mohammad khosroshahi

The phenomenon of dust storms has become a global environmental challenge. As a natural disaster, it has significantly affected Khuzestan province due to its geographical location and proximity to vast desert areas. This study aims to examine land management strategies to mitigate dust production in the southeastern dust source of Ahvaz by implementing effective land management techniques to control wind erosion in this region.

To conduct this research, ecological land resources—including climate, geology, soil properties, land use, vegetation cover, wind erosion, and agricultural and livestock conditions were analyzed using satellite imagery and extensive field surveys. By overlaying maps, the dust source area was classified into ecologically homogeneous units (work units). Based on the physical and chemical properties of the soil, the vegetative potential for biological stabilization was determined according to the ecological requirements of native plant species. Soil samples were collected from 106 points at three depths, and soil erodibility was assessed using a wind tunnel. A wind erosion sensitivity map was then generated to prioritize the stabilization of work units. The characteristics of erosive winds were analyzed using hourly wind speed and direction data from 21 meteorological stations. After creating a database of ecological resources in a GIS environment, the vegetative potential of the work units was evaluated using soil properties. Subsequently, specific stabilization projects were proposed for each work unit.

The findings of this study indicate that the stabilization strategy was planned systematically, considering the ecosystem type, and dust control projects were designed based on land use classifications. The land use distribution of the dust source area includes 37% rangelands, 10% bare lands, 11% dried wetlands, 24% rainfed agriculture, and 13% irrigated agriculture. The proposed projects included biological measures such as shrub planting, afforestation, roadside tree planting, and living windbreaks along farm edges, as well as management strategies such as soil moistening, leaching, irrigation, grazing control, construction of non-living windbreaks, and rainwater harvesting techniques. Analysis of the energy trend of erosive winds over the past decade revealed no significant changes. Instead, the activation of dust sources was attributed to land use changes, precipitation patterns, and drought occurrences.

The lack of water allocation to downstream ecosystems, combined with the construction of large dams and multiple watershed management structures in upstream areas, has led to the transformation of wetlands and sedimentary plains into major dust sources and has contributed to surface soil salinization. Restoring flood capacity in these areas was achieved through the construction of water supply channels to meet the water demands of biological stabilization projects and facilitate the moistening of wind erosion-sensitive units. Overall, the implementation of these projects demonstrated that this ecosystem restoration-based approach, with a focus on wind erosion-prone lands, can serve as an effective model for stabilizing the country’s dust source areas.

Dust storms affect different regions of the globe countries and Iran. The dust storm events were considered as one of the climatic components in arid and semi-arid regions and it is called one of the most important environmental problems of these regions. Therefore, in this research, the activity class of sand dunes were investigated based on the Lancaster index in Iranshahr city in Sistan and Baluchistan province. The aim of this study is to investigate the climatic different conditions on the mobility of sand dunes in Iranshahr city. Meteorological data for synoptic station of Iranshahr were collected from the Iranian Meteorological Organization for 15 years (2003 to 2018). After examining the wind speed velocity in Iranshahr, and extracting the seasonal and annual Wind rose diagrams, Dust Storm Index (DSI) was calculated.  Finally, the effects of possible changes in climatic elements on the mobility of sand dunes were predicted. The results showed a significant correlation between the Lancaster index and the amount of annual rainfall, wind and drought index. The results of the sensitivity analysis also showed that if the frequency of erosive winds and potential evaporation and transpiration increases to 30%, the activity of sand dunes in Iranshahr station increases by 25 and 23%, respectively, on the other hand, with a 30% increase in rainfall, the activity of sand dunes decreases by 30%.

The extended periods of drought, decrease in vegetation, and enlargement of the salt playa at Lake Urmia have resulted in the formation of local dust hotspots on the periphery of Lake Urmia in East Azarbaijan province. The objective of this study was to examine the spatial and temporal distribution of wind erosion in East Azarbaijan province using the DSI index. To achieve this, a set of weather data recorded over the past 30 years at specific codes in meteorological stations was compiled. Subsequently, the Mann-Kendall test was employed to assess the presence of a trend in the data series. Following this, the frequency of dust storms was calculated using the DSI index, and a spatial distribution map was generated in the GIS. The results of the Mann-Kendall test indicated that the slope of the trend for both local and extra-local dust storms in the province is on the rise. However, only the trend in extra-local dust storms is statistically significant at the 95% confidence level. The findings of the research revealed that the majority of the observed dust storms originate from outside the local area in East Azarbaijan province. Nevertheless, there has been a relative increase in the frequency of local dust storms in recent years, which can be attributed to the prolonged droughts resulting in reduced vegetation and the expansion of the playa of Lake Urmia. In this context, the highest frequency of dust storms has been observed at the Tabriz, Sahand, and Maragheh meteorological stations near Lake Urmia.

The location of the unique ecological area of ​​Hamoon in the Sistan plain has given it a special environmental importance, and according to the Ramsar Convention, the Hamoon area as an international wetland has special ecological values ​​for the world. However, neglecting the ecological water requirement has led to some natural ecosystems being seriously damaged and at the same time turning into dust sources. The need to determine the minimum water requirement of aquatic ecosystems and the regulation of environmental flows has received global attention and is one of the important challenges of water management and wetland ecosystems. Available free satellite data can reveal long-term surface water changes, improve modeling, and inform changes for water management decision-making. Using of the Google Earth Engine (GEE) platform has solved the need for speed in processing and access to various data. The use of the world surface water layer product (JRC Global Surface Water Mapping Layers), by providing the Transition band and Seasonality band which is the result of changes in water areas from 1983 to 2021, can provide a suitable base level. In order to calculate the water requirement, it should provide based areas with less time and cost. In this study, the base level of Hamoons was extracted using the mentioned product in Google Earth Engine and interpreted in ArcGIS software. Finally, the water requirement of Hamoons was calculated using the hydrological method.

