satellite image series, including changes in the percentage of surface and subsurface soil moisture in the Zabol region in the Google Earth Engine environment and the time period from 2015 to 2023, and the results showed that the highest percentage of soil moisture is from February to April. And the lowest percentage of soil moisture is from July to September, which corresponds to the occurrence of 120-day winds in Zabol region.

The results obtained from this research show that the main cause of dust occurrence in Zabol region is the increase in the wind speed in the region in the long term and the increase in dust supply centers around the region, which, along with climate change and the decrease in rainfall and the occurrence of drought, in the scale Locally, the drying up of Lake Hamon as a result of the Afghan government's non-compliance with the 1351 Kabul agreement regarding the introduction of 850 million cubic meters of water per year into Lake Hamon has had a significant impact on this issue. Considering the location of the dried Hamon lake in the northwest and west of Zabol city, and the direction of the prevailing wind, it can be said that most of the dust particles transported to Zabol originate from this area. Therefore, the only solution to the current situation of Zabol can be the restoration of Lake Hamon and stabilization of the sediments on the bottom of Lake Hamon. On the other hand, the presence of channelized and dominant northwest-southeast in the region has provided the conditions for the construction of wind power plants in this region, considering the criticality of the country's energy, which is used with proper planning and investment for this issue.

Urmia Lake is one of the largest saltwater lakes in the world, which unfortunately is drying up and has caused many dangers and concerns, especially in relation to salt dust in its dried areas. Therefore, in this research, we tried to investigate the relationship between vegetation and dust in the cities around Lake Urmia. Salinity in plants causes physiological disorders, salt stress causes growth, photosynthesis, protein, respiration, energy production, premature senescence, water reduction in plants. Considering these effects, it was tried to evaluate the overall health of plants by using related indicators including NDVI, CIre, GCI, CRI2, NDWI, NDII, MSI, PSRI. These indicators evaluate the amount of plant water, plant water stress, photosynthesis capacity, plant growth and water deficit, the amount of chlorophyll, nitrogen and pigments, which are related to plant energy and health. According to these indicators, the health of plants is generally in a favorable condition, and mostly the highest numerical values of the indicators were assigned to gardens. Using Landsat and Sentinel 2 images and the NDVI index, the vegetation changes of the region were determined in the period from 2010 to 2020, and then using the MERRA-2 database, the amount of dust concentration was also extracted for the mentioned years. The results showed that the average NDVI in the studied area follows a constant trend with an overall average of 0.2957 and sometimes it increases or decreases due to the influence of external factors such as dust. Based on this, the highest (0.3495) average NDVI is related to 2018 and the lowest (0.2579) is related to 2013. Also, two methods of linear and logarithmic regression were used to investigate the relationship between vegetation cover and dust, and the results showed that based on the linear (0.7703) and logarithmic (0.7915) regression, the highest coefficient of explanation between the two mentioned indicators was in May. have been.

In deserts and dry areas, sudden changes in temperature cause strong winds and as a result cause the phenomenon of dust. The purpose of this research is to investigate the relationship between the occurrence of dust storms and the North Atlantic Oscillation (NAO) index at selected stations in the west and southwest of Iran (Abadan, Bostan, Ilam, Dehloran, Kermanshah and Sarpol-E-Zahab). For this purpose, we used the codes of days with dust storms, horizontal visibility of less than 1 km, data related to index values (NAO) during the statistical period 1987-2022, and satellite data including dust optical depth index (AOD) obtained from the productions of the gauges of 2000-2017 MISR and 2002-2022 MODIS periods. The results of the correlation coefficients showed that there is a relatively strong inverse relationship between the NAO index in the negative phase and a weak direct relationship with dust in the positive phase, and between 51% and 70% of the dust occurrences were simultaneous with the positive phase. The graph of changes in the time series of the indices in the two negative and positive phases showed that the value of the AOD index increased from west to southwest, which is evident in the Abadan station. According to the index produced by the MISR sensor in the years 2011 and 2015 in the positive phase and in the year 2008 in the negative phase, the peak of dust storm activity in all stations and its lowest value are related to the Sarpol-E-Zahab and Kermanshah stations in the years 2002 and 2004, respectively. According to the Deep Blue index obtained from the MODIS sensor, the positive phase of 2022 and the negative phase of 2009 can be separated as the peak of dust storms. The results of the Wind rose and HYSPLIT models showed that the direction of dust storms entering Abadan, Bostan and Ilam stations was from the northwest and southwest and in Dehlorn, Kermanshah, and Sarpol-E-Zahab from the west, and the storms with external origin in these stations were influenced more by the countries of Iraq, Syria and Saudi Arabia.

Dust storm is a complex process affected by the earth-atmophere system. The interaction between the earth and atmosphere is in the realm of the climatologists and meteorologists, who assess atmospheric and climatic changes, and monitor dust spread. Dust is the main type of aerosols which affects directly and indirectly radiation budget. In addition, altogether they affect the temperature change, cloud formation, convection, and precipitation. The most important studies about dust analysis have considered the use of remote sensing technique and global models for analyzing the behavior and dynamics of dust in recent two decades. To achieve such a goal, this paper has used MODIS and NDDI data to study and identify the behavior of atmospheric dust in half west of Iran.

