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Soil moisture content is one of the critical parameters in water resource studies and watershed management. Large-scale field measurement is a tough, time-consuming, and costly task. newly, models based on remote sensing indicators have found special importance with high accuracy to investigate the soil and water resources. This study aims to use Landsat 8 satellite imagery to study variation in topsoil moisture content of dust hotspots of southeastern Ahvaz of Iran, over the five months (from February to June 2019). After monthly field sampling, satellite images were applied to determine the NDMI index and the topsoil moisture content using Bands 5 and 6 (main Bands) of Landsat 8 satellites. Then, by fusion, with Band 8 (panchromatic Band), the soil moisture content map was obtained for each month. The Pearson correlation positive was obtained between the NDMI of the main band and the NDMI of fusion with the soil moisture content of field for April month, with a correlation coefficient 0.543, and a significance level of 0.05 (P-value < 0.05). Also, for each month, the humidity index modeling was obtained for both data (the main (original) band and the fusion band). The proposed model was evaluated using statistical metrics namely R2, RMSE and MAE to April month, and the results were 0.57, 1.25 and 5.45, respectively. After validating the models, the best ones were selected for estimating the soil moisture content. Finally, the obtained results showed that Landsat 8 data presented satisfying outcomes for estimating map soil moisture content. [ABSTRACT FROM AUTHOR]

The dust storm on the surface of Mars is a severe threat to Mars exploration missions. Taking adequate measures to avoid the impact of the harsh wind-blown dust environment is indispensable. Ground simulation of the Martian high-speed windblown dust environment is helpful for analysis of the environmental effects and evaluations of the suitability of the components and materials. In this paper, a novel reflux subsonic low-density dust wind tunnel is presented to simulate the high-speed windblown dust environment of the Martian atmosphere with a velocity of more than 100 m/s. The sand and dust are fed into the wind tunnel through the ejector assembly together with the compressed gas, resulting in high uniformity of particles in the test section. The construction design of the Mars wind tunnel is introduced. The key parameters, which are the nozzle parameters and the contraction curve, are discussed in detail. The convergent nozzle is most suitable for the ejector assembly. Moreover, the bicubic curve is selected as the contraction curve. The gas-particle two-phase computational fluid dynamic (CFD) simulations demonstrate the rationality of the wind tunnel design. [ABSTRACT FROM AUTHOR]

Data dealing with polycyclic aromatic hydrocarbons (PAHs) levels in settled dust of Greater Cairo houses (GCH), Egypt, and their implication on human health risk are scarce. The goal of this study was to gain insights into the characterisations of PAHs in settled dust in GCH and their associated carcinogenic and mutagenic risks. ƩPAH concentrations were 3125 and 268 ng/g in settled dust in GCH and rural houses (RH), respectively. Heavier congeners (4–6 aromatic ring PAHs) represented 86.5% (GCH) and 92% (RH) of ƩPAHs. Houses on main streets are exposed to higher levels of PAHs than those on the side streets. The main sources of PAHs in GCH and RH were vehicular emissions (pyrogenic sources) and PAHs in GCH come from local emissions and in RH from the surrounding urban cities. Results showed that the carcinogenicity of PAHs associated with dust exceeds their mutagenicity. Based on Incremental Lifetime Cancer Risk (ILCR) estimations, the order of cancer risk (CR) was as follows: urban houses (UH) > suburban houses (SUH) > RH. CR and ILCRs calculations suggest that children and adults exposed to settled dust-bound PAHs in GCH and RH have an increase in CR, as CR and ILCRs values exceeded accepted levels. [ABSTRACT FROM AUTHOR]

The Emirates Mars Mission (EMM) science phase began in Martian Year 36, solar longitude 49, which is outside of the classical Mars dust storm season. EMM observed a distinct dust cloud at northern mid‐to‐high latitudes on 10 September 2021 (Martian Year 36, solar longitude 97). The dust cloud is an arc‐shaped dust storm, typically observed at the northern polar cap edge. This type of non‐season dust storm is a well‐known phenomenon, but this particular case is interesting because the dust cloud has frontal structure. A large atmospheric front is unusual in this location and season. Moreover, EMM's unique observational coverage adds value to this observation. EMM provided a sequence of four camera images, which are separated by just 2–3 hr. The dust cloud showed very little motion over 7–8 hr, that is, it is quasi‐stationary. We discuss relevant dynamical processes, supported by a consistency check with the Mars Climate Database. Plain Language Summary: The Emirates Mars Mission (EMM) officially started its science observations on 23 May 2021. We saw some, but not many dust storms until end of 2021. That is because Mars has a dust storm season and a non‐dust‐storm‐season, and EMM arrived during the latter. On 10 September 2021, EMM observed an arc‐shaped dust storm close to the northern polar cap. This type of non‐season dust storm is well‐known. What makes this observation interesting is that the dust storm is also a weather front. A large atmospheric front is unusual for this location and time during the Martian year. Moreover, it is unique how EMM observed this dust storm. EMM took a camera image every 2–3 hr, giving four dust cloud images in total. The dust cloud showed very little motion over 7–8 hr. We discuss how the motion of air masses in the Mars atmosphere may have caused the observed dust storm. The discussion is supported by wind and temperature data from the Mars Climate Database. Key Points: We study a sequence of four Emirates Mars Mission images, showing a frontal dust cloud on 10 September 2021 (solar longitude 97)The dust cloud extends from the Chasma Boreale of the northern polar cap to the midlatitudes; it shows very little movement for 7–8 hrLarge atmospheric fronts are unusual in this location and season; we discuss dynamical processes, supported by the Mars Climate Database [ABSTRACT FROM AUTHOR]

The patterns and forcing mechanism of dust storms in arid Northwest China remain unclear and debated due to lack of reliable long‐term geological records. Here we present a ∼1,600‐year dust storm history in Northwest China based on the sedimentary coarse fraction (>63 μm) retrieved from Lake Hurleg and Lake Qinghai on the northeastern Tibetan Plateau (NETP). The NETP dust storm history, which agrees well with those from North China, shows two prolonged intervals of high dust storm occurrences during the Medieval Warm Period and the past century, and two prolonged weakened dust storm intervals from ∼400 to 700 CE and during the Little Ice Age. The temporal variation in NETP dust storm activities is out‐of‐phase with moisture records over central Asia, with enhanced dust storms corresponding to warm‐dry intervals, and vice versa. The prolonged centennial warm‐dry climates over arid Northwest China to arid central Asia could have led to decreased soil moisture, deteriorated vegetation cover, and increased dust particle supply and dust storm activities; while the prolonged centennial cold‐wet climates could have increased soil moisture, vegetation cover, and decreased dust storm activities. We contend that whilst human impact could be responsible for the obviously increased eolian dust flux in the most recent century, it is most likely that the prolonged natural hydroclimatic conditions regulate the global dust storm activity before the Anthropocene. Key Points: A ∼1,600‐year dust storm history over Northwest China was reconstructed based on sedimentary grainsize from Lake Hurleg and Lake QinghaiProlonged drought dominates dust storm occurrence by decreasing vegetation cover and increasing dust‐particle supply on centennial timescaleNatural climate variability rather than human activity could have shaped the Northwest China dust storm activities before the Anthropocene [ABSTRACT FROM AUTHOR]