In the Sistan region, located in the east of Iran, there are three main Hamoons named Pozak, Sabori and Hirmand. In order to estimate the water required for wetland restoration, using the hydrological water balance method, the water losses in one year will be compensated through precipitation and discharge. In order to estimate the pattern of wetting of the wetland area, the global surface water layer product was used in the Google Earth Engine environment.Considering that this product is derived from the changes of water zones between 1984 and 2019, it can be zoning the wetland based on the hydrological trend. First, the changes of the aqueous zone were investigated using the Transition band. Then the classes in this band were interpreted using the Seasonality band. The final map was created by merging the classes that followed the same behavior. In order to reveal the trend of the water body area of the wetland in different seasons, a number of plots were extracted from each class and the trend of the NDWI index was monitored over five years (from the beginning of 2016 to the end of 2020). Then, using the monthly long-term average (fifty years) of precipitation, evaporation and transpiration of the area, which was converted into the seasonal average, the water losses and the amount of discharge required for the stability of the water body of the wetland were estimated.

The " Permanent to Seasonal " and " Lost Permanent " classes were wet in the past and currently receive less water. Therefore, they can be first priority. At the same time, the "Seasonal" class shows the most presence of water during the year. As a result, it can be second priority. The first priority area is 993.7 square kilometers, the second priority area is 871.7 square kilometers, and the third priority area is 1370.6 square kilometers. Therefore, by merging the above-mentioned classes, the base level map for the estimation of Hamoon's water requirement was obtained. After calculating the median of NDWI index for each pixel, the 5-year trend was monitored for each zone (class of each priority). The monitoring of NDWI changes in each of the zones shows that the surface with the first priority in the period of April to August (spring and summer) and the surface with the second priority in the period of February to June (winter and spring) is wet. The surface with the third priority is often dry and in some years it is rarely wet in April (spring season). As a result, the water requirement of Hamoons with an area of ​​3237 square kilometers is equivalent to 3804 million cubic meters per year.

According to the results of this research, the water requirement of Hamoon is 3804.3 million cubic meters per year with a base area of  ​3237 square kilometers.

Using the pattern of the number of months of water presence in the wetland, which is extracted from the seasonality band, the eleven classes of the transition band were interpreted. As a result, it can be second priority. The results show that the pattern of long-term behavior of water in the Hamoon area indicates the absence of a permanent water surface in these ecosystems. Examining the trend of changes shows that the areas are wet in three seasons: spring, summer and winter. The results of this research, using the GEE product and the change of the trend of NDWI index, could help reveal the hydrological system and lead to a more realistic estimate of the ecosystem's water requirement. Perhaps the best advantage of this method compared to the traditional types of using satellite images, in addition to spending less time, is a more comprehensive view of the unique changes of each water zone compared to other zones. In fact, using the time series of images helps to plan for each water area according to its nature and will prevent prejudice and repetition of a fixed pattern. Estimating water requirement along with its seasonal distribution, can help managers and policy makers to demand the required amount of water and increase productivity by managing water distribution.

Wind erosion and dust phenomenon are considered as one of the important processes of land degradation and a serious challenge in Iran. This phenomenon occurs due to the interaction between weather and terrestrial processes. The purpose of this research is to investigate and analyze the trend of temporal and spatial changes in the number of dusty days in Iran and to investigate the role of climate in its spread.

In this research, after receiving hourly and daily statistics of dust events (through 148 synoptic and climatology stations) and parameters of precipitation, evaporation, temperature as key climatic elements (from 171 stations) in 22 provinces located in arid and semi-arid regions of Iran, The spread of dust was investigated and the correlation between climate and dust was determined. After calculating the number of dust days in Iran, the information was called in the GIS environment and a map of the spatial changes of the parameter of the number of dust days in the three decades of 1987-1996, 1997-2006, 2007-2016 was prepared. In the following, the spatial analysis of this parameter and its expansion over three decades were investigated. Next, the climate parameter that had the highest correlation with the number of dusty days was selected and after preparing a map of its spatial changes in the GIS software environment, the spatial compatibility of the desired parameter with the expansion of the number of dusty days was investigated. In the next step, after performing the homogeneity test on the dust occurrences, the partial square regression model was used to determine the contribution of the three mentioned climatic elements as independent variables and the number of dust days as a dependent variable.

The results showed that the number of dusty days and the area of its occurrence have increased in Iran, so that in the last decade under study (2007-2016) compared to the previous two decades, the dustiest event occurred in Iran. This increase has been more intense especially in the western and southwestern regions of the country, which were also affected by extra-local dust events. These dust events have spread to the central regions of the country with greater frequency. The homogeneity test in many provinces showed a common change point (year 2007-2008) in the number of dusty days, which could be related to the beginning of severe droughts and climate changes from this year in Iran. The study of climatic parameters (temperature, precipitation and evaporation) on changes in the number of dust days in Iran showed that during recent years, temperature had the highest significant correlation level (0.58) with the occurrence of dust. The temperature gradient map in the last decade (2007-2016) compared to the previous decade (1997-2006) also showed the increasing trend of temperature, especially in the western and southwestern regions as well as the southeastern regions of Iran. Modeling the effect of climatic parameters of temperature, precipitation and evaporation on the parameter of the number of dusty days showed that the contribution of the studied climatic parameters to the occurrence of dusty days is about 33% and other effects can be related to things such as human factors or soil characteristics, type of vegetation, solar radiation, etc.