The western region of Iran is the study area. The data used in this study are divided into two categories: ground-based observations in 27 synoptic stations extracted from the Iran’s Meteorological Organization during the period (1998-2010) and satellite MODIS images during the first to fourth days of July 2008 as atmospheric dust extremes. Data was analyzed by using ArcGIS and ENVI software and NDDI index. 

According to results, interpolated map for the number of dusty days during the study period over the western half of Iran showed that the scope of study area does not involve an equal system aspect quantity of occurrences. The number of dusty days occurrences increase from north toward south and the sites located in northern proportions of the area have experienced lower dust events. In contrast, maximum hotspots are occurring over southwestern sites such as: Ahvaz, Ilam, Boushehr and Shiraz. Therefore, principal offspring of dust input has been out of country boundaries and arrived at distant areas. Also, based on results obtained using satellite remote sensing images and applied NDDI index, maximum of intense dust cover is observed over Fars, Ilam, Boushehr and Ahvaz provinces on the first, second, third and fourth of July. However, the lowest rate of index situated in extent far such as: East and West Azerbaijan provinces. Thus, parts located on the north of the study area experienced less dusty days and the maximum dust cores were located in the southwestern (mostly Khuzestan). The long-term results were consistent with the daily average of NDDI index in the whole study area and indicated the hotspot areas (Ilam, Ahvaz, Omidyeh, Bushehr and Shiraz) during the first to fourth days of July 2008. However, the level of dust cover in the region has reduced when a wet and cloudy synoptic system passes over the central and northwestern parts of the study area.

The climatic interpolated map interpretation indicated that increase of dust concentration based on ground-based stations, which are consistent with dust concentration, is overshadowed by the latitude and proximity of sources of dust source in the Middle East. Also, the long-term climatic results of ground-based observations were consistent with the NDDI index calculated on dust extremes in the whole study area and in the southern areas (Ilam, Ahvaz, Omidyeh, Bushehr and Shiraz) during study days of July, 2008. Therefore, dust occurrence increases from north to south and the maximum hotspots over southwestern confirm the proximity of the south western region of Iran to deserts and sedimentary plains and their direct relationship with dust sources in the Middle East. These regions highlight the volume and expansion of dust outbreaks, which were well detected due to the satellite imagery and spectral characteristics of MODIS for monitoring changes in the dust phenomenon.Overall, the use of satellite remotely sensed data/images not only cover the ground-based observation datasets gap to identify, highlight, and analyse the dust phenomenon, but also takes a much more geographical approach in analysing environmental hazards such as dust. It is also suitable for studies of atmospheric compounds such as atmospheric aerosols.

Soil and air are two essential elements in the life of creatures on the earth. Their interaction in certain conditions can cause many risks; among these dangers, dust storms can be mentioned. Under the conditions of dust storms, a large amount of dust is emitted in the air and the horizontal visibility is reduced to less than 1000 meters. Therefore, due to the important role of the dust phenomenon, it is highly necessary to understand the spatial-temporal changes and to analyze their long-term variations. Jazmurian region, located in the southeast of Iran, between the two provinces of Kerman and Sistan and Baluchistan, has become completely dry and turned into a desert due to drought and construction of numerous dams, and has turned this region into one of the key areas of dust production in the country. Therefore, the purpose of this study is to investigate the temporal-spatial changes of dust storms in relation to climatic parameters in Jazmurian wetland, which is of particular importance in order to properly manage this area to face the problems caused by dust storms.

In order to carry out the present research, the meteorological data related to the synoptic stations located in the Jazmurian wetland area for a period of 20 years (2000-2020) were received from the Iranian Meteorological Organization. Climatic data used in this research include temperature, precipitation, relative humidity, wind speed and direction, horizontal visibility, and remote sensing data including Aerosol Optical Depth (AOD) and Normalized Difference Vegetation Index (NDVI). The research method uses a combination of statistical analysis, observation and remote sensing. In order to check the AOD and NDVI, the monthly data of MODIS sensor was used. In this study, 12 synoptic stations that had the longest and most complete statistical periods were used in order to identify the temporal-spatial changes of dust occurrence in Jazmurian wetlat. The Mann-Kendall test was used to examine the trend of time changes. The slope of the Sen estimator was used to check and confirm the accuracy of the trend changes. In order to better understand the spatial distribution pattern of dust events in the Jazmurian wetland basin, the inverse distance interpolation method (IDW) was used. Also, Pearson's spatial correlation analysis was used to investigate the mutual effects between the indicators.

