In recent years, by intensified desertification in Iraq, Saudi Arabia and Syria, dust storms have affected different aspects of people's lives over the West and southwest of Iran. Atmospheric aerosols affect public health, air quality, energy balance of the Earth and the hydrological cycle. Thus, knowledge of the spatio-temporal dust storm's distribution characteristics is extremely important to quantify these effects. By increasing in dust storms in the West and southwest of Iran much discussion about the various causes of this phenomenon has been increasing. Aerosol optical depth (AOD) is an important remote sensing parameter that serves as a columnar proxy variable representing aerosol abundance. In this study, monthly mean AOD from Moderate Resolution Imaging Spectroradiometer (MODIS) are used to investigate the spatio-temporal distribution of dust storms in these affected areas for the period between 2000 and 2015. Monthly AOD data from the MOD08 Level 3 product (http://ladsweb.nascom.nasa.gov/data) at a resolution of 1° × 1° are used. This study focuses on AOD at 550 nm over land, as this is close to the peak of the solar spectrum and is, therefore, associated with major radiative effects. Synoptic data are examined to identify how well geopotential height, temperature, and wind field at various levels (i.e., sea level, /500/250 hPa isobaric levels) are related to AOD and to dust activity. Meteorological data from the ECMWF archived operational initialized analyses at a resolution of 2.5° × 2.5° (Bou Karam et al. 2010; http://apps.ecmwf.int/datasets/data/interim-full-moda/levtype=sfc) is used.
Results, MODIS monthly mean AOD validation results using the Pearson correlation test to determine the correlation between monthly mean AOD and monthly visibility data indicated high efficiency of AOD products in the dust storm intensity study. To distinguish between the Rub’ al Khali and the influence of factors such as dams in other areas, the study domain is divided in two sections consisting of desert areas in (i) Saudi Arabia and (ii) Iraq-Syria.
AOD plot of the provinces of the west and southwestern of Iran showed provinces of Khuzestan, Ilam, Kermanshah and Kohgiluyeh in order have experienced the highest dust storms from 2000 to 2015.
As the dust storms in all months of the year are not active, to evaluate the spatial distribution of mean AOD per year, the average for the months in which the dust storms are active evaluated (named as annual AOD). Annual and monthly average plots showed that the trend of the amount of AOD in many cases in the deserts of Iraq and Syria desert was similar to deserts of Saudi Arabia.
Considering the wide range of climatic conditions affecting the occurrence of dusty storms, the best way to find out the effect of circulation on the formation of dusty storms is to compare the synoptic state of a special month in two active and inactive periods. To achieve this goal, the monthly anomaly maps (monthly average of 30 years (1981-2010)) were extracted at surface level, 250 and 500 Hp. Two months as representative the active and passive dust storm period was selected to study atmospheric circulation associated with dust. To investigate the impact of synoptic systems on factors influencing dust in the study region, precipitation, temperature a case study analysis of July 2009 and July 2014 was conducted.
Also analysis the map of the average annual distribution of dust in each region shows that the trend of AOD value in many cases in the deserts of the Saudi Arabian desert was similar to Iraq and Syria desert, but AOD value in which years the dust in deserts of Iraq and Syria were still down is high in East and South East Arabian Peninsula. In this study, changes in the behavior of dust storms in the west and southwest of Iran were investigated using quantitative monthly and annual AOD data from 2000 to 2015. The result of the Pearson correlation test with the aim of determining the correlation between the monthly average visibility and mean monthly AOD and indicates the high ability of the AOD monthly data to study dust storms.
Trends of AOD show that from 2006 to 2012 there was increasing trend in February, March, April, May, June and July with a significant slope. The gradient of the monthly AOD slope of Kermanshah province was similar to Iraq and Syrian deserts and also Khuzestan province comply Saudi desert or desert of Iraq-Syria in different cases. These differences can only be caused by differences in atmospheric circulation in different dates.
By comparing the synoptic maps of active and passive anomaly, it seems at sea level pressure existence of Pakistan's low pressure center and increasing pressure on the Mediterranean Sea exacerbated atmospheric turbulence and wind speed in the Middle East play an important role on the intensification of dust storm activities. At the middle and upper levels of the atmosphere, the sovereignty of the subtropical high pressure over the Arabian Peninsula, south of Iraq, the Persian Gulf and the southern part of Iran, also increasing the activity of the Mediterranean waves, increasing the mean wind speed at the upper levels of the atmosphere, as well as the flow of jet stream core has led to an intensification of dust storms in July 2009. That's why limited dust storms have been created in central and eastern regions of the Arabian Peninsula