This study investigates the mesoscale dynamics involved in the 8–11 October 2008 unseasonably strong African dust episode, during which dust was transported to the Iberian Peninsula (IP). We employ observational datasets and a high‐resolution Weather Research and Forecasting model coupled with Chemistry simulations. The analysis shows that during 0900–1200 UTC 9 October, a mesoscale convective system developed over the Atlas Mountains and resulted in a southwestward propagating convective cold pool outflow on the southern foothills of the Anti‐Atlas, which lifted dust from the source region. Between 1200 and 1800 UTC 9 October, new moist convection was enhanced over the Atlas Mountains due to intensifying confluence among a heat low, moist southwesterly Atlantic sea‐breeze front, and northeasterly flow associated with the convective cold pool near western Algeria. This new moist convection intensified the strength of the convective cold pool outflow and haboob, both of which continued propagating southwestward. At 1200 UTC 10 October, the low‐pressure system migrated poleward on the southern slopes of the Anti‐Atlas Mountains in association with a mountain‐plains solenoidal circulation due to the daytime differential heating between the southern slopes of the Anti‐Atlas and nearby atmosphere. The deepening low‐pressure and strengthening Atlantic sea‐breeze redirected an equatorward advancing dust plume into the poleward direction. The dust plume ultimately crossed the Saharan Atlas Mountains on 11 October and finally impacted the IP. Key Points: WRF‐Chem simulation of an unseasonably strong haboob on the southern slopes of the Atlas MountainsThe equatorward‐advancing dust plume was recirculated in the poleward direction by an Atlantic sea‐breeze frontThe Atlantic sea‐breeze front and an intensified upper‐level cutoff vortex are instrumental for dust transport over the Iberian Peninsula [ABSTRACT FROM AUTHOR]

Dust storms are frequent in the Sistan region of south-eastern Iran and cause a wide range of problems, but few studies have assessed their negative impacts. This paper makes an assessment of the impacts and estimates the damage costs associated with dust storms on transportation systems—aviation, road and rail—over the period 2013–2020. Daily visibility data were used to obtain the number of dust-storm days, and information on the damage to each transportation sector was collected from the relevant local authorities. A strong relationship was observed between dust storms and the number of flight cancellations and car accidents and the amount of accumulated sediment on the roads, by month and year. The impacts were greatest during summer months (June–August) and in 2018, the year of highest dust storm frequency. The total estimated cost to the three transport systems was US$46.5 million over the 8 years studied, with most of the costs (66%) associated with road transport. The results provide managers with a basis from which plans can be developed to control and mitigate the impacts of dust storms. [ABSTRACT FROM AUTHOR]

Awareness of the possible velocity and load of dust particles carried by the wind could be beneficial for preventive measures and preparation for health, transportation, military, and other damages of this atmospheric phenomenon. Aerosol optical depth (AOD) is closely related to visibility (V), and both of these parameters are so important and useful to studies connected to aerosols, tropospheric dust, air pollution, and atmospheric radiation budget. This research analyzed the mathematical relation between the aforementioned parameters and wind speed (WS) as a key index in storms by using evolutional genetic algorithm (GA). The study area is Yazd Province as representative of central Iran for 20 years (2000–2019). In fact, the purpose of this analysis has been to reach a relation that can estimate unavailable quantities of mentioned data parameters based on the available data of other existing parameters with the least error. To attain this mathematic equation, the linear regression and several other well-known functions have been compared. Meanwhile, the binomial function was selected as the best fitness function. The result was a mathematical equation between AOD parameters, visibility, and wind speed during the occurrence of 30–35 synoptic codes based on a binomial function with the confidence level of 95% was as follows: WS = 19.115 − 0/0033 × V + 1.2 × AOD. The equation presented in this research is an experimental equation that is presented for the first time and has the ability to be used and to calculate the mentioned parameters throughout central Iran and areas similar to the environmental conditions of central Iran. [ABSTRACT FROM AUTHOR]

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A dust storm is one of the costliest and most destructive events in many desert regions. This research investigates the effect of dust storm on sea surface temperature (SST) in the western zone of the Persian Gulf, especially Bushehr Province and its beaches in the years 2008 and 2009. Therefore, some climate and sea parameters such as SST, salinity, air temperature, wind velocity and direction, evaporation, horizontal visibility, sunshine hours and radiation, simultaneously measured in a specific period of time, were analyzed by comparing each of them with satellite data. Sea surface temperature analysis in summer shows that the maximum SST in Persian Gulf along neighbor waters to Bushehr County and central regions in northern section of Persian Gulf is about 34–36 °C. The SST amplitude variation in these places in summer ranges from 28 to 34 °C and when there are dust phenomena, it is from 29.5 to 31 °C. The outcome of this study shows that the SST increases during dusting phenomena and this causes an increase in vapor and as a result a decrease in temperature occurs. On the other hand, vapor increase leads to a growth in the amount and layer of earth's cloud cover and finally it causes an effective decrease in short-wave sunshine and the temperature and the vapor on surface decrease. As a result, the decrease in sea surface temperature terminates. [ABSTRACT FROM AUTHOR]

Mars shares many similarities with Earth. The comparative study of the climate between the two planets is of great significance to understand the evolution of the Earth's atmosphere. On the other hand, Mars is a desert planet with plenty of dust particles both on the ground and in the atmosphere. The dust cycle including the dust storm is an extremely important component of the climate system to Mars. Based on previous researches on the Martian dust storms and atmospheric waves, we summarized the temporal and spatial scales and the seasonal evolution of Martian dust storms. We introduced the characteristics of the Martian atmospheric tides and planetary waves and their responses to dust storms. The dynamical effect of the atmospheric waves on the transport and evolution of dust storms and the spatial distribution of the airborne dust is also significant. More future studies are needed to understand the coupling process between dust storms and atmospheric waves.

Dust storms frequently occur in the spring over East Asia, affecting southern Mongolia and northeast China. An exceptionally powerful dust storm occurred in East Asia from March 14th to March 18th, 2021. To investigate the ability of climate models to simulate severe dust storms, we employed the Weather Research Forecast model coupled with chemistry (WRF-Chem) with Goddard Chemistry Aerosol Radiation and Transport (GOCART), SHAO and KOK dust emission schemes to simulate the evolution of this event and to characterize dust aerosols long-range transport. Results showed that this storm was caused by a Mongolian cyclone depicted at 850 hPa with a cold front, which swept dust aerosols southeastward across southern Mongolia to northeast China. Model evaluation with satellite-retrieved Aerosol Optical Depth (AOD) and observational PM10 concentrations revealed that the SHAO dust emission scheme performed better in simulating spatial and temporal distribution of AOD over the Gobi Desert (GD) but overestimated them over Taklimakan Desert (TD). In contrast, the GOCART dust emission scheme underestimated AOD over most areas except the Taklimakan Desert; the KOK dust emission scheme overestimated them over both TD and GD. Overall, the SHAO dust emission scheme had good performance in simulating the surface PM10 concentrations over the Yangtze River Basin (YRB) and depicted an increase in PM 10 concentrations, which denoted the transport of dust aerosols over YRB. As a better description of the physical process of dust emission flux over the eastern region of the Gobi Desert, the SHAO dust emission scheme depicted well the spatial and temporal evolution of dust plume episodes, especially over northeast China and YRB. The significant differences in dust emission fluxes between the three dust emission schemes were attributed to the sensitivity of threshold friction velocity and erodibility factor. Thereunto, the SHAO dust emission scheme incorporated well soil particle size distribution and threshold velocity to produce the dust emission flux, which allowed higher dust emission flux over the eastern GD and under strong southwesterly transported dust aerosols to East Central China's region of North China Plain (NCP) and YRB. This study will help further the simulation of extreme dust events more accurately and the exploration of climate change's effect on dust events over East Asia. • The Yangtze River Basin region is affected more by GD dust aerosols than TD dust aerosols. • SHAO dust emission scheme performed better in simulating dust storm from Gobi Desert. • Dust particles are mainly suspended in thte lower and middle troposphere over dust source areas. [ABSTRACT FROM AUTHOR]

