sakineh lotfinasabasl

Land subsidence, primarily caused by excessive groundwater extraction, constitutes the most advanced and irreversible stage of desertification and land degradation. While this phenomenon poses a significant threat to numerous plains and major urban centers across Iran, existing desertification assessment models have largely overlooked subsidence rates and the agricultural sector's substantial groundwater consumption. This study evaluates desertification intensity in the Qaraqom basin through the dual lenses of water resource utilization and land subsidence dynamics.

The study employed the Inverse Distance Weighting (IDW) method in GIS 10.8 to create zonation maps for three critical groundwater indices: electrical conductivity (EC), sodium adsorption ratio (SAR), and groundwater level decline. Data from 273 observation wells (2001-2018) were classified into four desertification intensity categories (low, moderate, severe, and very severe). These maps were integrated with a land subsidence rate map (2015-2016 water year) derived from Sentinel-1 satellite imagery provided by the Geological Survey of Iran. Additionally, reservoir volume changes (1985-2018) were analyzed for each aquifer to assess their relationship with subsidence patterns.

Analysis revealed severe to very severe desertification across 46.6% of the basin based on EC values, while SAR indicated low degradation in 90.6% of the area. Groundwater depletion showed the most critical conditions, with 53.4% of the basin experiencing severe to very severe impacts, particularly in the Sarakhs, Fariman-Torbat Jam, southwest Mashhad, and Narimani aquifers. Subsidence rates reached severe levels in 18.1% of the basin, with maximum values observed in the Mashhad, Fariman-Torbat Jam, Taybad, and Karat aquifers. The Mashhad aquifer demonstrated the highest subsidence rates and the most significant reservoir volume changes. Integrated assessment of groundwater and subsidence criteria classified 55.9% of the Qara Qom watershed as moderately affected and 26.1% as low-intensity desertification.

As agriculture represents the dominant water consumer in the basin, immediate implementation of water efficiency and productivity measures in this sector is crucial to prevent irreversible socio-economic and ecological consequences of ongoing desertification and land degradation.

Severe droughts and catastrophic floods are major challenges resulting from climate change in the Zagros forest ecosystem. Climatic anomalies such as heat waves and prolonged droughts can create favorable conditions for pest and disease outbreaks, leading to the decline of oak forests. The Zagros oak forests are situated in semi-humid and semi-arid climatic zones and, due to their location in the global dry belt, frequently experience recurrent droughts. The biodiversity and ecological role of these forests, acting as a protective belt and natural barrier, highlight their significance. Spanning 11 provinces and covering an area of 6 million hectares—accounting for 40% of Iran’s forests—the management and planning of this ecosystem is highly complex due to its vast extent and the influence of various environmental factors. Identifying areas that experience more frequent, prolonged, and severe droughts can help forest managers mitigate damage and enhance adaptation to current and future climate changes.

To assess drought occurrence in the Zagros ecosystem, the Standardized Precipitation Index (SPI) was utilized to analyze the temporal distribution of drought frequency, duration, and severity over a 28-year period across three selected stations in northern, central, and southern Zagros. Based on regional conditions and classifications from Iran’s National Drought Center, the SPI was categorized into nine classes. The index was calculated for synoptic stations with a 28-year statistical record at 3-, 6-, and 12-month timescales using ClimPACT software. Given the vast study area, the Zagros region was divided into three sections (northern, central, and southern), and drought severity and duration were visualized through graphical representations. After evaluating drought intensity, duration, and frequency across all stations with more than 28 years of data, the percentage of drought-affected areas was calculated for the entire Zagros ecosystem over a common statistical period (1992–2019). The spatial distribution of drought severity during peak drought years was mapped using the ordinary kriging method in ArcGIS software. By identifying years when widespread drought affected the entire Zagros, regions experiencing severe and extreme droughts were classified as critical zones for conservation and research efforts.