In general, the results of examining the trend of changes in the number of dust days and climatic indicators for nearly 3 decades indicate a significant increase in the number of dust days in most parts of Iran and the conditions for this increase have been provided and if the trend of changing these indicators in the coming years is according to the current trend, the risk of environmental problems in the country can be expected to increase.

 The history of using American mesquite (Prosopis juliflora) for desertification control especially sand stabilization in Iran, is long. Considering the non-native nature of this species, attention should be paid to its ecological requirements, especially water needs or evapotranspiration (ET). This can contribute to the sustainability of sand stabilization programs and fine dust control and play an influential role in ecosystem development. Determining plants' evapotranspiration rates through lysimetry is one of the most accurate direct measurement methods. 

 The experiment using weighing and drainage lysimeters began in 2021 by planting seedlings inside lysimeters located at the Yazd Shahid Sadoughi Desert Research Station. It continued for two years. Nine lysimeters with a volume of 1.95 m³ (height: 170 cm, diameter: 121 cm) and a surface area of 1.15 m² were used. The ET rates and the crop coefficient (Kc) of Prosopis juliflora were studied under different soil moisture levels, including field capacity (no stress), 67% of field capacity (mild stress), and 34% of field capacity (severe) for various growth stages. Irrigation was performed by drip irrigation based on a fraction of field capacity with an appropriate number of droppers calculated for each treatment. For field capacity, 67% and 34% of field capacity treatments, 6, 4, and 2 droppers with an 8 liters per hour flow rate were used, respectively. Each treatment was irrigated twice with the appropriate amount of water based on soil moisture levels. 

 The results showed that Prosopis juliflora, under lysimeter conditions and the local climate, had an annual ET rate of 496.5 mm and a Kc 0.21. These values for the 67% and 34% field capacity treatments were 445.4 mm with Kc 0.18 and 275.2 mm with Kc 0.11, respectively. The ET rates of Prosopis juliflora at different growth stages revealed that the highest ET occurred during the development period of 124 days. This corresponds to rapid shoot, branch, and leaf growth. The ET rates in different irrigation regimes for field capacity, 67%, and 34% of soil moisture were 322.1 mm, 281.7 mm, and 158.3 mm, respectively. The lowest ET rate was associated with the final growth stage. The Kc for various growth stages in the field capacity treatment were 0.19, 0.24, and 0.14 for the first, second, and third growth periods, respectively. Under these conditions, a sigmoid growth curve (initial growth, development, and end of growth) can be defined for this plant. 

 It is recommended for afforestation with this species in Iran's southern regions, considering its optimal planting density to reduce competition. It is also recommended to pay attention to its ET rate, especially during the hot months of the year when it can exceed 2.5 mm per day. By examining and calculating the ET rates of mature trees with appropriate efficiency in sand stabilization and dust control, it was found that to create a canopy cover area, as mentioned, it is necessary to have 4846 m3 of water per hectare (equivalent to 484.6 mm per year) available to the plant. In other words, with this amount of ET, the plant can expand its canopy cover area to 19.5 m2 and, with 155 individuals per hectare (8×8 meters), cover 30% of the area, which is suitable for sand stabilization.

Research has been done on different materials to control and reduce wind erosion. Among them, we can mention the performance of agar gum biopolymer in reducing dust production at different concentrations of 0.5, 1.0, and 1.5%. Its results showed that the addition of biopolymer improves the water-holding capacity, increases the surface and compressive strength of the soil, and decreases dust production. In another study, agar gum biopolymer significantly improved soil mechanical properties. This study investigates the effect of polymer nuclei (M19) on controlling sand dunes. This research investigates the effect of nucleos (M19) mulch on reducing wind erosion and controlling sand dunes and dust.

This research was carried out in Segazi Plain, a study and implementation priority due to its proximity to urban areas, military facilities, transportation, as well as industries and workshops located there, from the aspect of preventing wind erosion and desertification. After choosing the field, two plots of 500 square meters with the same conditions (an active hill with an area around it with natural and hand-planted vegetation) were selected. To determine the effect of soil cover, the area of each plot was determined by wooden stakes. In addition, the surrounding sand dunes were staked to measure their displacement. A pump sprayer mulched the measuring plot with nucleos (M19) mulch. Following the soil moisture changes, information including seedling survival and growth rate, soil cover's ability to control sand dune displacement, and compressive stress was examined during different months. Finally, the effectiveness of soil cover was compared with the control treatment using the T-test.

 The results of examining the changes in humidity and the effect of soil cover on it showed that the highest humidity in the area was after rain. No clear difference was observed between the drying process of the control plot and the mulched plot. It was also found that this mulch positively affects seedling growth rates. During the research period, the control sand dunes moved about 0.75 to 2.5 meters depending on the season and wind direction. In contrast, the mulched sand dunes remained stable. On the other hand, with time, the mulched field's surface became flaky, and signs of wear and tear were observed.