The possibility of suspending radioactive particles during dust storms from Iraq and entering Iran has always been a concern. The aim of this study was to investigate the particulate matter concentration during dusty days and the effect of dust storm on the irradiation rate in the atmosphere of the city of Ilam (capital of Ilam province). The concentration of particulate matter and radiation dose in the study area were monitored between March 2012 and February 2013 (1 year). Sampling was done every 6 days for periodical days. For the dusty days, samples were gathered according to the forecast information of dust plum entrance by the meteorological organisation. The results showed that the average and standard deviation of PM10, PM2.5, and PM1 concentrations in the periodic sampling (every 6 days) were 76.9 ± 57.1, 17.5 ± 10.5, and 8 ± 4 μg/m3, respectively, and in the dusty days were286 ± 164.8, 54.4 ± 30.3, and 14.6 ± 6.5 μg/m3, respectively. During the study period, the concentration of PM10in 35 days were more than 150 μg/m3 (Dusty day), and June with 13 days was the highest number dusty days. The average radiation dose in normal and dusty days were 0.152 and 0.150 μSv/hr, respectively. The results of Mann–Whitney's test showed that there was no significant difference between measured radiation in normal and dusty days (P > 0.05). Spearman test showed that there was no significant correlation between radiation doses and PM (PM10, PM2.5, and PM1) (P > 0.05). The results of the study show that dust storms and its concentration intensity did not affect the amount of radiation in the Ilam atmosphere. Because of the high density of the uranium element and its rapid sedimentation near the emission sources, the entry of this contamination related to dust storms to Ilam has not been proven. [ABSTRACT FROM AUTHOR]

On 15 March 2021, the strongest sandstorm of the last 10 years occurred in China. The MODIS, MPL lidar, EDM 180, ADI 2080 and Meteorological observation instruments were used to observe the dust in Jinan, China, while the HYSPLIT model was also employed to find the source. It was found that the dust originated from Mongolia and the Gobi desert and was transported to Jinan at night on 14th March, lasting until the 18th. Multi-layer dust was observed, of which the dust below the height of 1 km was strongest with the VDR about 0.2 and the maximum extinction coefficient up to 3 km−1. The values of AOD and AE were greater than 2 and less than 0.25, respectively. The mass concentrations of PM10 and PM2.5 increased rapidly, and were up to 573 µg/m3 and 3406 µg/m3, respectively. Additionally, the mass concentration ratio decreased rapidly, with a minimum of 17%. The particle size of the dust was mainly distributed between 0.58–6.50 micros due to larger particles increasing dramatically; simultaneously, both the proportion and the value for calcium ions in PM2.5 went up. The dust had an obvious impact on the vertical structure of the air temperature, resulting in occurrence of a strong inversion layer. [ABSTRACT FROM AUTHOR]

The present study focuses on investigating the impacts of a sudden dust storm on the atmospheric boundary layer (ABL) over Ahmedabad (23.02°N, 72.57°E), an urban site located in the western region of India. The accumulation of dust particles in the atmosphere during the dust storm, originating from the Thar Desert in Rajasthan, led to the decrease in surface temperature as a consequence of dust–radiation interaction. Ambient particulate matter data obtained from Air Quality (AQ) station at Ahmedabad showed a spike of 118.5% and 44.5% in PM10 and PM2.5 concentrations, respectively, during the event in comparison with the previous control day. Sudden exposure to an anomalous increase in the particulate matter may cause severe impacts on human health. These surface forcings have been reflected in the stable nocturnal ABL. Backscatter signals recorded by ground-based Ceilometer Lidar at Physical Research Laboratory (PRL) showed that ABL was shallow and collapsed during the dust storm episode. Turbulence has been detected in the ABL during the event which further assisted in the vertical mixing of dust particles in the ABL. These dust particles got trapped within the residual layer, preventing further percolation in the free atmosphere. Such sub-grid scale changes in the ABL during the dust storm were not reflected in the boundary layer height (BLH) obtained from the ERA-5 reanalysis dataset. A significant association between the ABL and the local radiative budget has been found. Coupled Ocean–Atmosphere Radiative Transfer Model (COART) simulations substantiated or showed a cooling event of the surface during the dust storm. This study is important as it can be taken as feedback to improve local climate models with respect to dust storm meteorology. [ABSTRACT FROM AUTHOR]

Spring gale is a dynamic power for DSs (DSs), which presents a close connection with the DSs of northern China. Both display declining trends during the past 68 years (1954–2021). In this study, the influencing factors of spring gales and DSs around northern China and possible adjustment functions of the East Atlantic (EA) teleconnection pattern have been investigated. It was found that the major systems controlling spring gales include the North Polar vortex (NPV), mid–high‐latitude blocking highs (BHs), air pressure status of the Tibetan Plateau (TP) over the Eurasian continent, India–Burma trough (IBT) and western Pacific subtropical high (WPSH). Under synthetic atmospheric circulation conditions of an enlarged NPV, lower air pressure over the TP, a strong IBT, and a southeastward‐retreated WPSH, spring gales increase, and the frequency of DS occurrence is increased, and vice versa. Additionally, spring gales are also negatively affected by BHs. The most important is the Baikal BH, which has influence not only in previous seasons but also in the contemporary spring. Furthermore, the NPV and IBT have close negative correlation with the EA pattern, whereas the TP and WPSH have positive correlation with the EA pattern both in previous seasons and in the contemporary spring. A high‐pitched EA pattern results in a strong western current north of Lake Baikal, which may prohibit the expansion of the NPV in the sector of northern China. A shrunk NPV means infrequent cold air attacks and decreased gales and DSs. [ABSTRACT FROM AUTHOR]

Motivated by the lack of research on land cover and dust activity in the Middle East, this study seeks to increase the understanding of the sensitivity of dust centers to climatic and surface conditions in this specific region. In this regard, we explore vegetation cover and dust emission interactions using 16-day long-term Normalized Difference Vegetation Index (NDVI) data and daily Aerosol Optical Depth (AOD) data from Moderate Resolution Imaging Spectroradiometer (MODIS) and conduct spatiotemporal and statistical analyses. Eight major dust hotspots were identified based on long-term AOD data (2000–2019). Despite the relatively uniform climate conditions prevailing throughout the region during the study period, there is considerable spatial variability in interannual relationships between AOD and NDVI. Three subsets of periods (2000–2006, 2007–2013, 2014–2019) were examined to assess periodic spatiotemporal changes. In the second period (2007–2013), AOD increased significantly (6% to 32%) across the studied hotspots, simultaneously with a decrease in NDVI (−0.9% to −14.3%) except in Yemen−Oman. Interannual changes over 20 years showed a strong relationship between reduced vegetation cover and increased dust intensity. The correlation between NDVI and AOD (−0.63) for the cumulative region confirms the significant effect of vegetation canopy on annual dust fluctuations. According to the results, changes in vegetation cover have an essential role in dust storm fluctuations. Therefore, this factor must be regarded along with wind speed and other climate factors in Middle East dust hotspots related to research and management efforts. [ABSTRACT FROM AUTHOR]

Quantitative identification of a dust storm weather is key to forecasting and early warning of dust storm disasters. However, traditional visibility ground-based measurements cannot be extended to regional observations. Remote sensing of dust storms is associated with large uncertainties in dust thresholds. For accurate quantification of the dust storm region, this study proposes a dust storm mask algorithm to identify dust storm in the Tarim Basin. The dust storm mask includes two algorithms to identify the dust storm outbreak and the spatial extent by using the Advanced Geostationary Radiation Imager (AGRI) on board the FY-4A satellite. A deep learning convolutional neural network (CNN) is employed for the dust storm mask, and the AGRI bands 1–3, 5–6, and 11–13 are used as model parameters. A physical algorithm (PA) is adopted to construct a dust storm mask using three physical dust indices: the Normalized Difference Dust Index ( N D D I 2.25 μ m - 0.47 μ m / 2.25 μ m + 0.47 μ m ), the Dust Ratio Index ( D R I 7.10 μ m / 3.75 μ m ), and the Brightness Temperature Difference ( B T D 3.75 μ m - 13.50 μ m ). The results show that the CNN algorithm has a higher classification accuracy on dust storm detection compared to the PA. This advantage suggests that the CNN can effectively monitor large-scale dust storms. The dust storm identification results were compared and analyzed with the AGRI true color, Aerosol Optical Depth products, and Ultra Violet Aerosol Index products. [ABSTRACT FROM AUTHOR]