The 20-year average review of the indicators showed that the maximum value of aerosol optical depth in the studied area was 0.3, which is seen in the central part of the wetland. The vegetation index also showed that the maximum value of this index was 0.2, which covers most of the northern, northwestern and western parts. Examining the average rainfall trend showed that the maximum and minimum rainfall in this period are about 219 and 85 mm, respectively. Meanwhile, the 20-year average temperature survey showed that the maximum and minimum temperatures were 28.7 and 17.2 degrees Celsius, respectively. The fact that the maximum rainfall is in the northern and western part is in harmony with the minimum temperatures in these areas. The examination of the average wind speed showed that the maximum speed was 3.6 m/s, which was mostly in the central, west and northwest, south and southwest parts. The results of the wind direction index showed that the lowest wind direction is in the northern parts of the region and the highest wind direction is in other parts of the Jazmurian wetland basin. The maximum humidity in the studied area is 43.73%, which is mostly seen in the north, northwest, west, south, and southwest parts.  Examination of the horizontal visibility index showed that the maximum amount of horizontal visibility was in the northeastern and northwestern parts of the region. Also, the process of changes in the Mann-Kendall test showed that the annual averages of the indicators of wind direction, wind speed and horizontal visibility have been increasing with a positive slope, and the trend of changes in the relative humidity index has a negative slope and indicates a decrease in the period of 20 years. The results of the correlation analysis (at a significance level of 5%) showed that the highest correlation of the optical depth index was with the wind direction parameter and the lowest correlation was with the relative humidity index.

The growing trend of the emission of dust particles caused by the phenomenon of wind erosion in recent decades has caused major concerns at different regional, national and global levels. Therefore, it is necessary to understand the temporal-spatial changes of the dust caused by these events in order to reduce their adverse consequences in different regions. Accordingly, in this research, with the help of this knowledge, information related to the optical depth of particles in the air (AOD) and the vegetation cover index (NDVI) were investigated using the MODIS sensor satellite data. Using the meteorological data received from the website of the National Meteorological Organization, the climatic data of rainfall, temperature, relative humidity, horizontal visibility, wind direction and wind speed were evaluated in the period of 2000-2020 and finally the correlation between the AOD index and other climate parameters was evaluated. The results of the optical depth investigation showed that the maximum optical depth is located in the central parts of Jazmurian wetland. The trend of changes in rainfall and temperature indicators also showed that the trend of these two parameters was increasing; this increase in temperature is more noticeable. Correlation investigation between optical depth and other parameters showed that the highest correlation of optical depth index was with the wind direction parameter and the lowest correlation was with the relative humidity index. In general, we can conclude that the optical depth of airborne particles is highly dependent on environmental factors, which is more evident in arid and semi-arid areas, especially in Iran and the Jazmurian wetland area. In recent years, the area of the wetland has acted as a source of dust. Therefore, by using the remote sensing data obtained from the MODIS sensor and the climate data, it is possible to examine and analyze the trend of dust changes in the units of time and space.

Climatic phenomena in different regions of the world are different in relation to the geographical characteristics of each region. Dust is one of the dominant atmospheric phenomena in desert and semi-desert regions of the world. This phenomenon is related to air pollution in most parts of Iran with dry climate, including Birjand in eastern Iran. The origin and direction of dust in this area are varied in the year, and knowing them helps urban risk management, forecasting and desertification. In this study, Landsat satellite images were used to determine the origin of dust in the period of 1955-2017. The dust day was defined based on the classification of Shao and Dong with code 06 and 07 with horizontal visibility of less than 10 km, and revealed with BTD and TDI index. To determine dust atmospheric patterns, grid data from NOAA was used, and dust trajectories were carried out with the HYSPLIT model. The results showed that the most dust days in 1963 and 2008 (45 years), with 148 and 128 days, respectively, which mainly occur in the warm season and July. The 120-day winds of Sistan in the east of Iran plays a major role in transporting dust particles and air pollution in Birjand from the east and northeast from the deserts of Central Asia, Turkmenistan, Afghanistan, Khorasan Razavi plains and interior plains. But in the cold period of the year, Siberian cold masses from the east, cold fronts (migrating anticyclone), occluded fronts and low pressures from the northwest, west and southwest by passing through the central plains of Iran and sometimes the deserts of Syria and Iraq causes dust in the upper levels of the atmosphere. In all these centers, the occurrence of particles and pollution of cities prevails during periods of drought.

Urban environmental pollution by heavy metals causes undesirable changes in the physical, chemical, and biological properties of life's main sources including water, air, and soil. This study has been carried out to map the spatial distribution concentration of heavy metals copper, zinc, lead, and cadmium and to evaluate the ecological and environmental hazards of these pollutants, by pollution indices mCd, Igeo, RI, and Cf indices in Zahedan city. In this research, 90 samples of deposited dust were collected by using a systematic random sampling method, and the concentrations of these metals were measured. To the model of the spatial distribution of heavy metals, the kriging method was used in Arc GIS. The results of heavy metals concentration measurements showed that the highest mean concentration was obtained for Pb 270.51 (mg. kg-1) and the lowest mean concentration was obtained for Cd 20.74 (mg. kg-1). Also, average concentrations of lead and cadmium were higher than the standard level in the soil. Also, the results of the Pearson correlation coefficient showed that there is a significant correlation between zinc and cadmium. Based on the results of the contamination factor and the potential environmental risk index, the copper and zinc showed low pollution range, lead high pollution range, and cadmium very high pollution range. Geoaccumulation index showed moderate pollution class for cadmium and high pollution class for copper, lead, and zinc. According to the spatial distribution maps, the highest concentrations of metals were observed in the city center and main roads which showed the role of human activities in the distribution of these elements.