The findings indicate no significant difference in drought severity across northern, central, and southern Zagros; however, the timing of the most severe drought events varies. Across all timescales, the longest drought period occurred between 1999 and 2001, coinciding with the onset of forest decline in the Zagros. Notably, from 2007 to 2017, more than 40% of the Zagros region experienced prolonged drought. While droughts can extend over hundreds of kilometers, their intensity and duration are not necessarily uniform across the entire region. Analysis of drought extent from 1992 to 2019 revealed that during certain years, such as 2006 and 2018, no drought events occurred, and the entire Zagros experienced wet conditions. In some years, mild droughts affected less than 10% of the region. However, between 2007 and 2017, more than 40% of the Zagros suffered from prolonged droughts, with certain years, such as 2008, experiencing drought conditions across the entire ecosystem. During this period, in 2010, over 80% of the Zagros region faced drought, and in 2017, this figure exceeded 70%. Notably, before this prolonged dry period, a relatively wet phase lasted for nearly five years.

While multiple factors have contributed to the decline of the Zagros forests, drought has been a primary driver, facilitating the impact of other stressors. The extended duration of droughts has hindered the recovery of trees, while the extreme severity of events—such as the 2008 drought, which affected the entire Zagros—has exacerbated forest decline. Although alternating wet and dry periods are characteristic of the Zagros climate, prolonged drought episodes have heightened ecosystem vulnerability. Severe droughts, when followed by a wet year, tend to have less impact compared to persistent mild droughts. Identifying areas subject to severe and continuous droughts can aid forest managers and policymakers in implementing effective conservation and restoration strategies.

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.

Subsidence as a phenomenon of land degradation and desertification is caused by human driving forces and negative water balance. Desertification is a serious and dangerous threat to natural ecosystems. Therefore, it is very important to know about the processes of land destruction and desertification that have involved a large area of the country in recent years. According to the existing subsidence map for the Namak Lake watershed, the subsidence rate in the areas with information is very intense, so that in these areas the subsidence is more than 6 cm per year. Using the IMDPA desertification evaluation model based on two criteria of underground water and land subsidence to evaluate and monitor the important indicators of desertification is the general goal of this research.

For this purpose, information layers of qualitative parameters (electrical conductivity, sodium absorption ratio) and quantitative groundwater (drop in groundwater level) and subsidence rate were prepared. The used subsidence map is related to the water year 2014-2016, which is available in Golpayegan, Arak, Qom-Kahk, Kashan, Saveh, Kamijan, Nubran, Varamin, Tehran-Karaj, Hashtgerd, Qazvin, Auj, Kabudar Ahang, Kedar, and Rezen areas. . In the next step, each index was given a weight between 1 and 4 based on its impact on desertification. The weighting is linear and the ratio is equal, so that the value 1 is the best and the value 4 is the worst. In order to investigate the effect of subsidence rate on desertification, desertification intensity was calculated in two ways. In the first case, taking into account the subsidence criterion and the underground water criterion, and in the second case, without considering the subsidence criterion, it was evaluated only based on the groundwater criterion. The final state of desertification intensity according to the IMDPA model was obtained based on the geometric mean of the criteria.

The results of combining the quantitative and qualitative parameters of groundwater based on the IMDPA model showed that 60% of the basin surface has moderate desertification intensity and almost 36% has a poor condition. The assessment of the intensity of desertification based on the criterion of underground water in the Namak Lake watershed showed that the eastern part of the basin has a higher intensity of desertification compared to the western part of the basin due to the dominance of the electrical conductivity parameter and the drop in the level of the groundwater level. Finally, the results obtained from the integration of the map obtained from the IMDPA model groundwater criteria and subsidence using the geometric mean in the Namak Lake watershed showed that the northern part of the watershed, which includes most of Qazvin, Kabudarahang, Rezen-Qahavand, Kedar, Nubran, is the intensity of desertification is higher. While in the eastern part, i.e. Tehran-Karaj range and part of Varamin range, desertification is less intense according to the two criteria of underground water and subsidence. In general, the intensity of desertification in the case of subsidence and without subsidence, the highest level is in the middle class