In this publication we demonstrate how interdependent are our geophysical shells. The large-scale air pollution provided by the intensive volcano eruptions and dust storms from desert areas modify the electric properties of the troposphere creating the low conducting layers and increasing the column resistance for the vertical current flowing between the ionosphere and ground within the Global Electric Circuit (GEC). This modification leads to the local modulation of the ionospheric potential (IP) magnitude and hence to formation of the large-scale irregularities of electron concentration in the ionosphere. To reveal these phenomena, we use the differential GIM TEC mapping procedure showing specific features of the ionosphere reaction. In low latitude and equatorial regions we observe the formation of positive TEC anomalies not only over the area of air pollution but in the magnetically conjugated area as well. We can conclude that these phenomena pose the double error for Precise Point Positioning (PPP). To the danger of aircraft engines destroying is added the increase of navigational PPP errors due to sharp TEC gradients on the borders of the formed large-scale positive irregularities of electron concentration. [ABSTRACT FROM AUTHOR]

The monitoring and tracking of urban air pollution is a challenging environmental issue. The approach of synchronous 3-D detection of wind and pollution using a solo coherent Doppler wind lidar (CDWL) is developed and demonstrated. The 3-D distribution of pollutant is depicted by the backscatter coefficient based on signal intensity of CDWL. Then, a high-resolution wind field is derived to track the local air pollution source with its diffusion and to analyze transboundary air pollution episodes. The approach is experimentally implemented in a chemical industry park. Smoke plumes caused by point source pollutions are captured well using plan position indicator (PPI) scanning with low elevation. A typical source of pollution is located, combining the trajectory of the smoke plume and the horizontal wind vector. In addition, transboundary air pollution caused by the transport of dust storms is detected in a vertical profile scanning pattern, which is consistent with the results of national monitoring stations and backward trajectory models. Our present work provides a significant 3-D detection approach to air pollution monitoring with its sources, paths, and heights by using a solo-CDWL system. [ABSTRACT FROM AUTHOR]

Dust storm (DS) represent global air pollution and health issues considering the high morbidity and premature death rate every year. This study explores the characteristics, composition, and variations in inhalable particulate matters (PMs) as well as their corresponding in vitro toxicity to human lung epithelial cells (A549) during DS and normal days (ND) in the downtown (DT) and the north suburban (NS) of Nanjing city, eastern China. Results showed that compared to ND, concentrations of heavy metals (i.e., Cr, Cu, Ni, and Pb) bound in PMs were lower during the DS. Furthermore, the relationship of cytotoxicity with Ni and Pb levels in PMs was significant. However, the cytotoxicity difference was insignificant between NS and DT. This may be due to the long-range transport of components from natural sources mixed with local pollutants emitted from anthropogenic sources, offsetting the pollution difference between urban and suburban areas. During both periods, PM 2.5 toxicity was greater than PM 10 , while the potential of PM 10 to induce proinflammatory cytokines was comparable to PM 2.5. Results suggested that inflammation risk will increase significantly during DS due to a substantial increase in ambient air PM 10 concentration. [Display omitted] [ABSTRACT FROM AUTHOR]

The East Asian dust storms occur in western and northern China, and southern Mongolia every year, particularly in spring. In this study, we use satellite aerosol products to demonstrate the spatial and temporal variation in aerosol optical depth (AOD) from MODIS, and the absorbing aerosol index (AAI) from TOMS and OMI, over the main dust storm source regions (MDSR), and to investigate their relationship to vegetation coverage (NDVI), soil properties (surface soil moisture content and soil temperature 0–10 cm underground), and climatic factors (surface wind speed, air temperature at 2 m above the ground, and precipitation) in spring for the period of 2000–2021. Compared with dust storm occurrence frequency (DSF) observed at surface stations, MODIS AOD, TOMS AAI, and OMI AAI showed consistent spatial distributions and seasonal variations with DSF in the MDSR, with correlation coefficients of 0.88, 0.55, and 0.88, respectively. The results showed that AOD and AAI over the MDSR decreased during 2000–2005, 2006–2017, and 2000–2021, but increased during 2017–2021.The improvements in vegetation coverage and soil moisture together with favorable climatic factors (the increase in temperature and precipitation and the decrease in surface wind speed) resulted in the decreasing trend of AOD and AAI during 2000–2005, 2006–2017, and the entire period of 2000–2021. Conversely, the increase in surface wind speed, the decrease in temperature and the low soil moisture in 2018 and 2020 were the reasons for the increases in AOD and AAI over the MDSR during 2017–2021. The combination effects of surface wind, temperature, soil moisture, and vegetation coverage would determine DSF, AOD, and AAI, in the end, under global climate change. [ABSTRACT FROM AUTHOR]

The wildfires across the eastern states of Australia during 2019 were responsible for devastating loss of life and property along with untold environmental damage. In New Zealand while our primary research focus is investigating the composition and contribution of sources to local and regional particulate matter concentrations, occasionally transboundary events such as the the Australian wild fires are captured inadvertently in ambient sampling. With a specific focus on the events spread across several months at the end of 2019 and the beginning of 2020, we present the forensic evidence of how long-range transport of dust-storm and wild-fire events from Australia can impact air quality at concentrations sufficient to exceed the New Zealand PM10 National Environmental Standards for Air Quality (50 µg m-3 as a 24-hour average). By using a combination of particulate matter size-fraction and compositional analysis coupled with meteorological data and air mass back-trajectories we describe the source(s) primarily responsible for the elevated PM10 concentrations observed at NZ urban monitoring sites. [ABSTRACT FROM AUTHOR]

Recurrent dust storms represent a significant concern in Australia because of their related hazards and damages since particulate matter (PM) has harmful impacts on the environmental, health and economic sectors. The particulate matter may be released from natural sources and human activities. The major part of natural particulate matter is emitted into the air by wind erosion processes from desert and semi-desert areas at the world scale. A huge dust storm crossed over several areas of New South Wales (NSW), Australia, including the Sydney region on 21–22 November 2018 and decreased the horizontal visibility to less than 1 km for 22 h. This study examined the synoptic weather conditions, and assessed the air quality and identified the source and transport trajectory of the dust storm over Sydney using ground and satellite remote sensing data. PM10 (< 10 μm) concentrations were obtained from selected air quality monitoring sites operated by the Environmental Protection Agency in NSW. The highest hourly concentration of PM10 (578.7 μg/m3) was recorded at Singleton in the Hunter Valley, while concentrations in Sydney ranged from 480 to 385 μg/m3, well above the standard air quality level in Australia (50 μg/m3 per 24 h). The HYSPLIT back trajectories of air parcels suggest that the potential sources of the dust episode originated from the Lake Eyre Basin and northeast South Australia, the Mundi Mundi plains west of Broken Hill, Cobar and the grazing lands and the red sandplains in northwestern NSW. It then travelled towards the east coast. These long-range airflows transported suspended dust particles, raising air quality to hazardous levels (elevated PM10 levels) over most areas of NSW. The results from the HYSPLIT model for dust movement are confirmed by MODIS satellite images. Many areas of NSW experienced this intense dust storm due to northwest wind generated by the low-pressure systems and cold fronts over South Australia and many parts of western NSW as it moved eastward. [ABSTRACT FROM AUTHOR]

In this study, we characterize the meteorological conditions and planetary boundary layer dynamics in western United Arab Emirates based on 2012–2020 in-situ measurements. This multi-year analysis is then complemented by an intensive field-campaign in winter 2021 from which we address the main patterns of the atmospheric circulation and the boundary layer structure during typical weather events identified in the long-term analysis. We found that, 10-m and 60-m wind speeds are generally below 5 m s−1 and 8 m s−1, respectively, blowing predominantly from a northerly direction. They peak in intensity at around 12–18 Local Time (LT) and 02–09 LT in association with the sea-breeze and the downward mixing of momentum from the nighttime low-level jet, respectively. The wind is stronger in the cold season, varying mostly in response to mid-latitude baroclinic systems, while the proximity of the site to the core of the Arabian Heat Low leads to more quiescent conditions in the summer. Radiation fog is a regular occurrence mostly from December to February owing to the colder nights and weaker wind speeds, with a peak fog occurrence around local sunrise. Sea fog, which develops when the hotter desert air is transported over the cooler Arabian Gulf waters, is advected to the site in the summer. Deep and very deep convective clouds are more common in March-April in association with organized convective systems, with generally reduced cloud cover from May to October. The region of interest exhibits a monthly-mean aerosol optical depth ranging from ∼0.3 in December-January to ∼1.2 in July due to its increased exposure to dust storms in the summer season. Dust activity is also found to peak during winter and spring associated with the intrusion of cold fronts from mid-latitudes.