Today, the phenomenon of dust is known as one of the most important natural disasters in arid and semi-arid regions. The long-term effects of this phenomenon on the human health index are referred to as chronic disease. Therefore, studying and identifying the patterns and centers of this phenomenon seems necessary in these areas. In this study, in order to simulate the dust emission flux to determine the internal and external critical centers in the central plateau of Iran, WRF-Chem model and GOCART wind erosion scheme and storm were used from July 19 to 21, 2015. The results showed that the Arabian deserts in Saudi Arabia, the deserts of Iraq, as well as the Gharegham desert in Turkmenistan and the Helmand region in Afghanistan are among the most important foreign crisis centers affecting Iran's central plateau atmosphere. Also, the Central Desert (Dasht-e Kavir) has been identified as the main source of dust and the southern parts of the Central Loot Basin and the Jazmourian Basin have been identified as the internal sources of dust. The results also showed that in the Central Loot basin, the amount of 6900 micrograms per square meter of dust increases per second due to the erosion conditions.

One of the natural disasters which affects on Khuzestan province for its geographical location and its vicinity with large zones of desert areas is the undesirable phenomenon of dust. This research has been performed after extracting 50 recognized dust systems and dividing them in to two periods of cold and hot periods of the year during statistical period of (1996-2005) by using combined maps of geo potential height, elevation 500 Hecto Pascal, medium pressure of sea elevation, wind vector maps, isospeed lines and air flow at two levels of 500 Hecto pascal and medium level of the sea at range 0 up to 50 northern degree and 0 up to 70 eastern degree and satellite photos for two recognized dust systems.The results of this research shows that in the cold period of the year, migratory systems of westerlies (west winds) and polar front jet stream (PFJ) and in the hot period of the year, thermal low pressures of the earth surface are the main important factors in creation and formation of the said phenomenon in Khuzestan province. When deep pressure decrease occurs at the west part of the studied area in the deserts of neighboring countries and the wind speed reaches to jet stream wind, in case of availability of the environmental conditions, causes instability on the earth surface which produces dust and transfers it to Khuzestan province. Also In the hot periods of the year, thermal low pressures of the earth surface, especially Fars Gulf low pressure through sucking the air of surrounding deserts (Arabian Peninsula) is one the main factors of dust creation. Moving path of dust waves and manner of drop axis settlement and low pressure centers of the earth surface and also the used satellite photos show that the main sources of the entered dust in to Khuzestan province include southern desert of Iraq, North part of Arabian, south east of Syria and partly north of Africa desert.

The undesirable phenomenon of the dust storm is one of the natural disasters, which influences Ilam province due to its geographical location and adjacency to the large areas of desert. The study was performed after collecting 40 dust systems, and divided them into two cold and warm periods of the year, during the period 2000-2010, using geo-potential height maps of level 500, and sea level pressure, the wind vector maps, speed lines, and omega maps at 700 hPa level, ranging from 15 to 45 degrees North and 20 to 65 degrees East. In addition, to evaluate the situation in the upper atmosphere, by referring to the University of Wyoming weather database, Radiosonde data were received for days with dust storms in the Southwestern stations of Iran. Furthermore, by using software RAOB and SKEW-T diagrams, the data were drawn and analyzed daily. To study the stability and instability of the atmosphere, LI, SI, CAPE, and TT indices were used. Dust enhancement on MODIS images was performed using the features of the brightness temperature and Aerosol Optical Depth (AOD). The results indicated that during the cold era of the year, migratory systems of the west winds, and the along polar jet stream, and in the warm period of the year, the thermal low pressures of the earth surface are the most important factors in creating and shaping the phenomena of dust in Ilam province. When a deep landing occurs in the west part of the study area on the deserts of the adjacent countries, and the wind velocity reaches the jet stream speed, having the proper environmental conditions, by creating instability in the earth surface, they cause dust and its movement towards the province. During the warm era of the year, the thermal low pressures of the earth surface, and particularly low pressure of the Persian Gulf, by sucking the air of the surrounding desert (Arabian Peninsula) is an important cause of dust. The paths of dust waves, the deployment of the landing axis, the low pressure of the earth surface, and the used satellite images indicated that the most important sources of the entering dust to the province of Ilam are the Southern deserts of Iraq, northern deserts of Saudi Arabia, Southern deserts of Syria, and to some extend the Northern of the Sahara Desert.

Ce travail propose d’analyser la figure de Marga d’Andurain (1893-1948) à travers le concept d’anormalité développé par Michel Foucault. D’Andurain s’inscrit dans la lignée des femmes qui ont transgressé les normes sociales de leur époque en refusant de se cantonner à une vie domestique conventionnelle. Après avoir parcouru le Proche et le Moyen-Orient, le couple d’Andurain s’installe à Palmyre. Animée par un désir d’exploration, elle décide d’accomplir le pèlerinage de Hadj et de traverser le désert pour atteindre les rives du Golfe Persique. À cette fin, elle n’hésite pas à se convertir à l’islam et à contracter un mariage blanc avec un Najdien  Française et catholique mais aussi Najdienne et musulmane, elle ne cesse de défier les normes. L’analyse du Mari Passeport, récit autobiographique de son voyage en Arabie, met en lumière sa passion de la liberté, son esprit d’indépendance et son goût pour l’aventure. Figure atypique, elle pourrait incarner l’anormalité foucaldienne par son parcours de vie.

