Dusty Days Research Articles

Temporal and spatial pattern of dust storms, their polycyclic aromatic hydrocarbons, and human health risk assessment in the dustiest region of the world.

This study evaluated the concentration and health risks of polycyclic aromatic hydrocarbons (PAHs) in Abadan City under 4 different climatic conditions: normal days, dusty days, dust with northwesterly winds, and dust with southeasterly winds. It also determined the sources of aromatics and discussed the relationship between meteorological parameters and PAH concentrations. The spatiotemporal distribution of dust in the area was determined using the HYSPLIT (hybrid single-particle Lagrangian integrated trajectory) back trajectory model, moderate resolution imaging spectroradiometer (MODIS) images. For this purpose, sampling was performed for 70days using an Omni device. The concentrations of 16 PAHs (USEPA) ranged from 46.22 to 90.96ng/m3. The highest concentration of high molecular weight (HMW) PAHs was 4-6 rings, of which 4 rings were predominant in all samples. PAH sources were identified using diagnostic ratios and principal component analysis (PCA), and it was shown that PAHs mainly originate from a mixture of sources, including vehicular emissions, petrol emissions, and traffic. Wind speed was negatively correlated with dust, except on dusty days. This result indicates a decrease in PAH concentrations when wind speed increases. On the other hand, the dust correlation with PAH was positive on normal days, but a negative correlation was observed on dusty days. This result was due to the lower concentration of PAHs from natural resources (such as dust source areas) vs. human resources (such as traffic and industry). PAH health risk assessment in Abadan City showed that the risk of carcinogenesis was higher on normal days and through skin contact. The probability of incremental lifetime cancer risk (ILCR) in all sampling conditions was potential in terms of carcinogenic risk (10-4-10-6). As a critical risk factor, relevant authorities should prevent, control, and reduce it.

Effect of dusty weather on the performance of the PV/Trombe wall: Experimental assessment

The current article studies the effect of dusty weather conditions on the performance of PV/Trombe wall Photovoltaic. Two experimental models were built to study the impact of climatic changes and operating conditions on the PV/Trombe wall, one with DC fans and the other without DC fans. The operating conditions for dusty and non-dusty days were tested to show their impact on system efficiency. In the case of the model using DC fans on a clear day, the electrical and thermic efficiency of the model reached 10.2% and 17.6%, respectively. While in the case of the model without DC fans and on a clear day, the electrical and thermic efficiency of the model reached 8.4% and 40.1%, respectively. In the case of the model using DC fans on a dusty day, the electrical and thermic efficiency of the model reached 6.6% and 11.9%, respectively. While in the case of the model without DC fans and on a dusty day, the electrical and thermic efficiency of the model reached 3.5% and 34.1%, respectively. Dusty weather conditions reduce the electrical efficiency of the PV/TW system; the average daily electrical efficiency increase was 2.4% under clear weather conditions compared to dusty weather conditions. Also, the dusty weather conditions lead to an apparent decrease in the temperatures of the solar panel and air in the room. The decrease was 12% compared to a clear day.

Anatomical changes in dwarf shrub roots provide insight into aeolian erosion rates in northeastern Iceland

Iceland is known for having strong aeolian erosion events, as evidenced by erosional escarpments on the soil surface; these are known locally as rofabards. The aim of the study was to estimate aeolian erosion rates at two research plots affected by severe erosion, using anatomic features of the roots of Arctic, woody, dwarf shrubs. Ours is the first study to utilize dendrochronological analyses of exposed roots of dwarf willows (Salix herbacea L.) as an indicator of aeolian erosion. When dwarf shrub roots are exposed to the atmosphere by erosion, cell sizes are reduced by >50 %, with maximum changes in individual plants exceeding 150–200 %. We detected the erosion signal by analyzing changes in cell-size and width of growth rings in the roots. Using this relationship, were able to estimate erosion rates (the retreat of escarpments) since the 1970s for the study area. During the 1970s and 1980s, erosion rates were fairly constant, with retreat ranging from 1.0 to 2.5 cm yr−1. Rapid increases in erosion rates were observed after the late 1990s, occasionally as much as 4.4–5.4 cm yr−1. Increased aeolian erosion rates may be linked to continuous heavy grazing by sheep and climate change, as this period coincides with increased numbers of hot and warm, and dusty days. Our results indicate that dendrochronological methods can be highly useful in determining past geomorphic activity, due to modern environmental changes observed in the Arctic. The methods employed here can be applied even in treeless areas.