The first point about using this polymer as a soil cover is its two phases during transportation and storage until mulching. In such a way, the two layers can be clearly distinguished. As a result, mixing is necessary for the uniformity of the polymer during the preparation of the final emulsion. This can be considered as one of the negative characteristics of the used polymer. This mulch positively affected soil moisture changes and increased soil moisture retention. On the other hand, the comparison of the growth of the seedlings in the mulched field and control also shows its effect on the growth of the seedlings. This soil cover's only positive and critical feature is its high flexibility after mulching in such a way that it is possible to drive on it with caution. Finally, after a year, cracks were first detected in the research field. Gradually, the number and depth of cracks increased, which caused the mulched field surface to become flaky. Following this complication, instability and signs of wear and tear were observed in the mulched area. However, no movement or change in location was observed in the mulched hill. It should be noted that with time, more destruction occurs on the surface of the mulched area. Following more flaking, the mulched surface may be destroyed, and hill erosion may begin. Considering these cases, mulching in this and similar areas is not recommended.

One of the problems in the field of biological restoration of the wetlands of deserts is the lack of diversity of species compatible with existing conditions and how establishment. Natural potential of moist margin of salt lake in Kashan during a research project entitled "Geochemistry and vegetation cover characteristics of Iranian wetland margins for their biological recovery (identification of habitat potential)" were identified and were zoned areas with different salinity and groundwater levels. Using the information of the above design, in order to enrich the species diversity and biological regeneration of the wet margin of salt lake, the establishment of 6 species of Suaeda fruticosa, Halostachys caspica, Atriplex halimus, Salsola imbricata, Halocnemum strobilaceum, Aeluropus littoralis, based on Complete randomized blocks were studied under species in 3 replicates. In this regard, after collecting the seeds of above mentioned species and determining the genus, they cultivate at the arid and desert areas research station of Kashan, and then cultivate according to the plan of the project implementation. The main trait was evaluated for survival percentage, but traits such as height and diameter of the canopy were also measured during the 5 years of the project. The results were analyzed in SPSS environment and it was determined that H.strobilaceum, S.fruticosa, H.caspica, S.imbricata were 5.67, 5.11, 5.56 and 4.9, each with the highest survival has been implementing the plan for the last 5 years. Considering the high nutritional value and favorable palatability for the camel, it is recommended to cultivate in the wet margin of the salt lake for prevent wind erosion and dust.

Land cover change has become one of the most challenges due to the interaction of negative effects of climate change with human activities. In this study, land cover changes in the Hendijan Basin with a focus on the impact on dust sources located in Khuzestan province were investigated. Areas of forests, rangelands, woodlands, water, agricultural lands, residential and barren lands were extracted during 30 years at 1987 and 2017 using Landsat image processing. Dust sources located in Khuzestan have been monitored and land cover changes in have been revealed. The results show that trend of land cover changes inside and outside Khuzestan province is different from each other. In fact, the highest rate of change compared to beginning of study is occurred in mountainous part of the Hindijan Basin is due to increasing lakes of dams (9.7 times) and in the plain part due to the expansion of residential lands and also increasing cultivated area (8 and 4.9 times). Also, 936.31 square kilometers, has been added to barren lands, at the same time, the area of rangelands and forests has decreased 367.60 and 2633.40 square kilometers, respectively. Detection of changes in Khuzestan dust sources shows that the east and southeast area of Ahvaz, which was covered with vegetation and water (seasonal floods and flood plains) in winter of 1366, has become barren land in 1396. Monitoring land cover changes and reporting results helps managers make more informed decisions.

As one of the most significant and sensitive landforms to wind erosion, sand dunes vary in their extent of activities based on the influence exerted on them by various climatic and terrestrial factors.The study area comprises a Busher province’s county located in southern Iran, where sand dunes activity causes great problems for the local community. Therefore, the identification of active sand dunes by using wind regime of the region and the factors involved in their activity based on the Lancaster index, the aim of this research is.

First, the trends of climate factors, including precipitation, temperature, potential evapotranspiration, wind velocity, and local and non-local-originated dust were investigated at an annual scale using the data concerning the hourly-based wind velocity, weather codes, monthly precipitation, temperature, and potential evapotranspiration data collected from Dayer meteorological station over a 30-year period (1989–2018). Then, the sand dunes’ mobility status was examined by calculating the frequency of erosive wind and the aridity index over the whole study period using the Lancaster Index. Moreover, Sensitivity analysis was performed to predict the effect of meteorological parameters’ potential changes on sand dunes' mobility.

The study’s results indicated that according to the Lancaster index, sand dunes were fully active during the 30-year period. Furthermore, the aridity index was found to be subjected to real, extremely serious, and serious risks of desertification in three classes hyper-arid, arid, and semi-arid, respectively. On the other hand, the results of sensitivity analysis suggested that if the frequency of upper-erosive-threshold winds would increase by 30% in the future, the sand dunes' activity and mobility would increase by 30 %. However, if the precipitation rate increases by 30 %, sand dunes' mobility, and activity will decrease by 23%. Moreover, no significant trend was observed in meteorological parameters, including precipitation, temperature, and potential evapotranspiration throughout the whole study period.

In general, an increasing trend was found in sand dunes activity during the 30-year study period, suggesting a direct correlation between such an increase and precipitation. Moreover, the study’s results indicated that the management measures carried out over the past 30 years (for instance, planting seedlings, hand-planting afforestation, and grazing management) have proved insufficient, necessitating the application of new management policies in this regard.