Introduction Yardangs due to intensive wind erosion are exclusive landforms on the earth's desert and possibly occur on Mars and Venus. The recent advances in the remote sensing technique and easily available of high resolution satellite data e.g. QuickBird provide useful information of remote area. Hence the mega-yardangs with tens meter high and hundred meters long are easily identifiable on satellite images and their global distribution and properties can be mapped. The Lut desert (Dasht-e Lut) in the south east of Iran is described as the “thermal pole of the Earth” (Mildrexler et al., 2006). With an area of about 80,000 square km it is regarded to the hottest and the driest desert in the world (Alavi Panah et al., 2007; Gabriel, 1938; Mildrexler et al., 2006). Yardangs are streamlined forms up to 150 km long and 75 m in height resulting from a number of formative processes, including wind abrasion, deflation, fluvial incision, desiccation cracks, slumping, weathering and mass movement (Goudie, 2007; McCauley et al., 1977; Ward and Greeley, 1984). A limited number of morphometric investigations have been done on yardangs. Goudie (2007) identified mega-yardangs in hyper-arid environments with total rainfall less than 50 mm including central Asia, the Lut desert in Iran, northern Saudi Arabia, Bahrain, the Libyan Desert in Egypt, the central Sahara, the Namib desert, the high Andes and Peruvian desert. According to Goudie, these features develop in a wide range of rock types e.g. sandstones, ignimbrites, limestones and basement rocks by a relatively unimodal wind direction. Materials and Methods In this study 3 arc second DEM of version 3.0 SRTM data (~ 90 m) with geographic projection acquired was used. That was re-projected to UTM grid with WGS84 Datum.We used 90 m DEM produced from version 3 SRTM 3 arc second data and the SOM algorithm for identification of yardangs in the western part of Lut desert. Self Organizing Map (SOM) is an unsupervised and nonparametric artificial neural network algorithm that clusters high dimensional input vectors into low dimensional (usually two dimensional) output map which preserve topology of the input data. In geomorphic studies of landscapes, the first and second order derivatives of DEM are the basic components for morphometric analysis (Evans, 1972). The second order derivatives of DEM are affected by geomorphological processes (Evans, 1972; Wood, 1996b). To calculate the morphometric features, a local window is passed over the SRTM DEM and the change in gradient of a central point in relation to its neighbors is derived by a bivariate quadratic function. Wood (1996a) defined a set of criteria to classify DEMs into morphometric classes. Yardang identification and analysis in the study area was performed using the parameters proposed by Wood (1996a). A local window of 5×5 is passed over the DEM and slope, cross- sectional curvature, maximum and minimum curvatures are derived by fitting a bivariate quadratic approximation surface. The derived morphometric parameters were used as an input to SOM. Frequency histograms and average quantization error of the results are compared. Two dimensional plots of mean values of morphometric parameters (feature space), oblique views of map units draped over the DEM, Landsat ETM+ data and high resolution QuickBird images were used to study the mega yardangs in other places than Iran. Results and Discussion Learning of the SOM was performed with four morphometric parameters as the inputs and a two-dimensional output of 10 neurons. The map with initial radius of 3, final neighborhood radius of 0.01 and 1000 iterations shows the best performance for yardang identification. The output map units from SOM are just numbers and need to be analyzed and interpreted. Studying the spatial relationship between different map units along with their morphometric parameters using feature space analysis allowed us to interpret and label them corresponding to morphometric features e.g. yardangs. Major morphometric features (corridor, planar and yardang) are identified in two-dimensional feature space plots of mean values of maximum curvature (x-axis) and minimum one (y-axis). The analysis of the results and corresponding satellite images shows the effectiveness of the method to identify the overall pattern of the morphometric features in the Lut desert. It is clear that the pattern of yardangs and their corridors running from NNW to SSE direction is parallel to the prevailing wind known as “wind of 120 days or Bad-i-sad-o-bist rooz-e Systan. Conclusion The results show that digital terrain analysis methods applied on SRTM in the proposed way in this study could extract morphotectonic features from SRTM along Dehshir fault and they contributed to the tectonic interpretation of the study area. According to the evidences extracted from SRTM along Dehshir fault, for example: fault traces, deflected and beheaded drainages, pattern of network drainages, erosion surfaces of uplifted and back erosion of drainages because of the location (situated in quaternary landforms), they are neotectonic evidences for activity of Dehshir fault during quaternary. Our results reveal that the morphometric analysis and feature space analysis of the first and second order derivatives of DEM such as slope, cross-sectional curvature, maximum curvature and minimum curvature led to the description of SOM outputs as yardangs, corridors and planar. Slope allows distinguishing among morphometric features in sub levels. The optimal self organizing map with suitable learning parameters should be selected for feature identification. The lowest average quantization error of 0.1040 was achieved with an initial radius of 3, a final neighborhood radius of 0.01 and 1000 iterations. Result of this method revealed that from the total 6481 km2 coverage of the study area, about 2035 km2 (34%) are classified as yardang while corridors, in total cover 2732 km2 (43%).