Dust mitigation by the application of treated sewage effluent (TSE) in Iran

Considering the presence of 274 dusty days in 2021 in Zabol city, Iran, the present study aimed to evaluate the feasibility of using treated sewage effluent (TSE) for dust mitigation with natural methods of increasing land cover. Hence, first of all, the identification of sewage treatment facilities along with the volume and chemical status was carried out and compared to the various national and international legislation. Then, field investigation on land use and land cover, along with literature review on dust origins, sand detachment areas, and sand corridors in the study area will be assisted for optimal area suggestion. Note that, in the present study it was assumed that the application of TSE for wetting the surface to vegetation restoration resulted in wind erosion control in critical foci. The results showed that, so far, a total of 39,000 m3/day could be treated, in the whole study area. The TSE volume calculated based on two scenarios consisting, (1) data obtained from the related organization, and (2) based the capacity of the wastewater plant is 2.8 and 5.1 mcm/year, respectively. Additionally, the study of TSE quality and its comparison to various regulation such as FAO, USEPA, INS, and CWQI indicated the applicability of transforming TSE to 14 km away from the WWT planet daily for rehabilitation of Hammon Hirmand through irrigation of T.stricta to increase the vegetation cover to above 30%.

An Investigation Into the Effect of Dust on Wheat Yield

Different regions of Iran are influenced by dust storms since they are located in the arid and semi-arid zone and due to their plain structure, the penetration of different synoptic systems, and adjacency with desert and important dust centers. This research investigates the effect of dust sedimentation on the yield of irrigated and rainfed wheat in four neighbouring provinces and on wheat production in Iran (Khuzestan, Ilam, Kermanshah, and Lorestan). Data are for the crop years from 2011–2012 to 2018–2019. For higher accuracy, the research studies irrigated and rainfed wheat systems separately with the panel model of the Just–Pope function. In the Just–Pope stochastic function, the effects of inputs on two indices of mean yield and yield variance are studied simultaneously. Based on the results, the risk function of irrigated wheat is significantly influenced by the variables of machinery, labour, and dust at the 1% level and by the variables of water and precipitation at the 10% level. The most influential variable in this function is dust (3.03%). In the risk function of rainfed wheat, all variables have a significant impact on production fluctuations at the 1% level. The most influential factor is the temperature (0.86%). Furthermore, the results reveal that the variable of the number of dusty days is significant in the production of irrigated and rainfed wheat at the 15% and 1% levels, respectively. The effect of this variable on rainfed wheat is negative and 0.101%. In this regard, it is necessary to develop dust-specific projects in the agricultural sector and estimate the cost imposed by this phenomenon.

Assessment of aeolian dust concentration, elemental composition, and their wet and dry deposition fluxes over the Northeast Arabian Sea