One of the critical factors dust sources by less consideration is the role of geology and geomorphology as a source of dust emission. Geological units are one of the factors involved in the release of dust particles and the production of sediment.  Lithological components with high sensitivity to alteration, weathering, and erosion, play an influential role in the emission and distribution of dust particles. Based on research, Sarakhs County is one of the critical corridors of wind erosion and dust storms in Iran that is affected by 120-days’ winds of Sistan The sensitivity of the geological units to wind and water erosion in this area categories from medium to very high. To identify the chemical elements of the geological units and their roles in dust emission, soil samples were collected from the surface, and sub-surface layers of the geological units and airborne dust were also collected from the atmosphere. Samples were analyzed by induction spectroscopy to determine their chemical elements. To identify the origin of dust and its relationship with geological units and also their classification, factor and cluster analysis was performed. The results of factoring and clustering analysis showed the Sarakhs region with chemical elements sodium, zinc, lanthanum, arsenic, niobium, cadmium, nickel, lead, zinc, lithium, strontium, sulfur, sodium is in factor one with an evaporative and chemical origin, and with elements of aluminum e, iron, cobalt, thorium, manganese, boron, and titanium is in factor two with a detrital and terrestrial origin. Also, the chemical elements of dust in rural areas of Bazangan, Shorlugh, Baghbghoo, Padeh, and Baghak are in the same group with the geological units of Abe-Daraz, Chehel-e-Kaman, Quaternary deposits, bitter water, and Khangiran and have a common origin. The chemical elements barium, arsenic, sulfur, thorium, nickel, lithium were introduced based on enrichment factors with human origin (chemical-evaporative).

Dust storms caused by erodible surface sources, such as deserts, have been one of the major natural disasters in recent years, affecting countries in the Middle East, including Iran. One of the major factors to formation the dust storms is the strong wind flow that can be created in the presence of low pressure systems in the potential. Therefore, the study and identification the atmospheric patterns can be effective in predicting these storms. One way to study dust storms is to use numerical models that can be used even for times when appropriate data is not available and also to predict these types of storms.

After statistical study of the phenomenon of "dust" and the factors affecting it in the Jazmourian basin, a severe and widespread event of "dust" in the Jazmourian basin is investigated. Then, to investigate the prevailing atmospheric currents in the region, the HYSPLIT model is implemented as a matrix and in a leading way. In the implementation of HYSPLIT model, GDAS meteorological data with horizontal separation of 0.5 degrees have been used. Using the output of this model, it is possible to study how dust particles are transferred from this area. Finally, each of the studied dust phenomena is simulated using the WRF-Chem model to determine how the dust is emitted and transmitted in the region.

Leading HYSPLIT model output for November 28, 2016 UTC12 clock which was executed as a matrix with GDAS data with 0.5 degree horizontal separation for 36 hours at a height of 100 meters. The results showed that the particles from this region were affected by northwestern currents and were transferred to Sistan-Baluchestan province and the border between Iran and Pakistan. Aerosols optical depth of the output particles of the WRF-Chem model at UTC12 on November 24, 2016. Values higher than 0.5 indicate a high amount of suspended particles in the atmosphere in the study area. At this time, the highest light depth of particles is in the Strait of Hormuz and Qeshm Island, but the concentration of particles in a large part of Jazmourian region is between 0.4 to 0.6, which can indicate the presence of dust particles in the atmosphere. The results also show that the concentration of "dust" on the Oman Sea and the Persian Gulf is higher than 5000 micrograms per cubic meter. Also, the concentration of "dust" in Jazmorian region is high and is higher than 1500 micrograms per cubic meter. Also in some areas, the concentration of "dust" is more than 5000 micrograms per cubic meter.

In the present study, using the outputs of the WRF_Chem model, the dust phenomenon and its characteristics in the southeastern region of Iran have been identified. According to the results, the WRF_Chem model provides a reasonable estimate of the weather in the study area in terms of scale and time changes. By producing dust particle concentration distribution maps, areas of the simulation basin that have the maximum particle concentration were identified as the main sources of particle emission. In general, the performance of the WRF / Chem numerical model in this study confirms the applicability of this model in modeling and forecasting air quality, especially for air vents produced from natural emission sources such as erodible areas of deserts. The results showed that the studied dust phenomenon (November 24-27, 2016) dust particles from Jazmourian basin, were affected by northwestern currents and were transferred to Sistan and Baluchestan province and the border between Iran and Pakistan.Keywords: simulation, Dust storm, WRF/Chem model, MODIS.