Significant differences in the climatic conditions of the desert regions of Uzbekistan from the conditions of other oil and gas producing countries make it relevant to develop new types of overalls for workers in the oil and gas industry. The fabric of overalls for industrial workers used in the clothing industry has been studied. Taking into account that working clothes are made from these fabrics, studies were carried out to ensure that the fabrics meet the requirements of the state standard. At the same time, the quality indicators of textile fabrics made of cotton and blended fabrics are taken into account. The article studied the physical and mechanical properties of each textile fabric and the results were summarized in a special laboratory based on several indicators.

Dust storms and dust aerosols seriously affect environmental variation and climate change at regional and global scales. Accordingly, these hazards are the current focus in studies related to Earth science. The near-surface layer is an important link for the upward transmission of dust aerosols. However, the difficulty associated with obtaining real-time observation data from this layer has markedly hindered the progress of related research. In sand source areas, the topographic relief of natural dunes is easily ignored, despite serving as an essential factor affecting wind-driven dust emission, transport, and deposition. In this study, we explored the similarities and differences in horizontal dust flux (Q) between Xiaotang and Tazhong using observation data. In Xiaotang, the variation in the Q value with height was found to fit a power function; however, in Tazhong, the Q value did not show a significant gradient change. Such phenomena are caused by the secondary sand source generated by the undulation of natural dunes. The median particle diameter of the dust lifted from the ground during dust storms was essentially the same between Xiaotang and Tazhong, ranging from 74 to 82 μm in Tazhong and from 53 to 81 μm in Xiaotang. The maximum wind speed in Xiaotang was greater than that in Tazhong, resulting in a larger Q value for each particle size range in Xiaotang. The coarse sediment grain was identified as the main factor controlling the vertical variation trend of Q. Further, fine particles were found to have a minor impact.

Simulation studies have proposed a significant thermal effect of water ice clouds on the Martian atmosphere and climate. However, previous studies focused more on seasonal variations but less on short-term changes. In this work, we used the MCS multi-local time data to investigate the water ice diurnal variations on Mars. We quantified its diurnal variations with amplitude and phase by applying the tidal fitting method to the water ice abundance. In addition, we found a close correlation (antiphase relation) between the thermal tide and water ice diurnal variations during the aphelion seasons that was not sensitive to both the background water ice and dust opacity but increased with the tidal amplitude. In the perihelion seasons, the antiphase relation was sensitive to the water ice and dust opacity, both affected by the dust storm activity. Finally, the statistic results suggested an unexpected low threshold of diurnal tide amplitude (2 to 3 K) for generating a relevant water ice diurnal variation, accounting for the ubiquitous water ice diurnal variations in the Martian atmosphere. These new observational results can help further understand the phase transition process between ice and vapor in the Martian atmosphere and better constrain the Martian global climate model in the future. [ABSTRACT FROM AUTHOR]

Drying lakes have become a new source of dust, causing severe problems in surrounding areas. From 2000 to 2017, a statistical study was conducted on Lake Urmia in Iran in the Middle East. The results indicated a significant increase in the annual number of dusty days in stations around the lake and the mean annual aerosol optical depth (AOD) at 550 nm. The sharp decrease in annual snowfall rate over the Lake Urmia area since 2007 has been linked to the lake's decreasing water level and drying. During a dust storm event from 27 October to 31 October 2017, a local dust storm originated from Lake Urmia before another large-scale dust storm originated from the An-Nafud desert. According to MODIS true-color images, dust particles were lifted from Lake Urmia and transported eastward to the Caspian Sea and the HYSPLIT model. The comparison of the four models under the Sand and Dust Storm Warning Advisory and Assessment System (SDS-WAS) revealed that the models overestimated surface dust concentrations compared to ground-based PM10 measurements. Nevertheless, the NOAA/WRF-Chem and DREAMABOL models simulated higher dust concentrations during the dust period. More emphasis should be placed on the development of dust models for SDS-WAS models in Lake Urmia. [ABSTRACT FROM AUTHOR]

Long-range transport (LRT) can carry air pollutants to downwind areas. However, studies about the impacts of LRT on bacterial communities are few. This study investigated the influence of Asian dust storms (ADS) and frontal pollution (FP) on bacterial communities in ambient air using next-generation sequencing (NGS) and Terminal Restriction Fragment Length Polymorphism (T-RFLP). Air samples were collected at Cape Fugui (CF) and National Taiwan University (NTU) in northern Taiwan before (or background days), during, and after LRTs from November 2013 to March 2015. The richness, H index, and evenness increased during FPs and then decreased after FPs. During and after ADS and FP, the prevalence of the phylum Proteobacteria decreased, but that of Firmicutes increased. The dominant class of Proteobacteria changed from Alphaproteobacteria on background days to Betaproteobacteria during LRTs. At the genus level, the high abundance of Ralstonia and Bacillus during FP and Clostridium during ADS were detected at both locations. Additionally, Ralstonia was dominant at CF during ADS. In conclusion, FP and ADS both changed the bacterial community. The indicator genus was Clostridium and Ralstonia for ADS as well as Bacillus and Ralstonia for FP. Given the potential health threats posed by the bioaerosols transported, people should avoid outdoor activities during LRTs. [ABSTRACT FROM AUTHOR]

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Here we present observations of a dust storm that occurred on 22 February 2020 in the northwestern Sonoran Desert. In‐situ and remotely sensed measurements and output from numerical simulations suggest that evaporative cooling from cold frontal orographic precipitation spilling over an upwind mountain range generated a density current, with dust uplift occurring as the density current traveled over the emissive desert surface. Because the density current was laden with dust, time series of vertical profiles of aerosol backscatter and extinction from a ceilometer located 25 km downwind of the initial dust emission event show a well‐developed density current structure, including an overturning frontal head with a vertical extent of 1.2 km. Ceilometer measurements and soundings suggest a density current body depth of 400–500 m exhibiting a two‐layer structure that consisted of a positively sheared and dusty lower‐level, and a negatively sheared and pristine upper level. Kelvin‐Helmholtz instability at the top of the density current cold pool generated quasi‐regular oscillations in the height of the dust and pristine‐sky interfacial layer. Ridges and troughs in the height of this interfacial layer were coupled to maxima and minima in surface wind speed and near surface dust concentrations, respectively, with peak dust concentrations located directly under the interfacial layer ridges. These results corroborate several findings from model studies of dust emission and transport by density currents, and suggest that the internal circulation of a density current modifies the timing of dust emission and the patterns of dust concentration within the current body. Plain Language Summary: Here we discuss the case of a unique dust storm that occurred in the western end of the Sonoran Desert. Remote sensing and in‐situ measurements are used to demonstrate that the dust storm was generated by a density current. Lidar backscatter measurements during passage of this density current over a research site in the region are used to trace the path of dust laden air through the density current head and body, and reveal the internal circulation of this feature. These observational results corroborate findings from modeling studies of dust emission and transport by density currents, but also suggest a complex distribution of dust within the density current body. Key Points: Measurements of a dust storm in the western Sonoran Desert that was generated by a density current are presentedThe density current exhibits a 2‐layer internal circulation with a lower dusty layer and an upper pristine layerThese observations corroborate several findings from numerical simulations of dust emission and transport by density currents [ABSTRACT FROM AUTHOR]