ABSTRACT Atmospheric aerosol over the Arabian Sea is significantly impacted by the long-range transported mineral dust from the surrounding continents. This transported mineral dust is hypothesized and tested during several studies to see the impacts on the surface ocean biogeochemical processes and subsequently to the Carbon cycle. It is, thus important to quantify dust contributions and their fluxes to the Arabian Sea. Here we assess temporal variability of dust concentration, their elemental characteristics as well as quantify their dry and wet deposition fluxes over the North-eastern Arabian Sea. The dust concentrations were found to vary from 59 to 132 µg m−3 which accounts for 50% to 90% of total mass during dusty days. However, its contribution during pre and post dust storms ranges between 6% and 60%. Relatively higher dust dry deposition flux of 28 ± 7 mg m−2 day−1 (range: 20–44) is estimated for dusty days compared to pre and post dusty days (range: 0.4–22 mg m−2 day−1). In contrast to dry deposition fluxes, significantly higher fluxes are estimated from wet deposition, averaging around 240 ± 220 mg m−2 day−1. These values are five times higher than those reported from cruise samples collected over the Arabian Sea. The contribution of dust to aerosol mass is further ascertained using elemental composition, wherein a significant correlation was observed between Fe and Al (r2 = 0.77) for samples collected during the dusty period, highlighting their similar crustal sources. Our estimation of dust flux over this region has implications for the supply of nutrients associated with natural dust to the surface water of the Arabian Sea. Implications: The Arabian Sea, one of the productive oceanic regions among the global oceans, has been identified as a perennial source of atmospheric CO2. This basin is heavily impacted by atmospheric dust deposition/inputs owing to its geographical location being surrounded by arid and semi-arid regions. It has been hypothesized that aeolian dust plays a significant role in modulating surface water biogeochemical processes including primary productivity, in the Arabian Sea. Furthermore, modelling studies have highlighted on the role of dust (containing Fe) in fueling and enhancing primary productivity in the Arabian Sea. However, quantification of dust deposition fluxes (wet and dry) on seasonal time scale is missing in the literature. This paper aims to partially fulfil this research gap by providing a long-term data of wet and dry deposition fluxes over the northeastern Arabian Sea. We have also discussed their seasonal variability and factors affecting this flux. Thus, this study will be valuable contribution to the aeolian research community and have significant implication toward the role of aeolian deposition to the surface water biogeochemical processes in the Arabian Sea.

The Relationship Between Dust Sources and Airborne Bacteria in the Southwest of Iran.

The biological agents are carried from deserts and dried lands to long distances by high dust volumes. Their adverse effects can be reduced by specifying and controlling dust sources and their related biological agents. Thus, the current work examined the relationship between the bacteria in air and soil samples by taking samples from the soil surface of two dust sources, as well as from air samples during spring from Khorramshahr and Abadan cities. The dust event is the most influential factor on airborne bacteria. There is an insignificant negative (-0.06), insignificant positive (0.14), and weak positive (0.24) correlation between airborne bacteria and UV radiation, relative humidity, and temperature, respectively. After preparing a 16S ribosomal DNA (rDNA) clone library from the soil and air samples, operational taxonomic unit picking and taxonomic assignment were conducted using QIIME Virtual Box. In the present work, Bacillus was the dominant species. The relationship between dust sources and air samples was determined by principal component analysis. Bacteria in the Hoor-Al-Azim dust source and airborne bacteria on dusty and non-dusty days showed a more significant correlation compared to bacteria in the Shadegan dust source. Source Tracker software was used to estimate the contribution of dust sources. The primary source of dust was associated with the dried areas of Hoor-Al-Azim on the non-dusty and dusty days. Finally, the long transport of airborne bacteria was assessed by moderate resolution imaging spectroradiometer (MODIS) and the back trajectory model of Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) data. The research findings can help decision-makers prioritize dust sources to control the adverse effects of dust.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11356-022-21563-6.

Regional Analysis of Dust Day Duration in Central Iran

The duration of dust days (DDD) is one of the most important parameters that may worsen the effects of the presence of dust in the affected areas. Persistent pollution over consecutive dusty days can have particularly negative effects on the human respiratory system. The present analysis was conducted in Central Iran, where the phenomenon of dust is one of the most important problems. In this study, using dust codes recorded at 35 synoptic stations, the homogeneity of DDD across the region was investigated using the L-moments method. Then, characteristics of DDD over the period 1999–2018 were calculated. The results showed that the region is statistically homogeneous. Furthermore, Zabol and Zahdan are the stations worst affected, with the longest durations of 22 and 21 days in 2014. Additionally, the values of DDD with return periods of 5, 10, 25, and 50 years were calculated using fitted statistical distributions and kriging and mapped. Finally, using the K nearest neighbor method the most important factor affecting DDD of the spatial characteristics, including longitude, latitude, elevation, average daily temperature (tm), dew point (td), wind altitude (u), maximum wind speed (ffmax), and direction of the fastest wind (ddmax), was determined. It was found that the southeastern parts of the study area are affected by the longest dust storm duration in all return periods; over longer return periods, long dust storms are also found in the central parts, especially the central desert of Iran. Therefore, these areas should be given priority in fighting and controlling wind erosion. Furthermore, the results showed that the maximum wind speed has the greatest effect on DDD.