Long-term monitoring as well as the impacts of climate change on sand dune mobility play a crucial role in reducing their adverse effects, including creating dusty days, potential risks of reduced air quality, and other environmental and health risks. The main objectives of this study were to investigate the dust phenomenon and its origin, to analyze the mobility status of sand dunes using two indicators, to determine the effect of climatic conditions on mobility, and also to predict the effects of changes in climate parameters on sand dunes mobility in the strategic area of ​​Sarakhs, located on the northeastern border of the country, for a period of 27 years. The results on the number of dusty days showed that the local dust events at Sarakhs station had a significant increasing trend. The results of sand dune mobility using Lancaster and modified Lancaster indices showed that there was a significant relationship at 99% level with dusty days, based on which the ability to use the modified Lancaster index in this area is raised. It can also be acknowledged that in the study region, increasing environmental drought coming with the mobility of sand dunes increases the risk of desertification. Also, the results of sand mobility sensitivity analysis showed that the combined effect of the frequency of erosive winds or the potential of sand transport and evapotranspiration has the greatest effect on reducing and increasing sand activity in the future.

This study was conducted to investigate the effect of drought on dust events in different cities of Qazvin province. Rainfall and temperature data were used to calculate the standardized precipitation-evapotranspiration index (SPEI) and three-hourly dust events data were used to calculate the number of dusty days in the study stations. Based on the Spearman correlation coefficient, the impact of dust events on the drought phenomenon was investigated by considering different time delays. The maximum correlation between SPEI and the number of dusty days in Ghazvin city without considering the time delay of -0.38 and at the level of 99%, was significant, indicating the simultaneous impact of dust events from the drought phenomenon in the center of the province. The results also showed that the response time of dust events to meteorological drought with a delay of one year in Moallem Kalayeh city is significant at 90% confidence level (r = -0.52). Meanwhile, in other cities of Ghazvin province, no significant relationship was observed between the two phenomena of dust occurrence and meteorological drought.

The purpose of this study is to evaluate the effect of climate change on the occurrence of dust in Ghazvin province. In order to study climate fluctuations, average rainfall parameters, relative humidity, potential evapotranspiration, temperature, relative humidity, average wind speed and wind speeds greater than 6 m / s in the period 2006-2016 were considered and the number of dusty days was extracted according to the dust phenomenon codes (06 to 09, 30 to 35, and 98)and calculated on a monthly, seasonal and annual scales. The trend of changes in climatic parameters and the number of dusty days were investigated using Mann-Kendall test and the relationship them between was investigated using Pearson correlation coefficient. The results showed that wind speeds of more than 6 m / s in most study scales had a significant decreasing trend (Z> -1.96). A similar trend was observed for mean air temperature and potential evapotranspiration in October. The trend of changes in dusty days was shown to be significant for internal events in summer and for extranal events in spring. However, no significant changes were observed in other parameters. The results also showed that local dusty days with a slope of 0.08 and days with extenal scource dust with a slope of 0.68 in the statistical period have increased. Pearson correlation analysis showed that there was a strong and significant relationship between the increase in mean maximum temperature with the number of days with local dust in winter and also between the average speed of spring surface winds with the number of dusty days during this period (r=0.67; p-value≤ 0.0.5).

The destructive phenomenon of desertification, in addition to land degradation, and causing environmental problems and dust events, exert great damages to human societies such as damage to transmission lines, and blockage of roads and railways. Various mechanical, chemical, and biological methods have been proposed to deal with desertification. Recently, in different parts of the world and some parts of Iran, biological soil crusts have been used as biological improvers to modify and stabilize the soil against desertification. Biocrusts consits of a collection of lichens, mosses, algae, fungi, bacteria, and cyanobacteria that play a major role in soil regeneration, increasing desert ecosystem performance, and combating desertification. Researchers have identified the addition of cyanobacteria to the soil as an effective way to improve soil and increase soil ecosystem performance, especially in desert areas. For this purpose, cyanobacteria are used alone or in combination with plant cultivation.

The study area is part of the Sejzi Desert (Central Deserts of Iran) which is located in Isfahan province of Iran. Wind erosion threshold speed was measured in Sajzi plain using a portable wind tunnel. After plotting the storm rose by the data obtained from the synoptic station of Shahid Beheshti Airport in a period of 25 years from 1991 to 2016 by using WR Plot 7 software in different seasons, the speed and frequency of winds were determined. For conducting the intended experiments, 4 soil samples were collected from the area with biocrust cover and 4 other samples from the area without biocrust cover. PH, EC, OC, saturated moisture content, MWD, dry grain size distribution and soil texture were measured for soil samples. Carbohydrate monomers were identified by HPLC. For the culture of cyanobacteria, very small pieces of soil undercovered with cyanolichens were placed on BG 11 medium, and the processes of isolation, culture, and purification were done, respectively. After sieving the soil through a 4.75 mm, the wind tunnel trays in the dimensions of 30 x 50 x 8 cm with an area of 1500 cm2 were filled with soil and their surface was smoothed. The control trays were also saturated to a depth of one centimeter with a distilled water. The amplified cyanobacteria were then isolated from the culture medium under a BX51 light microscope and prepared in a water solution with a biomass weight of 2.5 g/l by inoculated water method and in the required amount according to the pore volume and were sprayed on soil samples. Mass fluxes were measured for all soil classes at different wind speeds according to the erosion threshold speed between 7.15 to 15.06 m/s. Shear strength and soil moisture were also measured. Experiments were performed completely in a randomized design in three replications.