The study of the desertification situation based on the two criteria of underground water and subsidence indicates the intensity of desertification in the whole basin in three categories: low, medium and severe, the highest level corresponding to the moderate intensity with an area of 65.57% and then the severe category with an area of 23.83%. It is a percentage. Among the study areas, desertification in Qazvin, Kobodar Ahang and Nobran has a higher intensity than other areas, which is due to the influence of the underground water standard. In general, the results of the assessment of desertification intensity in the Namak Lake watershed showed that the most important factor in creating the conditions of desertification and destruction of the land is the saltiness of the underground water and the drop in the level of the underground water. In line with the results of the present research and making more use of the existing findings, it is recommended to check all the parameters of the IMDPA model to evaluate the state of desertification, and even if possible, the parameters of the soil criterion should be checked along with the quantitative and qualitative indicators of the water criterion.

Numerous studies have individually examined the influence of neighboring countries on dust generation in southwestern Iran (Khuzestan). However, the specific countries and regions within those countries with the most significant impact on dust events in the southwest still need to be clarified. This study aimed to identify the primary sources of dust emissions affecting Khuzestan using the Aerosol Optical Depth (AOD) index for dust detection and the HYSPLIT model for tracing dust pathways.

Dust events in Khuzestan province from 2003 to 2017 were identified using MODIS imagery and a suitable dust detection algorithm. Three criteria were applied to each event: spatial extent exceeding 50% of synoptic stations, horizontal field of view less than 5 km, and detection in at least three consecutive synoptic reports. Considering typical dust ingress into Iran at lower and middle atmospheric layers, dust pathways were investigated at 500, 1000, and 1500 meters above ground level. HYSPLIT model outputs for dust event days were combined with AOD images from each year's day before the event in Khuzestan. Areas with the highest dust emissions towards Khuzestan were identified by analyzing AOD concentrations in the days preceding dust events. Regions exceeding a threshold of 30 times the AOD concentration were designated as dust sources or intensification zones. This analysis was performed for each year and the entire period, allowing for prioritization of the most significant dust source areas.

Our analysis of dust events revealed that different regions dominated dust emissions toward Khuzestan across the study period. In 2003, northern and eastern Arabia contributed the most dust. Subsequent years exhibited varying source regions, including the Iraq-Syria border (2004), Saudi Arabia (2005), southern Iraq (2006), southern and southeastern Iraq (2007-2008), southwestern Iraq and northern Iraq alongside northern and eastern Arabia (2009), southern and southwestern Iraq (2010), western, southern, and northern/eastern Iraq alongside Arabia (2011), and again southern and southwestern Iraq (2012-2013). In 2014 and 2015, northern and eastern Arabia re-emerged as the primary source. Finally, the Iraq-Syria border, western Iraq, and southern Iraq were identified as dominant sources in 2016 and 2017, respectively. Across the entire study period (2003-2017), eastern Iraq, the Iraq-Syria border, southern Iraq, and northern and eastern Arabia emerged as the most significant dust source regions impacting Khuzestan.

Our analysis revealed that Iraq contributes the highest proportion of dust emissions impacting Khuzestan province (68.8%), followed by Saudi Arabia, Syria, and Kuwait. Considering anticipated climate change and intensified dam construction activities in upstream countries, particularly Iraq, dust generation will likely worsen. The dust originating from these regions, situated along the path of synoptic systems towards Iran, has significantly impacted the environment, especially the Zagros forests. Identifying the primary dust source areas empowers policymakers to develop tailored and effective diplomatic strategies for controlling and mitigating the effects of regional fine dust.