In the present study, using the outputs of the WRF_Chem model, the dust phenomenon and its characteristics in the southeastern region of Iran have been identified. According to the results, the WRF_Chem model provides a reasonable estimate of the weather in the study area in terms of scale and time changes. By producing dust particle concentration distribution maps, areas of the simulation basin that have the maximum particle concentration were identified as the main sources of particle emission. In general, the performance of the WRF / Chem numerical model in this study confirms the applicability of this model in modeling and forecasting air quality, especially for air vents produced from natural emission sources such as erodible areas of deserts. The results showed that the studied dust phenomenon (November 24-27, 2016) dust particles from Jazmourian basin, were affected by northwestern currents and were transferred to Sistan and Baluchestan province and the border between Iran and Pakistan.

Sandstorms are natural events that occur in arid and semi-arid regions of the world, especially in subtropical latitudes. The vastness of deserts around the world indicates that these areas have been important sources of dust storms throughout history, but in recent years, human activities have also created another source on the edge of deserts in semi-arid regions. These have been stable. The use of pebble mulch, which is a clear example of inspiration from nature in the field of paving (Hamada). In addition to gravel, one of the materials that can be effective in this way is steel slag, which seems to be usable as a coating to keep particles sensitive to erosion of sandy areas. It also seems to have the ability to create a suitable substrate for the establishment of tropical or native vegetation.In addition, slag seems to have the ability to treat eroded particles and can play an important role in the treatment of Aeolian sediments. Knowledge of the amount and type of particles treated by mulch enhances our overall understanding of its impact on controlling wind erosion and the impact of sediments on soil formation and production in covered lands.

In this study, while determining the threshold of wind erosion in work areas by non-oil sandblasting and mulching in desert areas studied in an area of 1 to 2 hectares (depending on the specific conditions of the region, facilities, natural features and other characteristics of the region) as A research pilot was used to compare their performance in terms of soil containment and stabilization, as well as the costs incurred for each method, and to introduce them to the executive departments of the country for each region according to the specific characteristics of that region.

Two separate factorial experiments in a randomized complete block design with three replications using natural almond pebbles with a density of 75% in Fesaran plain and Mobarakeh Steel Company almonds with a density of 25 and 50% density compared to the control as mulch Were used. The site of the first experiment was Site 1 with an area of about one hectare located in the desertification station of Segzi plain (Figure 1). Factor A was the uniform condition of the area with uniform mulch spraying treatment with a density of 25%, 50% and control. Factor B were two types of sediment traps (tray and polygonal). The plots had dimensions of 20-30 square meters. The shape of the plots was chosen so that the length of the plots was in the direction of the prevailing erosive wind. The distance between the two plots was considered 30 meters so that the effect of mulching on the other plot would not be left. The location of the second experiment was in the Fesaran area. In this experiment, factorial in the form of a randomized block design was used. Factor A mulching with 75% density of pebbles and control and factor B were two types of sediment traps (tray and polygonal).

The results of this study showed that mulch reduces the level of wind contact with the soil and increases the roughness and therefore can control wind erosion. Mulch 0 performs two important actions in controlling wind erosion, first it can relieve soil from stress it protects against wind and wind erosion, and the latter can trap wind-blown particles. Segzi and Fesaran plains of Isfahan have erodible sediments and also the movement of wind sand particles. These sediments have a wind erosion threshold of 4.6 meters per second, which is very prone to wind erosion. The treatments in this plan increase the roughness of the soil surface and reduce the wind speed near the ground surface, and as a result, the amount of soil loss is also reduced. As the mulch density increases, less soil erodes due to less area being exposed to the wind. Based on this, the use of pebble mulch, which is a clear example of nature inspiration in the paving areas (Hamada) with the effect of zero (control) and 75% gravel cover density on the area sensitive to wind erosion in Fesaran plain in Isfahan Done. The type of pebbles selected is almond size and the size of gravel and rubble, which was supplied from the nearest sand mines in the region. But in addition to gravel, Mobarakeh steel slags with almond sizes (in order to study and compare costs) with the view of waste with a very large production volume with the effect of zero density (control), 25%, 50% were also used in Segzi plain. In order to create winds with a certain speed at a certain time, a wind erosion measuring device, which is a kind of portable wind tunnel, was used. The lands of mulching sample with different densities are affected by different winds from different directions. The data obtained from the factorial statistical experiments were examined in a completely randomized block design. The results showed a significant difference in the effect of pebble mulch in reducing wind erosion in all studied areas and at a level of less than 1%. Comparison of the effect of molten densities of Mobarakeh steel slags showed that the largest difference between the two densities was 25% and control. The results obtained from the collected data of wooden indices (scavenger traps) in Segzi plain show an average of 1.9 years of wind from the soil surface and in Fesaran plain show an average of 1.2 kg per square meter of wind from the soil surface And the statistics obtained from the tray sediment trap had a better performance than the plastic polygon sediment trap and showed a significant difference. In these two areas, the volume of creep particles is higher and a very large amount of dust has accumulated in the sediment trap. Trap in the process of creeping or jumping by the wind