The wind erosion threshold in the center of the Sejzi plain was 3.76 m/s on the sandy loam soil texture. Most wind erosion occurs in late winter and early spring. In spring, 35.8%, and in winter, 21.9% of winds had a speed of 7-11 m/s. The EC, sand, and silt were lower, in the soil undercovered biocrusts, but saturation moisture, MWD, clay, and OC were higher. Of the four identified monosaccharides, arabinose was found in all three samples, but its amount was different in soil samples. Also, Mannose and Xylose were identified and measured in only one of the soil samples at 0.01% and 0.02%, respectively. Based on morphological characteristics, two specimens of cyanobacteria including Microcoleus vaginatus and Coleofasciculus chthonoplastes were identified. In samples treated with carbohydrates, there was no change of mass fluxes and threshold velocity of wind erosion, and shear strength with control samples. According to the results of the ANOVA test, the mean winding at different wind speeds was affected by soil moisture and texture and treatment with cyanobacteria. By speed of 7.15 and 15.06 m/s, mass fluxes had a significant relationship with cyanobacterial treatment and soil texture. At 11.21 m/s, sediment yield values were affected by texture classes and soil moisture content and had no significant relationship with cyanobacterial treatment. The results showed that the addition of cyanobacteria to the soil increases the shear strength of the soil against the wind force. Texture type and soil moisture percentage had no significant relationship with shear strength values.

The central parts of the Sejzi plain were sensitive to wind erosion in terms of soil characteristics and compared to its peripheral strip, wind erosion was more intense and had destroyed the plain soil. The presence of microorganisms in the soil and its successive proliferation increases the organic content of the soil and increase soil stability, while adding a certain amount of carbohydrates artificially in the soil surface layer, especially in natural resources, leads to their decomposition by environmental conditions and climates such as ultraviolet rays and their function in the soil is reduced and may even stop. Cyanobacteria are better established in loam and silty loam soils than other types of soil and this has affected the soil loss flux, but due to the sensitivity of particles smaller than 0.84 mm to wind erosion of more particles at a speed of 11.21 m/s, cyanobacterial treatment was significant. The difference between the samples treated with cyanobacteria was due to the resistance of fine particles between the filaments of cyanobacteria Microcoleus vaginatus and Coleofasciculus chthonoplastes. According to the USDA classification, the range of soil particles for Fine Sand and Very Fine Sand varies from 0.25 to 0.05 mm and are suitable for stabilization with Microcoleus vaginatus and Coleofasciculus chthonoplastes cyanobacteria.

Drought and dust are serious atmospheric hazards that have affected the western and southwestern parts of Iran in recent years due to various reasons. Since numerous droughts have had a detectable impact on occurrence and severity of dust, therefore, related studies are considered important. The purpose of this study is to analysis the trend of dust storms frequency and its relationship with drought (SPEI).

Bushehr province is located in ​​ north of the Persian Gulf and southwest of Iran. To investigate the effect of drought on dust storm, data on the dust events at daily timescale, monthly precipitation, temperature, humidity-relative, evapotranspiration data were utilized from 7 synoptic stations over 30 years (1989–2018).The Standardized Precipitation  Evapotranspiration Index (SPEI), dust storm occurrence based on weather codes 06 and 07 events and linear regression of parametric statistical test were used to estimate of drought, dust storm index (DSI) and their trends were analyzed by parametric linear regression test method. Spatial distribution of drought and dust in the case study obtained in Arc GIS software by IDW method. To investigate the relationship between climate and dust storms, the data of stations with significant trend of drought and dust storms frequency were analyzed using linear regression.   

The results showed that the percentage of drought frequency were classified into mild drought (79.06%), moderate drought (18.96%) and severe drought (2%) in the whole 30 years. Approximately 6.25% of droughts is occurred in the first decade, 50% in the second decade and 43.75% in the third decade. The spatial distribution map of drought also showed that the main focus of this phenomenon is occurred in the southern, central and northeastern parts of Bushehr province than rest of other parts. Existence air currents from Arabian Desert towards the central area of the province, the lack of appropriate vegetation, soil erosion and sand and salt zones in these parts have confirmed this issue. The percentage of occurrence of different drought during the whole study period showed that the occurrence of mild droughts was more than moderate droughts and the occurrence of moderate droughts was more than severe droughts. The overall trend of DSI changes across the entire study duration was decreased.

This study showed that dust storm index with increasing drought intensity was decreased and its correlation with drought during the 30-year period was not significant. Overlaying both of spatial distribution maps of drought and DSI did not show homogenous distribution pattern. This indicates that human factors or external source of dust can play a more important role in creating heterogeneous distribution pattern of drought and DSI in Bushehr province. Finally, the relationship between drought and DSI has always fluctuated according to dry and wet years over the whole study period.

Climatic components are the vital factors influencing the dust event. It was believed that changes in climate parameters play a crucial role in the occurrence of dust events. Former studies have shown that temperature, rainfall, and wind speed contribute to poor vegetation, providing requirements of dust events. Long-term dust data indicated that climate has a profound effect on dust events and the occurrence of dust storms compared to the desertification process (Zhang and Anastasio, 2003). Monitoring Iran’s meteorological data indicates changes in precipitation and temperature in the last two decades (Rezaei and Ghasemieh, 2019). Alterations in the amount and pattern of rainfall and rising temperature can initiate the changes that cause natural hazards, including dust storms. Hence, in the present study, the trend of changes in climatic parameters in Khorasan Razavi province has been investigated. Note that the climatic parameters are consisting of rainfall, average temperature, wind speed, and frequency of erosive winds.

 According to the objectives of the present study, the monthly precipitation, temperature, and wind speed of seven synoptic stations including, Mashhad, Sabzevar, Sarakhs, Neishabour, Torbat Heydariyeh, Kashmar, and Quchan, were obtained from the meteorological organization of Khorasan Razavi from 1990 to 2016. Hourly dust codes also were extracted to detect the number of dusty days in the study period. The relationship between climatic parameters of precipitation, temperature, wind speed, and erosive wind frequency was inspected by the Pearson correlation coefficient for each station. Later, the trend of dust events and climatic parameters was analyzed using the Mann-Kendall trend test.