Climate change is one of the greatest challenges of our time to achieve sustainable development. The dangers of global warming and climate change can be recognised and planned for, so efforts should be made to identify the consequences and methods of adaptation to reduce their impact, as trees and plants are sensitive to climate change, heat and moisture stress, and forest ecosystems are affected by these changes. Climate change is one of the greatest challenges of our time to achieve sustainable development. The threats of global warming and climate change can be identified and planned for, so efforts should be made to identify the consequences and methods of adaptation and reduce their impacts because the sensitivity of trees and plants to climate change, heat and moisture stress, forest ecosystems are affected by these changes. Forest degradation due to climate change is a global phenomenon affecting many tree species. One of the major challenges to Iran's natural resources is the degradation of oak forests. The increase in temperature in recent years has lengthened the growing season of Iranian oak, and due to the lack of rainfall, the intensity of water stress on this forest species has increased. Understanding the extent of climate change in the Zagros ecosystem based on standard indicators that show climate change can help managers and planners take action to adapt to conservation and restoration conditions.

In this study, based on the standard indicators established and updated by the World Meteorological Organization, the occurrence of climate change in six sites monitoring the decline of oak trees in Ilam Province, including Sarabeleh, Mala Siah and Dalab Strait, was detected in both north and south directions. The trend slope line, trend slope error and trend significance of the indices in the statistical range P value=0.05 were calculated using ClimPACT software in R program environment. The characteristics of heat, cold, combined, and precipitation indices such as day, number of occurrences, and continuity of the index in the nearest synoptic station to each site were identified, and daily data of minimum temperature, maximum temperature, and precipitation parameters were used between 1987 and 2019. The variations of each index were plotted and analyzed as graphs in the R software environment. Accordingly, the trend slope and significant indices affecting heat stress (hot temperature indices and cold-temperature indices) and water stress were calculated with the software ClimPACT in the R programme environment.

The results of the trend and significance of thermal indicators for climate change detection showed that of the 16 heat indices studied, in Ivan station, 11 indicators showed a significant trend of about 70% and in Ilam 9 indicators showed a significant trend of about 56%.The heat-based temperature indices, especially those based on maximum temperatures, showed a significant change towards warming, while those based on minimum temperatures showed no significant trend. The study of heat waves showed that the northern and northwestern regions of the province were subjected to several periods of heat waves, which occurred with greater frequency and continuity in the northwestern part of the province (Malah Siah and Dolab Strait sites) than in the northern part (Sarab sites) of the province, confirming the emergence of high mountain regions as a result of climate change. Cold-based temperature indices of 8 studied indices in Ivan-e-Sorchrove station, 7 indices were above 87% and Ilam 3 was about 38% the trend was significantThe cold-based temperature indices in Ivan West station show a significant change in the direction of a decrease of frost and cold and their persistence and warming, and in Ilam station the decrease of cold and warming of air after 2008 indicates a decrease of cold and warming. The results of the trend and significance of the combined indices for climate change detection in Ivan West station were 100% and in Ilam station 50% showed significant trend. The combined indices confirm climate change in terms of increase in air temperature due to increase in growing season and increase in trend of change in maximum temperature. The study of the trend and significance of ten precipitation indices related to the frequency and intensity of heavy rainfall and the length of dry and wet periods showed only one index in Ivan-e-West station, which was about 10%. The station Ilam did not show significant changes in the precipitation index.

It can be concluded that zagros vegetative region in Ilam province has experienced severe thermal changes during 1987-2019 and climate change in the north of Zagros vegetative region is a type of temperature increase that has been extended to the northwestern regions of this region since 2008. The results show that in deterioration sites, in addition to increasing temperature, some precipitation has increased. Therefore, it can be said that the occurrence of climate change phenomenon causes increasing temperature, occurrence of floods, emergence of droughts and creating dust phenomenon, especially from neighboring countries and intensifying it in the country, all of these factors are the starting factors of the decline of Oak Trees in Ilam province. What seems to be important is to take necessary measures to prevent and mitigate the effects of climate change. These two measures can be effective and useful in reducing the effects of flood severity and risk. Therefore, managers and planners of forest ecosystems should have adaptive strategies to climate change in order to maintain and revive their executive plans so that Zagros can survive as a forest ecosystem. Although the occurrence of climate change phenomenon is one of the most important factors of drought and deterioration of Zagros forests, conservation and restoration of oak forest ecosystems can help reduce greenhouse gas emissions and climate change.