In recent years, the dust storm has been caused extensive economic, health and environmental damages. Dust storms are lower atmosphere events that result from wind erosion liberating sediment participles from the ground surface. Sand storms occur relatively close to the ground surface, but finer dust particles may be lifted kilometers high into the atmosphere, where strong winds transport them long distances. Increasing Dust storm events have several negative effects on the environment. Airborne dust causes or aggravates human health problems. Chronic exposure to fine particulates is associated with premature death due to cardiovascular and respiratory disease, lung cancer, and acute lower respiratory infections. Inhalation of fine dust particles exposes individuals not only to hazardous fine mineral particulates, but also to harmful combinations of pollutants, spores, bacteria, fungi, and potential allergens carried along with mineral dust. Poor visibility, sand movement and deposition as a result of SDS also increase incidences of road accidents and aviation hazards.For these reasons, enough knowledge about the origin and occurrence time of dust storms could be effective in its damage reduction. The main objective of this research was the source identification of Karaj dust storm events directionally. For this purpose, Dust events in about two decades (2000-2018) were extracted from meteorological data of Karaj synoptic station. PM10 data from Karaj air quality monitoring stations and MODIS Aerosol Product were used to verify dust events that were determined in the previous step based on availability. The MODIS Aerosol Product monitors the ambient aerosol optical thickness over the oceans globally and over the continents. Furthermore, the aerosol size distribution is derived over the oceans, and the aerosol type is derived over the continents. CPF and DRS diagrams and HYSPLIT model were applied for source identification. The Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) is a computer model that is used to compute air parcel trajectories to determine how far and in what direction a parcel of air, and subsequently air pollutants, will travel. HYSPLIT is also capable of calculating air pollutant dispersion, chemical transformation, and deposition. The model derives its name from the usage of both Lagrangian and Eulerian approaches. The Conditional Probability Function (CPF) calculates the probability that a source is located within a particular wind direction sector CPF is useful in determining the direction of a source from a receptor site. The DRS approach, the ratio of the concentration contribution weighted-wind sector abundance to the overall wind abundance in a wind sector is used to assess the pollution potential of the source in that sector.Based on meteorological data and considering AOD images, the maximum and minimum numbers of the dust storm in the year had been recorded in 2008 and 2000, respectively. Also, the most dust storm occurred in summer. The most frequent dust storms were observed from April to August. Among these months, June has the most frequency of dust storms. The dust storm events increase from the beginning of the warm-season and reduce in fall when the wet and cold season starts.Results of windrose, CPF, windrose of dust events and DRS showed the important direction in dust events of Karaj were NWW, NW. HYSPLIT results for 72 h back trajectory and dust events of Karaj in three altitudes above ground level (10, 500 and 1000 m) showed the dust origin in NW and W of Karaj had the most share on Karaj dust storm events. For example, two dust events results were presented. One of them belongs to local dust events and another for regional dust events. The results helped to identify the most important dust event origins. In overall, the results of directional source identification of Karaj dust storm showed the sources that are located in W of Karaj (in local events) and IRAQ and the north of Saudi Arabia (in regional events) have important role to increase particulate matters (PM) and decrease air quality of Karaj. In addition the results of investigation of MODIS Images for studied dust events that were the real snapshot of the earth showed the results of HYSPLIT is reliable to determine the dust storm sources. For example in 2014/4/13, MODIS image showed the source of this event was from north of Saudi Arabia and the passed above SW border of IRAN and the arrived to Karaj. This event have long journey more than 1000 km and showed the importance of dust origin that are located in other countries to air quality of Karaj. In conclusion, directional source identification of dust storm was successfully and very rapid method to understand the most important sources in any events. This methodology can be used in other studies that have concern about source identification for dust storm.

The crisis of climate change, and especially dust phenomenon, has become more apparent in the last decade as it now involves all aspects of the society, especially farmers and villagers. The growing number of natural disasters has sounded the alarm for the agricultural community in Kermanshah province. In this province, most people are working through agriculture and the slightest change in the climate can have an immediate impact on the agricultural sector, thus leading to bigger problems such as immigration, and the country's lack of independence in meeting food needs and resolving social, economic, cultural, or even political issues. Accordingly, dust management and planning for it can be effective when we identify and classify the areas affected by dust based on the intensity and concentration of fine dust particles.Dust phenomenon has imposed a lot of costs on the agricultural, economic, and health products of people living along the Zagros Mountain Range in recent years. Zoning of the affected areas can be a tool for planners to deal with priorities, determine an optimal land use, and provide warning systems and protection, etc. in arid and semi-arid regions, especially in the involved cities. Although the issue of dust is an almost uncontrollable phenomenon, it is at least possible to know the time table and circulatory patterns, based on which infiltration of particulate matters from the regions occurs. The related infrastructure is ready to deal with this phenomenon. Therefore, it is necessary to identify the areas that suffer from the most damage caused by fine dust and effectively contribute to the reduction of its destructive outcomes. 