Which parts of Arabian Peninsula were under the Achaemenids’ control? and how did they administer those regions? Researchers have widely different viewpoints on the answers to these questions. The present paper is an attempt to clarify the political and administrative policy of the Achaemenids regarding this land, through reviewing previous research, and according to new historical and archaeological evidence. This study indicates that a large part of the peninsula was unknown and out of reach at that time. So, it cannot be considered as an integrated geographical and political unit. It seems that, Arabia, administratively and politically, was divided into separate parts: the satrapy of Arabāya from southern Syria and the Negev desert to the northern Hijaz; and some areas along the southern coasts of the Persian Gulf, such as Bahrain (Tiliman/Dilmun) and Oman (Maka), were also considered as separate political units. The Achaemenids’ administrative system managed the southern coasts of the Persian Gulf through the satrapies of Babylon and Makran (14th Satrapy), and they had under control the transit areas of northern and western Arabia through an alliance with the Qedarite Confederation. The expansion of qanats and the revenues from the incense trade show that there has been a mutually beneficial relationship between the two sides.

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

Air pollution is now a major problem in Tehran's metropolis, which threatens the health of its citizens more than anything else. The purpose of this study was to introduce frequent and common synoptic patterns in the incidence of severe and critical pollution in Tehran. For this purpose, air pollution data were first obtained from Tehran Air Quality Control Bureau (2007-2017) and then hazardous days were identified based on AQI index at each of the stations. The rest of the NCEP / NCAR database reassessment data was obtained with a spatial resolution of 2.5 at 2.5 ° for sea level, 1000, 925,850 and 700 hp. After delineating a synoptic map of the above alignments, multiple dominant and repetitive synoptic patterns have been identified and analyzed by repeated eye examinations. During the statistical period, 157 days of severe and dangerous contamination were identified. Among the pollutants affecting Tehran, the most pollutants are PM10, PM2/5 and NO2. An in-depth examination of 5 synoptic patterns revealed severe contamination: Patterns of European immigrant high-pressure, Siberian high-pressure, mixture of Siberia and Saudi high pressure, and Pakistani low pressure. In a pattern commonly occurring during warm-weather pollutions, low-pressure Pakistan played the most important role in producing severe winds in the deserts surrounding Tehran, with the most pollutants being PM10 and PM2.5. The second pattern is caused by the cold season pollutions. In the model, the Siberian high pressure in the lower tropospheric layer (below 850 hPa) with cold advection was the main cause of stability and accumulation of pollutants and at higher levels of the Arabian high pressure stack, while intensifying stability and persistence of atmospheric conditions. In this model, cold-weather stability dominates the city of Tehran. In the third dominant pattern of high pressure Saudi Arabia and its tablets in all atmospheric layers cause very strong stability and persistence of pollution and air stability. In this model, due to the dynamic nature of the system, despite the stability, the air temperature gradually increases and conditions are quite different from the seasonal conditions.

The severe and widespread dust on March 12-18, 2021 over a large part of Asia investigated. Satellite data, synoptic maps, and the HYSPLIT diffusion model and the WRF-Chem model outputs have used. On March 12, the dust particles transfered from Iraq to Iran and the dust emission started from the deserts of Arabia; and the dust particles were transferred to the countries of Afghanistan, Pakistan and China. In addition to long-range transport, the dust emission from local sources in the border areas of Afghanistan, Pakistan, Iran as well as the central of Turkmenistan and the western/central of China increased the intensity of the phenomenon and the extent of the areas affected by dust. In the synoptic analysis, a series of low-pressure systems observed in the south of Arabia, south/southeast Iran, Kyrgyzstan and China, which caused the dust emission and transport in the area. CALIPSO products show that in a large part of the region, there are suspended dust particles, and clouds are mostly deep convective and cirrus. The WRF-Chem model correctly simulates the dust emission from Iraq, Syria and Saudi Arabia and its transfer path. The activity of dust sources around Lake Hamon, Turkmenistan and central China can be seen in the output of the model. The vertical cross-section of dust concentration and quantities of relative humidity, wind speed and potential temperature indicate the penetration of dust particles to the upper levels of the atmosphere, which is the reason for their long-range transport under the influence of higher wind speed.