 Results of dust codes indicated the local origin for the highest frequency of dusty days. Even though Sarakhs and Mashhad stations had the highest dusty days, Quchan and Kashmar had the lowest one in the study region. The Mann- Kendall test pointed out an increase in temperature for all study stations except Neishabour. Meanwhile, the precipitation had a downward trend in the Mashhad, Kashmar, Sabzevar, Torbat Heydariyeh, and Sarakhs stations and an increasing trend in the Neishabour and Quchan. Raising the frequency of the erosive wind in Quchan, Kashmar, Sabzevar, Sarakhs, and Neishabour stations during the study period could also be stated. In most of the stations (except Mashhad and Neishabour) upward tendency in the number of dusty days is consistent with other researchers such as Mehrshahiand Nekounam (2009) in Sabzevar, Boochani, and Fazeli (2011) in Ilam, Shahsavani et al. (2011) in Khuzestan stated. Hence, the decreasing tendency of dusty days in Mashhad and Neishabour is also in line with Rafiei et al. (2015) in Yazd, Semnan, Kashan, Ramsar, and several other stations. The falling trend of wind speed in Mashhad station can be reflected as the main reason for the reduction of dust events. In addition, the rising tendency of precipitation and possible decline of drought in Neishabour can be considered as the main reasons for the decrease in the number of dusty days. To understand the effect of climatic factors on the occurrence and intensification of dust events, the relationship between the number of dusty days and climatic parameters was determined. The results of correlation analysis between dust events and climatic parameters showed that the temperature directly affects the dust events in all stations except Mashhad. The positive correlation between temperature and dust events was stated in other studies (Bahrami et al., 2013; Amgalan et al., 2017). The correlation coefficient between dust event and precipitation showed a negative relationship between them which was significant at 95% level in Sarakhs station. Other studies (Ali et al., 2016; Broomandi et al., 2017; Amgalan et al., 2017) have also indicated the inverse effect of precipitation on dust events, which is following the findings of this study. The results of correlation analysis between the number of dusty days and wind speed and the frequency of erosive wind showed that the enormous influence on dust events is wind speed. While, at Neishabour station, there is a significant negative relationship between dust and wind speed. Indeed, the inverse relationship between dust and wind speed indicates that with increasing wind speed, the dust emission does not increase and another factor reduces the effect of wind speed. As Kimura (2012) reported the impact of vegetation on reducing the wind speed impact on the dust occurrence.

 It was proven that the number of dusty days is in line with the variations of the climatic parameters. The decrease in rainfall, increase in temperature, and wind speed has been accompanied by an increase in dusty days in the region. In general, correlation analysis of dusty days and climatic parameters in Khorasan Razavi province indicated that wind speed and the frequency of erosive wind have considerable influence on dust events. However, the effect of wind speed on dust events at the Neishabour station reflected the significance of vegetation cover on reducing the transfer of soil particles.

Drought is a long-term natural phenomenon when the average precipitation rate is less than that of the normal periods. As a natural phenomenon, drought has turned into a  natural disaster occurring throughout Iran in recent decades with all its associated consequences. On the other hand, although rainfall is considered as the main indicator of water availability, the temperature is also an important factor in this regard, as it controls the evapotranspiration rate. Therefore, parameters such as precipitation and temperature can be used as indicators for analyzing the drought. Moreover, identifying drought trends based on previously recorded data, noting their occurrence in different times and places, and studying their variation over time play a significant role in managing water resources. It should be noted that the purpose of trend analysis is to determine the decreasing or increasing nature of trends in a series of observations performed for a random variable over time.

The Standardized Precipitation Evapotranspiration Index (SPEI) is a meteorological drought index that considers the variability of both precipitation and temperature in predicting drought conditions in a region. Enjoying a multi-scale ability to monitor and analyze drought in different scientific disciplines, the index fulfills the requirements of a drought index, being recently used in a variety of drought analyses. This study measured SPEI using precipitation and temperature data from eleven meteorological stations in Sistan and Baluchestan Province, Iran, during the study period.  The Drought events were then identified via the Standardized Precipitation Evapotranspiration Index over both 3 and 12-month timescales. The total geographical area of Sistan and Baluchestan Province is approximately 187,000 km2, located at 25° 03 N to 31° 28 N (latitudes), and 58° 47 E to 63° 19 E (longitudes). The province has an arid and semiarid climate with a mean annual rainfall of about 100 mm. The monthly precipitation and temperature data recorded at the stations were obtained from the Sistan and Baluchestan's Meteorological Organization. One of the commonly used tools for detecting changes in climatic and hydrologic time series is trend analysis. Mann-Kendall is a non-parametric trend test commonly used to assess the significance of trends in time series. This study used both nonparametric trend tests (Mann-Kendall) and graphical Mann-Kendall model trend analysis (statistical significance at 95% confidence level) to explore the drought trends in each station. The purpose of trend analysis is to determine whether the time series of a random variable's observations generally increases or decreases over time. While parametric trend tests are more powerful, it is non-parametric trend tests are widely used, as they can accommodate outliers in the data and require independent data.