In this research, quantitative, applied, and descriptive-analytical approaches were taken in terms of paradigm, objective, and data collection, respectively. To conduct this study, 14 synoptic, complementary synoptic, and meteorological stations working through the complete and longest statistical period were selected during a common statistical period of 16 years (2002-2018). At the meteorological stations, two-digit codes were utilized to report on the atmospheric phenomena like precipitation type, including precipitation with thunderstorms and snowstorms, as well as the amounts of dust or sand. These codes started from 00 and continued up to 99, each of which represented an atmospheric phenomenon. Code 06 was for dust phenomenon. The frequency of this code was different from those of the other codes when filtered in Excel software, after which its annual frequency reported in each of the selected stations during the 16-year statistical period was calculated by SPSS software. In the final stage, zoning patterns were formed and the information layers were analyzed in the ArcGIS software environment. 

Based on the annual frequency of airborne dust storms, dust pollution in the cities of Kermanshah province fell into 3 categories: very severe, severe, and moderate. The cities of Sarpol-e-zahab, Qasr-e-Shirin, Paveh, Gilan-e-gharb, and Thalas-e-Babajani fell in the category of very severe frequency; Kermanshah, Javanroud, Ravansar, Dalahou, and Islamabad cities had a severe frequency; and Sahneh, Kangavar, Songor, and Harsin cities were categorized as having a moderate frequency. There was almost a big difference between the first category and the second and third one in terms of frequency of dust days. The reason was that the first group of stations were located in the vicinity of Iraq, Saudi Arabia, Syria, Jordan, and Kuwait, which were the sources of dust spread over the western regions of Kermanshah province. Also, the drought and lack of vegetation in these regions leading to the separation of soil particles were known as the aggravating factors contributing to the occurrence of more dust days in this group. However, the stations in the second and third districts had fewer dusty days due to being far from the mentioned dust centers. 

The agricultural sector is one of the most important economic sectors in all developing countries, which, in addition to creating jobs for people, is responsible for producing the food needed by the members of the society. Agricultural activities can lead to independence in other aspects. Apart from all the benefits of agricultural activities for a country, it is important to consider what happens if a factor has a negative impact on them. Unfortunately, we have witnessed dust occurrence in the country, especially in the western and southwestern regions in the last decade. The effects of dust on agriculture can be a threat to the health of producers and consumers, as well as the environment and natural resources. On the other hand, most people make a living from agriculture and animal husbandry in Iran, particularly in the study area. Therefore, long-term dust would destroy people’s productive resources in the study regions and thus reduce food production and independence. In this research, we sought to conduct zoning of the areas affected by dust phenomenon in Kermanshah Province. This way, we could identify areas undergoing the most damage from dust. Eradicating the causes and factors leading to severe damages triggered by dust phenomenon can be the basis for policy-makers and developers of appropriate programs to prevent natural and priority crises and deal with them in strategic decision-making and planning. The results revealed that the cities in the western and eastern regions of Kermanshah province had the highest and lowest frequencies of dust occurrence during the last 16 years, respectively. 

In recent decades, dust storms have intensified due to climate changes, including drought and human interventions. In addition to removing soil particles, dust brings storms bring about severe economic, social, and health problems. Due to its strategic conditions – including its status as an industrial and agricultural hub and the province hosting more than 29 million Iranian and international pilgrims, especially during the seasons and months with specific holidays – should be prioritized in the examination of dust storm frequency. The purpose of this study was to examine and track the frequency of dust storms and analyze the effect of climactic changes on them through the investigation of drought trend as well as the trend of changes in the land surface coverage percentage during the statistical analysis period. The results of counting the dust codes showed that dust storms with local origin had the highest frequency. According to the monthly analysis, Sarakhs and Mashhad stations had the most dust phenomena, with the most dusty days in the study area during summer and spring seasons, especially June and July months. The results of regression analysis of drought index and the monthly local dusty days indicated the existence of a significant, positive relationship between dust increase and drought intensity in Mashhad and Sarakhs stations during the statistical period of 27 years at 99 percent confidence interval. Finally, in the light of the results obtained from the examination of the land surface changes, it is recommended that land use plans be used along with short-term methods of soil stabilization in order to reduce the economic damages and preserve people’s health against dust during busy months and seasons so as to achieve the goals of long-term methods.