Six dust storms that originated from Mongolia and moved to northern China in Spring 2021 are investigated by the anomaly variable‐based analysis method, which is compared to the traditional total‐variable based analysis method. Strong surface wind is a force to form dust storms as commonly known in current practice. However, dust area depicted by total‐wind model product analysis and operational forecast has a large bias to observation even for leading 24 hr. The analysis method of anomaly based variables showed that the domain of an airborne dust storm observed from satellite images is usually located between two neighboring convergence lines of 850 hPa anomalous winds. This connection of dust storm associated with the anomalous wind convergence extends southwestward from an anomalous cyclone and moves from Mongolia to northern China or Northeast China. It is thermodynamically associated with an anomalous thermal contrast, which has a spatial structure of wind, temperature, and geopotential height anomalies in the troposphere. We further found that numerical weather prediction products of the ECMWF model are able to indicate the anomalous wind pattern with lead times of 4–8 days by applying the anomaly based analysis approach. Therefore, this approach can not only depict dust area better but also reveal predictors much easier compared to the traditional total‐variable or full‐field‐based analysis method. Key Points: Dust storm can be well detected by the anomaly based analysis of atmospheric variablesA dust domain is located between two neighboring convergence lines of 850 hPa anomalous windsThe ECMWF model can predict the anomalous wind pattern for leading 4–8 days [ABSTRACT FROM AUTHOR]

Wind erosion is one of the most important natural processes in arid and semi-arid regions. Sistan plain has a hyper-arid climate and is one of the windy regions of the country. Due to the soil characteristics of the Sistan plain, wind erosion is very intense in this region. In this study, the relationships between some soil's physical and chemical properties and wind erosion were investigated in different land cover in a part of the central region of Sistan in 2018. A map of land cover in five classes was prepared using the results of field studies and the classification of satellite images. Fifty soil samples at a depth of 10 cm were collected to investigate the physical and chemical soil properties and the wind erosion threshold was determined at each location using a portable wind tunnel device. Also, the relationship between physical and chemical soil properties including soil texture, soil moisture, specific apparent weight, EC, SAR, ESP, Na+, k+, with the speed of wind erosion threshold was investigated. According to the results, the highest and the lowest threshold speed were 8.2 and 3.8 m s-1 and occurred in agricultural lands and hilly lands, respectively. The results of this study indicated that the velocity of wind erosion threshold in different lands adjacent to sandy areas is less than the average of that cover. Also, the soil texture, EC, and SAR have the most significant effect on soil wind erodibility at P <0.05 in the study area. [ABSTRACT FROM AUTHOR]

Mineral dust affects global and regional climates through radiative forcing. Herein the relationship between convective mixed layers and dust weather over arid and semi‐arid regions in East Asia is statistically analysed using operational surface‐station observation data and the lifting condensation level (LCL) height as a substitute for the mixed layer height. We divided the East Asia area into five regions (west/east Taklamakan Desert, west/east Gobi Desert and northeast China) and classified dust weather into three categories (floating dust, blowing dust and dust storm). Floating dust is the most frequent in the west Taklamakan Desert. All dust weather types are observed in the Taklamakan Desert even at low wind speeds but are seldom observed if the daily maximum LCL height is less than about 1,000 m. The floating dust events observed inside the Tarim basin seem to spread widely. In the Gobi Desert, when the maximum LCL height reaches about 3,000 m, all the dust weather types spread within the region. In all regions, the daily maximum LCL heights are higher in dust weather categories than in the no‐dust weather category. When a severe dust weather is observed in the Taklamakan and Gobi Deserts, the daily maximum LCL height reaches around 4,000–5,000 m above the mean sea level under higher wind conditions, suggesting that dust particles are easily raised from the boundary layer into the free troposphere during dust events in well‐developed mixed layer conditions. In the Gobi region, the frequency and areal extent of the blowing dust and the dust storm are higher than those of the floating dust. Therefore, the role of the deep mixed layers in the Gobi Desert is more important than that in the Taklamakan Desert. [ABSTRACT FROM AUTHOR]

This article proposes a novel dust-storm total path attenuation prediction model. This model is formulated as a function of specific attenuation (dB/km) and the effective distance, which considers the nonuniform dust storm intensity variations throughout the link. The effective distance is obtained as a combination of the total link distance and the reduction factor. The reduction factor is developed based on the modeled 2-D structure of the observed dust storm characteristics. A measurement campaign of atmospheric characteristics, their properties, and effects on several microwave links operated in Khartoum, Sudan, was conducted. In an earlier report, an empirical dust storm attenuation prediction model was proposed based on short-distance links by assuming uniform dust storm intensity variations. However, it was observed that the dust intensity varies with the distance, which affects total attenuation, and this issue is not addressed yet. One year measurement on the 6.2 and 7.6 km long microwave links operating at 21.2 and 14.5 GHz are used to validate the proposed dust storm total path attenuation model. [ABSTRACT FROM AUTHOR]

Dust storms have adverse socioeconomic impacts on human health and climate. The suspended dust in the atmosphere can also impact the radiation budget. In this study, radiative impacts of a dust storm in southern Iran are investigated during 20–25 November 2016 using the Weather Research and Forecasting model with Chemistry (WRF-Chem), in which the Goddard Chemistry Aerosol Radiation and Transport (GOCART) dust scheme is implemented. The WRF-Chem model calculates spatio-temporal variations of atmospheric variables and optical properties of suspended aerosols in the atmosphere. Two simulations have been conducted: a configuration without dust aerosols and a configuration with dust aerosols and their direct radiative forcing. Based on results of the WRF-Chem model, the pollution initiated in southern Iran on 21 November 2016. It is then intensified and transported toward southeast. The center of pollution was in the Persian Gulf and influenced the region until 25 November, with PM10 concentration reaching to more than 10000 μg m−3.The performance of the WRF-Chem model in terms of simulating the concentration and variation of dust during the event is satisfactory, such that horizontal and vertical distributions of the simulated and the observed dust are quite similar. During the period from 20 to 25 November, the highest reduction of horizontal visibility in southern Iran occurred between morning of 21 and morning of 22 November. Substantial reduction of horizontal visibility also occurred on 23 and 24 November, such that in Hormozgan, Sistan and Baluchestan, and Bushehr provinces, horizontal visibility reached to less than 1000 m during some hours. Maximum aerosol optical depth (AOD) also occurred on 22, 24, and 25 November. The performance of the model in terms of simulating the horizontal extension of the aerosol optical depth is similar to the Moderate Resolution Imaging Spectroradiometer (MODIS) products. Radiative effects of dust aerosols in southern Iran is associated with a reduction in the incoming shortwave and longwave radiation at the surface. The lowest and highest reduction of incoming shortwave radiation occurred in southeastern Iran and Bandar Abbas, respectively. The net radiation (sum of the shortwave and longwave radiation) at the surface is reduced during the dust event, which indicates cooling of the surface by dust aerosols. Results of this study indicates that variation of net radiation at the surface during the pollution period is directly correlated with high AOD values. Compared to the simulation without aerosols, both sensible and latent heat fluxes from the surface decrease in the simulation with aerosols. Our analysis indicates that dust aerosols decrease the net radiation at the surface. [ABSTRACT FROM AUTHOR]

By the combination of ground detection and satellite, the source and development process of strong dust storm in the northwest provinces, including Xinjiang, Gansu, Neimenggu, Ningxia, etc., occurred in November 17 to 18, 2016, is discussed by using the optical properties of aerosols. The ground detection equipments were used to measure the extinction coefficient and optical depth of dust aerosol near the source. The evolution path, formation process and cause of dissipation of dust storm were analyzed by satellite data. The reason why dust storm is not easy to spread to the eastern part of China is preliminarily given.