The study's results indicated no negative trend in precipitation but revealed a significant trend in temperature. The SPEI values measured for the short-term time scale (SPEI 3) showed a statistically significant downward trend for all stations, which corroborates the occurrence of more critical drought periods in recent years. Moreover, the study of the frequency of drought occurrence in the stations during 10-year periods suggested an increasing trend in the occurrence of drought in recent years. As for the maximum drought index, it could be said that the index's value has typically increased in recent years, that is, more severe droughts have occurred. According to the results, the most severe drought belonged to the Khash station, and the wettest period was found in the Chabahar station.

This study sought to identify possible drought trends in Sistan and Baluchestan province using the Mann-Kendall test, considering the fact that detecting such changes offer valuable information for future water resources management. Accordingly, the analysis of previous drought events showed that more severe droughts are expected to occur in the years to come. Although this study did not seek to find possible causes of decreasing trends, the results presented herein could be used as a benchmark for further analysis of the consequences of climate change. It could be argued that low precipitation and high potential evapotranspiration (PET), especially the PET caused by rising temperature, are the main factors that could influence drought in the future. Therefore, the influence of the PET should not be ignored in drought analysis, and it is suggested that more comparative studies of different drought indices be conducted on analyzing future climate change-induced droughts.

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

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

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

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

Wind erosion and dust are two different aspects of the same situation. They are the consequences of desertification, which their harmful effects in terms of health, environment and economy have become one of the important regional and global challenges especially in arid and desert areas. In this regards, Iran and especially Kerman province have highly suffered from them. Therefore in this study, we investigated the seasonal wind regime and analysis of the frequency, speed and direction of dust-producing and erosive winds of internal and external origin. The purpose of the study is to apply the results in programs and operations to combat desertification and reduce dust events by emphasizing their possible origin at the local and regional level for authorities. For this purpose, hourly data of wind speed and direction and dust codes recorded in six synoptic stations during the years 1986 to 2016 were analyzed. Graphical study of the speed and direction of general and dusty winds was drawn using WR Plot View 8.0.2 software. The possible sources of dust in the province and the beyond were identified by identifying and analyzing the speed and direction of internal and external erosive and non-erosive winds. The correlation between them as well as investigating the satellite images of dust events were examined. Finally, the monthly wind calendar regarding dust control was presented in three management levels of regional, provincial and local. The analysis of seasonal wind direction showed that in Kerman province, the prevailing winds in the northern parts blow from north and northwestern directions;, in central parts blow from west; and in southern part blow from southwest directions. The winds from southwest and west have faster speed. The results of homogeneity test in all stations showed that the average speed of internal dusty wind had a decreasing trend during the studied years and the speed of internal wind is 2.3 times greater than external winds and the cities of Bam and Anar are more affected by regional winds than other cities. This shows that the role of northern winds to transfer of particulate matter from neighboring provinces and remote areas to the province is greater. The result also showed 97.9% of internal events occurred as a dust event and the rest (2.1%) as a dust storm. Furthermore, in all stations, prevailing and vice-prevailing winds increased their frequency and speed due to atmospheric instabilities and local thermal cyclones and increasing the slope of the pressure gradient due to seasonal changes and solar radiation that caused dust events. In this regards, the winds with an average class speed of 6-10 meters per second had the highest frequency. Based on the correlations and satellite images, the possible sources of external dusts with a wind speed lower and greater than 6 m/s were identified outside and inside of the province, respectively. These types of winds should be considered for the management of fine dust control at the regional, provincial and local levels.

The climate change consequences are more severe in semi-arid regions in the form of drought, desertification, and dust occurrence. The purpose of this study was to investigate the effects of climatic changes on dust occurrence and sand mobility in Kermanshah province, Iran.

The meteorological stations from 1992 to 2017 were selected within Kermanshah province. The trend of climate changes was analyzed by using the Mann-Kendall model. Furthermore, the dust storm index (DSI) method was used to study the frequency and severity of dust phenomenon.

The results explored that the highest precipitation is occurred in March and November in this province. DSI index was found higher value in Islamabad, Kermanshah, and Kangavar than that other station, mainly in the west of the province, occurring in in 2008 and the lowest values were in 2010 and 2013. The average wind speed was 4.6 ms-1, while the highest winds with more than 6 ms-1 speed and dominant west and southwest directions are occurred in the western part of the province. Consequently, the annual dust rose was western. Furthermore, the highest amount of dust with 175 days occurred in Saprobe Zahab (west of the province), which was mostly related to spring and summer seasons. Lancaster index explored that the sand mobility potential was prevalent in the southwestern (along to Iraq border)

The dust incidence is affected by climate change. Thus, maintaining vegetation and controlling land use change is essential management approach to adapting climate change in this region.

Drought is one of the most important natural disasters that threaten human societies. Various indices are employed for drought monitoring. The purpose of this study is to evaluate and monitor the drought phenomenon based on two indicators of standardized precipitation (SPI) and standardized precipitation-evapotranspiration (SPEI) in Hormozgan province. SPI index is calculated only based on precipitation data, and SPEI index is calculated based on precipitation data and evapotranspiration potential values Torrent White method) of drought. For this study, monthly precipitation data and average monthly temperature data of five synoptic stations of Bandar Abbas, Bandar Lengeh, Hajiabad, Minab, and Bandar Jask for a period of 30 years (1988-2017) were used. The results showed that although the values of SPI and SPEI index were correlated, SPEI index was more sensitive to drought and faster response to it and showed longer dry and wet periods. Comparison of SPI index values of different climate stations revealed no significant difference between their SPI values. It was also found that there was no considerable difference between SPEI index values for selected stations. Finally, the findings showed that the spatial distribution of the SPI index was more uniform compared to that of the SPEI index in Hormozgan province.

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