Dust is one of the most common climatic phenomena in arid and semi-arid regions of the world The phenomenon of dust is a natural occurrence and occurs in areas with vast areas of arid and desert areas, Lack vegetation and other surface coatings. Due to its presence in the arid and semi-arid belt of the world, Iran is constantly exposed to local and synoptic dust and dust systems. In recent years, the phenomenon of dust in the Middle East has been increasing, Because it is one of the five regions of the world that has the highest dust production . Long periods of drought and inappropriate interventions in nature can increase the likelihood of this phenomenon.
In recent years, the trend of dust events in the west and south of Iran, especially in the spring and summer, has increased dramatically .This phenomenon is affected by certain atmospheric conditions and its distribution can affect the temperature, temperature, precipitation and atmospheric circulation conditions of the area during the months of the year.
In this study, data of 56 years old (during 1961-2016) precipitation, temperature and dust on daily scale from 30 synoptic stations in the west and southwest of Iran were obtained from the country's meteorological organization. In line with this study, MATLAB, ArcGIS and SURFER softwares have been used. In order to analyze the information, recognition of fluctuations and the relationship between dust, temperature and precipitation have been used.
Recognition of fluctuations and the relationship between dust, temperature and precipitation are investigated using regression, spectral analysis and Pearson correlation coefficient. Then it is represented by trend maps, cycles, and correlation tables. The results for the West and Southwest of Iran have been obtained and explained in detail.
The study of the spatial distribution of the trend shows that most of the stations studied in the dust and rainfall have an increasing trend and have been in a decreasing trend temperature. Spectral analysis of dust, dry days, and temperature showed that short-cycle cycles in addition to the most frequent distribution, showed a higher probability of occurrence than long-term periods. In most of the stations studied, the correlation of dust with temperature and dry days has a positive and direct, relationship with the rainfall has a negative and inverse relationship. The local mororan analysis for the spatial autocorrelation of dust with dry days in the western, northwest, northern and parts of the east of the study area has shown a high value cluster pattern (positive spatial autocorrelation). The spatial autocorrelation of dust with precipitation in the northeastern, eastern, and small parts of the southeast and west of the study area has a high cluster pattern (positive spatial autocorrelation). The spatial autocorrelation of dust with temperature in the eastern, western, and small parts of the south of the range has a high cluster pattern (positive spatial autocorrelation).

Introduction :

Jazmourian basin in southeastern Iran includes parts of Kerman and Sistan, and Baluchestan provinces. This region is one of the sources of dust production in southeastern Iran. The maximum dust emissions in the Sistan region occur in eastern Iran, southwestern Afghanistan, and Pakistan in the summer, and these storms load dust from local scales to regions. Vegetation and its type also play an important role in the severity of dust. There is positive feedback between precipitation and dust emission from the surface; This means that the dust from desert areas reduces rainfall and decreases rainfall, causes the soil to dry out, and further increases dust. In addition to the effect on rainfall, the presence of dust is also effective in its spatial distribution.

 In this study, first, using the optical depth data of the MISR sensors of Terra satellite with a horizontal separation of 0.5 degrees, the monthly and seasonal average optical depth of the aerators in the Jazmourian basin is determined. In order to study the trend of AOD change, the average AOD regions of TODRA satellite MODIS sensor are shown annually in the period 2000 to 2020, and the regression line slope was calculated by age estimation method and Mann-Kendall method with 95% and 99% confidence levels. The amount of vegetation changes in the region has been studied using the annual average of the NDVI index in the Jazmourian region. Since precipitation is one of the factors affecting the occurrence of dust events, the average annual precipitation rates of the TRMM satellite have also been studied. Finally, to investigate the effect of vegetation change on dust, the correlation between the average annual data of AOD and NDVI data and the correlation between the average annual rainfall data and NDVI was calculated to investigate the effect of annual rainfall on vegetation.

Results :

 The monthly average values of the optical depth of air vents were in the period 2000 to 2020. In January, AOD values in the center of the Jazmourian Basin, located on the border of Sistan and Baluchestan and Kerman provinces, are slightly higher than in other parts. From February to July, an increase in AOD is observed in the region so that in large parts of the Jazmourian Basin, the average optical depth of air vents in this month has reached about 0.6. Since August, AOD values have gradually decreased until December; only in the central areas of the basin, small amounts of AOD are observed. As expected, the maximum AOD in this region is observed in summer, and then in spring is in second place. The amount of AOD has decreased significantly in autumn and winter. According to the results, NDVI values were low in years when the mean optical depth of the particles was high. For example, in 2008 and 2012, when AOD values were higher than in other years, the average annual NDVI values decreased. Interestingly, the average annual values of optical particle depth in 2020 and 2017 were lower than in other years, but in the same years, the average annual NDVI values are higher than in neighboring years. The results show that in the years when there is an increase in rainfall in the region, an increase in vegetation and a relative decrease in AOD compared to previous years are also observed. It should be noted that in some years, with increasing rainfall and vegetation, the amount of AOD has not decreased much that it can be said that the amount of AOD, in addition to the activity of local dust sources, is due to dust particles from other areas to the study area and AOD changes only Not due to changes in rainfall and vegetation in the area.

The average monthly light depth values of air vents in the period from 2000 to 2020 show that in January, the AOD values in the center of Jazmourian Basin, located on the border of Sistan and Baluchestan and Kerman provinces, are slightly higher than other sectors. From February to July, an increase in AOD is observed in the region so that in large parts of the Jazmourian Basin, the average optical depth of air vents in this month has reached about 0.6. From August, when small amounts of AOD were observed only in the central areas of the basin, AOD values gradually decreased until December. Also, the average monthly AOD values in the region in the period 2000 to 2020 show that the highest AOD values in July are related to 2003 and 2001, and in June are related to 2008, which is significantly different from other years. Examination of the seasonal average values of the optical depth of air vents in the period under study shows that the maximum amount of AOD in this region is observed in summer and then spring, and AOD values in the autumn and winter seasons have decreased significantly.

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 Kundalchr('39')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.