Abstract Aerosol particles, such as PM2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 µm), are an important yet variable component of our atmosphere; their presence defines the air quality and profoundly affects human health. In this project, we examine changes in the PM2.5 concentration, which is subject to temporal and spatial conditions and may vary by hour or day, in Lubbock, Texas, from 2001 to 2018. The hourly PM2.5 concentrations were measured at the local Texas Commission on Environmental Quality (TCEQ) station, analyzed for diurnal, weekly, monthly, seasonal, and yearly changes, and compared with meteorological parameters (such as the temperature, wind direction or speed, and visibility) recorded by the local National Weather Service station at Lubbock Preston Smith International Airport. In addition, we examined the effects of El Niño and La Niña on the PM2.5 concentration. The majority of the average daily PM2.5 values fell below the Environmental Protection Agency (EPA) daily threshold of 35 µg m−3, but many days exhibited high hourly concentrations, mainly due to dust storm events. No correlations were found between the concentrations and various meteorological parameters. Based on the hourly measurements, the diurnal distributions were bimodal, with morning and evening peaks, and the highest monthly averages were observed for April and June. A comparison of the PM2.5 concentrations during El Niño and La Niña revealed higher values during the latter, with the maximum concentrations occurring during weak La Niñas.

This study uses a high-resolution Weather Research and Forecasting model coupled with the chemistry module (WRF-Chem) to analyze the dust storm that occurred during 12‒17 June 2018 over the northwest Indo-Gangetic Plain (NW-IGP). The performance of WRF-Chem is validated against the ground- and space-based datasets before being used to investigate the impact of the dust storm on the air quality and radiative changes. The aerosols and meteorological parameters from in situ, satellite and reanalysis were used to evaluate the WRF-Chem model. The horizontal and vertical distributions of dust aerosols reproduced by the WRF-Chem agree with the observations. However, the WRF-Chem-simulated mean aerosol optical depth (AOD ~ 1.21 ± 0.17) is slightly underestimated compared to MODIS AOD (1.60 ± 0.32). Furthermore, the evolution of dust storm and associated changes in atmospheric and air quality conditions are well simulated by the WRF-Chem. The ERA5 and WRF-Chem suggest that the dust storm is triggered by the low-pressure system over the NW-IGP, which helps in bringing the dust-laden air masses from the west and southwest of the study region with the strong southwesterly winds. Our results reveal that the dust storm has a significant impact on air quality and horizontal visibility. During the peak time of the dust storm, the horizontal visibility dropped drastically from 4 to 0.48 km. In addition, the daily averaged in situ and model-simulated PM10 and PM2.5 concentration abruptly increased by a factor of two on peak time of the storm that deteriorated the air quality. The WRF-Chem-simulated dust-induced net radiative forcing shows the surface cooling (− 16.18 ± 3.88 Wm−2), atmospheric warming (+ 11.62 ± 4.96 Wm−2) and top of the atmospheric cooling (− 4.57 ± 0.92 Wm−2) due to the presence of elevated dust aerosols. [ABSTRACT FROM AUTHOR]

Martian dust plays a crucial role in the meteorology and climate of the Martian atmosphere. It heats the atmosphere, enhances the atmospheric general circulation, and affects spacecraft instruments and operations. Compliant with that, studying dust is also essential for future human exploration. In this work, we present a method for the deep-learning-based detection of the areal extent of dust storms in Mars satellite imagery. We use a mask regional convolutional neural network, consisting of a regional-proposal network and a mask network. We apply the detection method to Mars daily global maps of the Mars global surveyor, Mars orbiter camera. We use center coordinates of dust storms from the eight-year Mars dust activity database as ground-truth to train and validate the method. The performance of the regional network is evaluated by the average precision score with 50 % overlap ( m A P 50 ), which is around 62.1 % . [ABSTRACT FROM AUTHOR]

Dust storms are a major source of solid particles in the world that significantly impact air pollution and human and environmental health. Generally, trees and plants not only improve air quality by absorbing airborne particles on the surface of their leaves, but also they are affected by the accumulation of fine particles on their leaf surfaces. In this study, the uptake of fine dust by some dominant forest species of the Zagros region (Quercus Brantii Lindl., Q. libani Oliv., Q. infectoria Oliv. and Pistacia atlantica Desf.) was evaluated in the North Zagros Forests of Iran. For this purpose, soil, leaves and microdust on tree leaves were sampled by using a random systematic sampling network in the forests of Marivan County, Kurdistan province. The leaf ultrastructure of these species was examined by electron microscopy (SEM). Elements in the soil of the area and microdust deposited on the leaves of the trees were evaluated using the EDS (Energy Dispersive X-ray Spectroscopy) system and atomic absorption spectrometry. Finally, the ability of each hectare of forest to absorb fine dust was derived. Results showed that the leaves of all three oak species as well as wild pistachio are structurally different, which plays a distinct role in the deposition of microdust on tree leaves. The highest amount of microdust uptake by leaves was observed for Q. Brantii (0.012 g per leaf), followed by Q. infectoria (0.006 g per leaf) and Q. libani (0.005 g per leaf). In contrast, the lowest amount was observed for P. atlantica (0.0015 g per leaf). Based on the results, the amount of deposited dust in one hectare of forest in the study area with appropriate coverage (400 units per hectare) was estimated at 87.7 kg. The results of EDS test showed that the tested soil samples did not contain radioactive elements as well as heavy, toxic and dangerous elements. The results of the current study indicate the notable role of forest trees in the purification of air polluted by microdust as well as the the difference between species in their ability to absorb microdust. [ABSTRACT FROM AUTHOR]

As global temperatures continue to increase and human activities continue to expand, many countries and regions are witnessing the consequences of global climate change. Mongolia, a nomadic and picturesque landlocked country, has battled with ongoing desertification, recurring droughts, and increasingly frequent sandstorms in recent decades. Here we review the abrupt changes in the climate regime of Mongolia over the recent few decades, by focusing on atmospheric events, land degradation and desertification issues, and the resulted sandstorms. We found that between mid-March to mid-April 2021, the country encountered violent gusts of wind, the Mongolia cyclone, and the largest sandstorms in a decade, causing extensive damages nationwide and trans-regional impact in East Asia including northern China, Japan, and most parts of South Korea. A multitude of factors have contributed to this current ecological crisis. Since 1992, the country has transformed to a market economy with high economic growth driven by mineral and agricultural exports. Overgrazing along with intensified human activities such as coal mining has contributed to the widespread land degradation in Mongolia, while climate change has become a major driving factor for recurring droughts. Annual mean air temperature in Mongolia increased by 2.24 °C between 1940 and 2015, while annual precipitation decreased by 7%, resulting in a higher aridity across the country. A positive feedback loop between soil moisture deficits and surface warming has led to a hotter and drier climate in the region, with over a quarter of lakes greater than 1.0-km2 dried up in the Mongolian Plateau between 1987 and 2010. Increased temperatures, decreased precipitation coupled with land degradation have resulted in a persisting drying trend, with more than three-quarters of land in Mongolia being affected by drought and desertification. The 2021 East Asia sandstorms drew international attention to ecological issues that have culminated for decades in Mongolia. Collaborative efforts from policy makers, local residents, and scientists from both its local and the global research community are urgently needed to address the grand and rapidly aggravating ecological challenges in Mongolia. [ABSTRACT FROM AUTHOR]

An unseasonal dust storm hit large parts of Central Asia on 4–5 November 2021, setting records for the column aerosol burden and fine particulate concentration in Tashkent, Uzbekistan. The dust event originated from an agropastoral region in southern Kazakhstan, where the soil erodibility was enhanced by a prolonged agricultural drought resulting from La Niña-related precipitation deficit and persistent high atmospheric evaporative demand. The dust outbreak was triggered by sustained postfrontal northerly winds during an extreme cold air outbreak. The cold air and dust outbreaks were preceded by a chain of processes consisting of recurrent synoptic-scale transient Rossby wave packets over the North Pacific and North Atlantic, upper-level wave breaking and blocking over Greenland, followed by high-latitude blocking over Northern Europe and West Siberia, and the equatorward shift of a tropopause polar vortex and cold pool into southern Kazakhstan. Our study suggests that the historic dust storm in Uzbekistan was a compound weather event driven by cold extreme, high winds, and drought precondition.