Geomorphological and spatial analysis of dust sources in Ilam Province, Iran

Dust storms, which have become an environmental crisis in the Middle East in recent years, are associated with increased sources of sediment production. There are several reasons for the emergence of these sources, with the interplay between geomorphological processes and the production of landforms, which are susceptible to dust emission under certain conditions, being considered as its main reason. In this research, the most important dust production regions in Ilam province, located in the west of Iran, have been identified and their geomorphological characteristics have been analyzed in order to manage the environment. First, using MODIS images, applying the thermal-infrared dust index (TDI) and the HYSPLIT model during 21 dusty days from 2008 to 2013, the dust source areas were identified. Subsequently, a geomorphic map was produced and overlaid on the dust source map to determine the distribution and frequency of dust source points in each geomorphic class. Finally, field observations were conducted to analyze the geomorphological characteristics of the most important dust emission areas. The results revealed heterogeneity in the spatial distribution of dust sources in the area (235 points) concentrating in the regions of Mehran, Dehloran and Abu Ghovair where poor rangelands and agricultural lands predominate and abundant supplies of alluvial sediments exist. Indeed, dust mostly originates from landforms such as alluvial fans and floodplains whose dust-sized particles are renewed by seasonal floods annually. Thus, the availability of fine particles (clay and silt) in various geomorphic units plays a significant role in determining the dust emission capacity.

Analyses of a Lake Dust Source in the Middle East through Models Performance

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.

Health Effects of Dust Storms on the South Edge of the Taklimakan Desert, China: A Survey-Based Approach.

Dust storms have already become the most serious environmental problem on the south edge of the Taklimakan desert because of their frequent occurrences. To investigate the health effects of dust storms on public health in Moyu County, one of the most severe dust-storm-affected areas located at the south edge of the Taklimakan desert, China, primary data were collected from 1200 respondents by using a questionnaire survey for 15 health symptoms. The data were analyzed by comparing the mean tool (independent t-test and ANOVA) and the severity of different symptoms among different age groups. Principal component analysis (PCA) was applied to further analyze the multivariate relationships between meteorological factors, dust storm intensity, air pollution level, and severity degree of the different symptoms. The results show that significant correlations exist between dust storm intensity, air pollutants (PM2.5, PM10, O3, SO2, NO2, and CO), meteorological factors, and health symptoms. During dusty weather, no matter the age group, the number of respondents who suffered from different health symptoms was higher compared to non-dusty days. Three types of dusty days were considered in this study: suspended dust, blowing dust, and sand storms. The impacts of sand storm weather on public health are stronger than those from blowing dust weather, suspended dust weather (haze), and non-dust weather. The people in the age groups above 60 years and below 15 years were more sensitive to different dust weather than people in the age groups between 15 and 60. “Dry throat with bitter taste”, “Depression”, “Dry and itchy throat”, and “Mouth ulcer” are the main symptoms caused by dust storms.

Fossil water: Last resort to resolve long-standing water scarcity?

Sistan is a drought-affected region in the southeast of Iran, dependent on the variable surface water inflow from the Helmand River basin in Afghanistan. The river flow has recently experienced sharp annual fluctuations in Afghanistan, resulting in a collapse of the agriculture and ecosystem in Sistan. Therefore, the authorities have recently decided to rely on non-renewable groundwater (fossil water aquifers) resources to support the current developments in Sistan. The current study aims to assess the adequacy of fossil water aquifers to back the water demand in scarcity. A system dynamics model for the Sistan Water Resources System (SWRS) is developed to analyze the complicated water management system in the basin, which considers major hydrological, socioeconomic, agricultural, and, specifically, environmental aspects. The results show that the water resources in Sistan are incredibly unreliable and vulnerable due to their dependence on the surface water inflow from Afghanistan. Fossil aquifer withdrawal can address the current water problems in Sistan. However, fossil water over withdrawal without considering the critical level of aquifers can eventually lead the project to fail. Unmanaged use of fossil aquifers in Sistan has the characteristics of a "Limits to Growth Archetype" system, with negative and dangerous effects in the long run. In the environmental subsystem, meeting the minimum environmental demand is demonstrated as the effective way to stabilize the soil of the lake and considerably reduce dusty days. Further, fossil aquifer exploitation and demand management by increasing irrigation efficiency and reducing wastage of reservoirs have a great impact on the sustainability of the agricultural sector.

Wind as a back-up energy source for mars missions

This paper examines if wind might be an additional energy source for solar powered, crewed Mars missions during dusty days. Wind data from Viking Lander 2 is analyzed from a wind engineering point of view, as it is done on Earth, to evaluate wind turbine sites. It is assumed that wind energy will not be the primary energy source used on a crewed Mars mission but an additional option during times of global dust storms, when solar power is suffering from an increase of atmospheric optical depth, which is seen as one of the largest drawbacks of solar arrays. In order to evaluate if wind energy might be a reliable energy source during dust storms, when the energy yield of solar cells is reduced, it will be investigated whether wind strength has a positive correlation with increased atmospheric optical depth. This is, in case wind speed is generally capable of providing a significant amount of power, a further requirement if wind turbines should compensate the power loss of solar arrays during increased atmospheric optical depth. For a first estimate of the amount of wind turbines needed to maintain energy output during a storm a case study is done which regards power production during the 1977b global dust storm.

Assessing the relationship between airborne fungi and potential dust sources using a combined approach.

Dust events impose negative socio-economic, health, and environmental impacts on vulnerable areas and reflect their sources' physiochemical and biological characteristics. This study aimed to assess the impact of two dust sources on the concentration and diversity of airborne fungi in one of the dustiest areas in the world. This study is the first attempt to investigate the relationship between dust sources fungal community and those in airborne dust. Also, the contribution of dust sources to airborne fungi was estimated. Air masses arriving at the study area were assessed using local wind rose and the HYSPLIT model. Sampling was carried out from airborne dust at the Arvand Free Zone as target areas and soil in the dried parts of the Hor al-Azim and Shadegan wetlands as source areas to explore the relationship between fungi in the dust sources and the downwind area. The samples were analyzed in the lab to extract DNA. The internal transcribed spacer (ITS) regions of the rDNA gene were amplified using the primers ITS1F and ITS4, and then PCR products were sent to the lab for sequencing. The raw DNA data were processed using the QIIME virtual box to pick operational taxonomic units and taxonomy assignments. The most common fungi at the genus level were in the order of Penicillium > Aspergillus > Alternaria > Fusarium > Paradendryphiella > Talaromyces. The similarity between air and soil fungal genera was investigated using richness and diversity indices, the phylogenetic tree, and principal component analysis. The results showed that the community structures of ambient fungi in the Hor al-Azim and Shadegan dust sources were more similar to those on dusty days than non-dusty days. The source tracker model was used to quantify the contributions of known dust sources to airborne fungi. The results showed that the main source of airborne fungi was Hor al-Azim on dusty and non-dusty days. This study's results can help managers identify and prioritize dust sources regarding fungal species.