Background: Despite the fact that Iran has been exposed to severe dust storms during the past 2 decades, few studies have investigated the health effects of these events in Iran. This study was conducted to assess the association between dust storms and daily non-accidental, cardiovascular, and respiratory mortality in Dezful City (Khuzestan Province, Iran) during 2014 to 2019. Methods: In this study, mortality, meteorological, and climatological data were obtained from the Dezful University of Medical Sciences, Iranian Meteorological Organization, and Department of Environment in Khuzestan Province, respectively. Days of dust storm were identified based on the daily concentration threshold of particulate matter with an aerodynamic diameter of less than 10 μm (PM10) according to Hoffmanns҆ definition, and then an ecological time-series was used to estimate the short-term effects of dust storms on daily mortality. Statistical analysis was performed using a distributed lag linear model (DLM) and a distributed lag non-linear model (DLNM) packages by R software and the study results were reported as excess mortality. Results: During the study period, 15 223 deaths were recorded, and 139 dust storms occurred in Dezful city. In addition, there was statistically significant excess risk of mortality due to dust storms in Dezful City (mortality in the group under 15 years of age, lag4: 34.17% and 15-64 years of age groups, lag5: 32.19%, lag6: 3.28%), also dust storms had statistically significant effects on respiratory mortality (lag6: 5.49%). Conclusion: The findings of the current study indicate that dust storms increase the risk of mortality with some lags. An evidence-based early warning system may be able to aware the people of the health effects of dust storms. [ABSTRACT FROM AUTHOR]

Convective dust storms, or haboobs, form when strong surface winds loft loose soils in convective storm outflow boundaries. Haboobs are a public safety hazard and can cause a near instantaneous loss of visibility, inimical air quality, and contribute significantly to regional dust and radiation budgets. Nevertheless, reliable predictions of convective dust events are inhibited by a lack of understanding regarding the complex and non‐linear interactions between density currents, or convective cold pools, and dust radiative effects. In this study, the Weather Research and Forecasting model coupled with Chemistry (WRF‐Chem) is utilized to simulate the effect dust radiation interactions have on a long‐lived haboob case study that spans three distinct radiative regimes: day (high shortwave), evening (low shortwave), and night [longwave (LW) only]. A sophisticated algorithm is used to track and identify the numerous convective old pool boundaries in the simulations and assemble statistics that represent the impact of dust radiative effects. To first order, dust scattering of shortwave radiation in the day leads to a colder, dustier, and faster moving convective cold pool. In the transition period of early evening, the shortwave effects diminish while LW dust absorption leads to warmer, slower density currents that loft less dust as they propagate. At night, the haboob is again warmer due to dust absorption, but gustier in the more stable nocturnal surface layer, leading to enhanced dust emissions. Plain Language Summary: When rain evaporates below clouds in a thunderstorm, it can produce strong, cold winds at the surface. If the surface is dry and contains loose soils, these strong winds can lift dust into the air, and create a dangerous type of dust storm called a "haboob." The dust inside a haboob can be a safety hazard, but is also a critical contributor to marine ecosystem fertilization, hurricane formation, and the Earth's climate because dust redirects and absorbs incoming energy from both the sun above and the Earth below. Depending on how dust interacts with this energy, it can have opposite effects and either warm or cool the air around it. Therefore, the strong, cold winds from the thunderstorm that created the haboob in the first place can become either colder (stronger, faster) or warmer (weaker, slower). When forecasting and issuing warnings to the public, it is important to know the strength of the haboob and how fast it will move. This study investigates when and how the dust inside a haboob can cool the dust storm and make it stronger, versus when the dust will warm the dust storm and make it weaker. Key Points: Daytime dust scattering leads to colder, stronger density currents with higher windspeeds and dust emissionsIn the evening, longwave dust absorption leads to a warmer surface and warmer, weaker cold pools with suppressed winds and dust emissionsAt night, dust absorption leads to less stable and warmer cold pools with higher windspeeds, turbulence, and dust emissions [ABSTRACT FROM AUTHOR]

We report seasonal and dust‐related variations in neutral and ion species (CO2, O, and N2, and CO2+, O2+, O+, and N+, respectively) in the dayside Martian upper atmosphere between altitudes of ∼150 and ∼250 km observed by the Neutral Gas and Ion Mass Spectrometer aboard the Mars Atmosphere and Volatile Evolution spacecraft. The sinusoidal seasonal variations in CO2+ and O2+ densities are clearly identified, while that of O+ is less discernible. These observed variations in ion densities are well reproduced by a photochemical equilibrium model for CO2+ and O+ densities when we combine them with solar cycle variations. Furthermore, we find a decrease in O, O+, and O2+ densities in the whole altitude range at Ls = 342–346 in MY 33 during a regional dust event. The decrease in O density would lead to decreases in O+ and O2+ densities in the ionosphere through ion‐neutral reactions. Observed variations in ion and neutral species associated with the season and a regional dust storm are also confirmed in pressure coordinates. Observations show that the CO2+/O+ ratio at a given pressure level in the ionosphere varies by a factor of ∼3, which can modify the composition of ion outflow from the Martian atmosphere. Plain Language Summary: Early Mars had a dense CO2 atmosphere that could sustain a significant amount of liquid water, but present Mars only has a 7–9 mbar CO2 atmosphere. Many CO2 gases are considered to have been lost to space. One of the mechanisms for atmospheric escape on Mars is the acceleration of the ion species in the ionosphere by the interaction with the solar wind. Since ionospheric ions can be the source of escaping ions, variability in the number density in the ionosphere might affect the escape rates. The Neutral and Gas and Ion Mass Spectrometer aboard the Mars Atmosphere and Volatile Evolution spacecraft can provide a long‐term data set of number densities and composition in the ionosphere and thermosphere. We investigated the compositional change in number densities in the ionosphere and thermosphere because they are coupled through ion‐neutral reactions. Seasonal variations in neutral and ion densities are observed, and we find that the number densities of O, O+, and O2+ decrease when a regional dust storm occurs in the lower atmosphere. Key Points: Seasonal variations in CO2+ and O2+ in the ionosphere are significant, while those in O+ are less discernibleThe observed variations in CO2+ and O+ are well reproduced by a photochemical equilibrium modelDecreases in O, O+, and O2+ densities in the thermosphere and ionosphere are found during a regional dust storm [ABSTRACT FROM AUTHOR]

The increasing demand for high-speed information transmission as a result of adoption of wide variety of multimedia applications including high-definition television, social networking, and live streaming etc. has challenged the service providers. The conventional wireless transmission systems based on radio frequency are unable to meet the high channel capacity requirements. We design and demonstrate a novel radio-over-free space optics (RoFSO) communication system using hybrid wavelength- and mode-division multiplexing (WDM-MDM). The present RoFSO system consists of four transmitter subsections, four-channel MDM multiplexer/demultiplexer, four-channel WDM multiplexer/demultiplexer, and four receiver subsections. Each channel uses four distinct spatial modes (HG00, HG01, HG02, and HG11) which transport independent 10-Gb/s-10-GHz information over a wavelength range of 850–852.4 nm. We achieved a net system transmission rate of [4 λ × (4 modes) × (10 Gb/s-10 GHz)] i.e. 160-Gb/s-160-GHz. Also, we demonstrate the WDM-MDM-based RoFSO link performance and availability under clear and dust weather conditions using bit error rate, maximum reachable link range and eye diagrams as key performance evaluation parameters. The results showed a successful data transfer through 8 km clear weather free-space channel and 88 m dense dust weather conditions, respectively. Subsequently, the results show the feasibility of presented system in the implementation of high-speed ultra-dense cellular/data 5G networks (above 6 GHz) and smart city applications. [ABSTRACT FROM AUTHOR]