Analysis of aerosol optical and microphysical characteristics over Yinchuan (China) in 2019

ABSTRACT Using the European Skynet Radiometers (ESR).pack algorithm and data obtained in the Yinchuan (China) area in 2019 using a Cimel CE-318 sun photometer, this study inverted aerosol parameters such as optical depth, volume size distribution, phase function and single scattering albedo. Additionally, the HYSPLIT backward-trajectory model was used to establish the source characteristics of the aerosols in each season and to determine their climatic impact. Results showed that aerosol optical depth had an evident seasonal trend of change, reaching a maximum (minimum) in spring (summer), and continue to rise in autumn and winter. The relationship between aerosol optical depth and the Ångstrom exponent in each season showed that the types of aerosol in the Yinchuan area changed little between seasons, comprising mainly mixed aerosols followed by continental clean aerosols. The volume size distribution presented a bimodal shape, reflecting that the peak of fine (coarse) particles increased significantly on hazy (dusty) days. Moreover, the biggest change in the trend of the volume size distribution was in summer. The phase function distribution revealed evident side and back scattering by dust aerosol particles. Change in the single scattering albedo on both hazy and dusty days was reasonably stable, but the value on dusty days was larger than that on hazy days. The single scattering albedo was largest (smallest) in summer (winter). Moreover, the clustering results of wind field trajectories show that the Yinchuan area is greatly affected by the wind field from the north throughout the year. The findings of this study have particular importance regarding research into the characteristics of aerosol parameters using CE-318 sun photometers at sites that are not part of the global AErosol RObotic NETwork (AERONET) project.

Observation and Inversion of Aerosol Particle Size Distribution over Yinchuan Area

Particle size distribution is one of the important microphysical parameters to characterize the aerosol properties. The aerosol optical depth is used as the function of wavelength to study the particle size distribution of whole atmospheric column. However, the inversion equation of the particle size distribution from the aerosol optical depth belongs to the Fredholm integral equation of the first kind, which is usually ill-conditioned. To overcome this drawback, the integral equation is first discretized directly by using the complex trapezoid formula. Then, the corresponding parameters are selected by the L curve method. Finally the truncated singular value decomposition regularization method is employed to regularize the discrete equation and retrieve the particle size distribution. To verify the feasibility of the algorithm, the aerosol optical depths taken by a sun photometer CE318 over Yinchuan area in four seasons, as well as hazy, sunny, floating dusty and blowing dusty days, were used to retrieve the particle size distribution. In order to verify the effect of truncated singular value decomposition algorithm, the Tikhonov regularization algorithm was also adopted to retrieve the aerosol PSD. By comparing the errors of the two regularizations, the truncated singular value decomposition regularization algorithm has a better retrieval effect. Moreover, to understand intuitively the sources of aerosol particles, the backward trajectory was used to track the source. The experiment results show that the truncated singular value decomposition regularization method is an effective method to retrieve the particle size distribution from aerosol optical depth.

Identification and zoning of dust phenomena using satellite remote sensing

Background and Objective: Dust phenomena occur frequently in arid and semi-arid regions. Iran is always exposed to dust storms due to its geographical location. The paper aimed to highlight and map the dust phenomena using meteorological meteorological parameters and satellite images and the number of dust days of 20 synoptic stations in the period 2010 to 2017.Materials and Methods: In this study, Madis sensor images were used in accordance with the date of dusty days at the station. Visual interpretation methods with color combination and TDI and BTD dust indices were applied to highlight dust phenomenon. After highlighting the dust, dust zoning was done by interpolation methods. Then the correlation between the data with horizontal visibility less than 1000 m and meteorological parameters was evaluated and analyzed using regression method. The highest and lowest correlation coefficients (R ^ 2) of BTD and TDI dust indices with meteorological parameters, respectively.Results: The results of climatic data analysis showed that the highest storms were recorded in Ahvaz, Omidieh, Aghajari, Abadan, Behbahan, Hendijan, Bandar Mahshahr stations in 2012 (2012). The highest impact of walnut dust was in the southern meteorological stations of Khuzestan province near Iraq and Saudi Arabia. Therefore, foreign dusts are considered to have entered the southwestern and western parts of Iran from neighboring countries.

Linking ground-satellite observations with HYSPLIT Back trajectory modeling to identify dust sources affecting Western Iran: A case study in Lorestan province

Background: This study combined ground and satellite observations with the results of HYSPLIT model to identify the origin, transport, and deposition of sand and dust storms (SDSs) affecting Western Iran. Methods: Field-measured dust exposure data were obtained during 2000-2014 to analyze variability of dust concentration and dust intensity at annual, monthly, and daily scales. Remote sensing measurements in this research include the analysis of a total of eight (Level 1B Calibrated Radiances 1 km (MOD021KM)) MODIS tiles selected based on interpreting the results of ground observations to capture the major SDS events occurred between 2000 and 2014. Results: The results, indicating a sharp rise in the number of dusty days from 2008 onwards, were used as a basis to identify the spatial coverage and intensity of SDSs over the central part of the Middle East and the study province using a number of eight MODIS images. According to the back trajectory analysis of Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT), the MODIS-derived SDSs were found to have both national and international sources. The most prevalent and powerful source was likely to initiate from deserts of Syria and Iraq by air masses coming from the Mediterranean Sea and terminate in Western Iran where the Zagros Mountains Chain blocks easterly winds. Conclusion: Despite the evident link between timing of regional SDSs and in situ observations, the contribution of local dust sources in the west of the province should be also investigated to provide insights into the development and spread of SDS events affecting Western Iran, especially Lorestan Province.

Dust storm surveying and detection using remote sensing data, wind tracing, and atmospheric thermodynamic conditions (case study: Isfahan Province, Iran)

One of the most important environmental problems in recent years in the Middle East including Iran is the dust storm events. The main goal of this research was to conduct statistical analyses to identify the dusty days with visibility to less than 1 km. This study also dealt with the recognition of sources of this phenomenon and the route for dusts to enter Isfahan Province. In this study, data were collected for a 20-year period (1994–2013) including daily dust data at the ground stations, brightness temperature at wavelengths of 11 μm and 12 μm, and GDAS data for tracking the dust particle route in HYSPLIT software. Naein and Airport stations with frequencies of 920 and 919 days of dust (respectively) were identified as two critical centers of dust in Isfahan province. The spring season had the highest number of days with dust. Also, the highest and lowest frequencies of this event were observed in April–May–June and December–January, respectively. The border area between Iraq and Syria, west and southwest of Iraq, was the main source of the dust transported to Isfahan. Thermodynamic conditions of atmosphere using the Skew-T diagrams were stable during the dust events in the study area.

Study on short-term optimal operation of cascade hydro-photovoltaic hybrid systems

Formulating an optimal operation strategy is a real challenge in the actual operation stage of a hybrid system. This study presented a research framework for determining the short-term optimal operation strategy for cascade hydro-photovoltaic hybrid system. First, a method was presented for describing the cascade hydro-photovoltaic hybrid system net load utilizing the daily average net load and fluctuation coefficient. Second, a model was established for the short-term optimal operation of the cascade hydro-photovoltaic hybrid system. Then, a synchronous peak-shaving strategy of cascade hydropower stations was proposed based on the fluctuation coefficient. Finally, the framework was applied to a case study in the Qinghai Province, China. The results showed an obvious competitive relationship between the two objectives. In the hybrid system, the peak-shaving task is mainly carried out by a daily regulation hydropower station, while its base-load task is jointly carried out by runoff and daily regulation hydropower stations. When the average daily runoff is less than 30% of the hydropower rated flow, the cascade hydro-photovoltaic hybrid system should bear single-peak load on sunny, cloudy, and dusty days, otherwise, it should bear double-peak load. It should bear double-peak load under different daily average runoffs on rainy and snowy days. After the cascade hydropower relative position was interchanged, the cascade hydropower overall peak-shaving capability decreased. Thus, the above results prove the feasibility of the research framework, and it provides a reference for the short-term operation of cascade hydro-photovoltaic hybrid system.