In most regions of Iran, the requisite water for population and industry is supplied by groundwater resources. Drought is an important factor, which affects groundwater quality. Groundwater is a renewable, limited, and vital resource for human life, social, and economic development. It is a valuable part of the ecosystem and is vulnerable to natural and human effects. Recognizing the quality of underground water, as one of the most important and vulnerable sources of water supply, has been a matter of course in recent decades. The effects of corrosiveness and sedimentation in water supply systems, water transmission, and distribution can increase operating costs and also create negative effects on human health. Therefore, the science of water quality will remain an important issue for engineers and scientists for years to come. Many methods and techniques have been invented and developed to investigate the chemical quality of water. Excessive harvests and recent meteorological droughts have changed the quality of underground water, but so far no study has been conducted in the entire Sefid-Rud Basin area to investigate the quality and the process of its changes. Therefore, the purpose of this study is to investigate the chemical quality of Sefid-Rud water which is used for the industry.

In this research, the chemical quality of underground water sources in the Sefid-Rud Basin has been studied and analyzed using the results of the qualitative analysis of water samples in deep wells, semi-deep wells, springs, and aqueducts, separately for three periods and according to the common statistical period of 18 years (2001-2018). The analyzed statistics and information include the results of a complete chemical analysis of water and parameters such as electrical conductivity (EC) values, total dissolved substances (TDS), pH, cations (Ca, Mg, Na, and K), anions (Cl, SO4, HCO3, and CO3), Na, and sodium absorption ratio (SAR) have been investigated. Water used by industries depending on the type of consumption in different sectors should also have certain qualities and characteristics. In this research, the Langiler index, which is an index for Corrosion and Scaling, was used to classify water quality for industrial purposes. To this end, the chemical quality of water in terms of chemical balance and occurrence of corrosion and scaling phenomena of underground water was classified into three categories: sedimentation, balanced, and corrosive. The Langelier index was used to measure water quality for the industry.

In the statistical analysis of groundwater in the Sefid-Rud Basin, while determining the maximum, minimum, and average values of qualitative parameters at the level of the study areas, the trend of qualitative changes at the level of their aquifers according to the EC map of the groundwater, has been analyzed. In the whole period of 18-year statistics (2001-2018) in the Goltapeh-Zarinabad and Tarom-Khalkhal areas, the average values of EC and TDS are higher than in other areas. there has been an increasing trend in the Goltapeh-Zarinabad area during the three study periods. Among the cations, the calcium ion had the highest amount (except for Goltapeh-Zarinabad and Tarom-Khalkhal areas), followed by the sodium ion. The highest amount of Na ion was observed in the area of Tarom-Khalkhal, the highest amount of Ca ion was observed in the Divandareh-Bijar, and the highest amount of Mg ion was observed in the Taleghan-Alamot. HCO3 and then SO4 ions were the main anions in the entire statistical period and all the study areas. It followed a relatively constant trend in all the study periods. According to the qualitative classification of industrial water, about 67% of the samples have corrosive properties and about 32% are depositors.

The values of EC and TDS in the three statistical periods in the area of Goltapeh-Zarinabad had an increasing trend. The sodium absorption ratio (SAR) in the entire statistical period was 2.9% with a maximum in the Tarom-Khalkhal range and a minimum of 0.8% in the Manjil and Sojas ranges. It shows the maximum values of cations for Ca ions with 3.6 in the Divandareh-Bijar range, Na with a value of 5.8 in the Tarom-Khalkhal range, and Mg with a value of 3.8 in the Goltapeh-Zarinabad range. Besides, the maximum amounts of anions including HCO3, SO4, and Cl were in Astane-Kuchesfehan, Divandareh-Bijar, and Tarom-Khalkhal areas, respectively. Qualitative assessment of groundwater resources in the Sefid-Rud Basin area for industrial use based on the Langiller index shows that the changing trend of this index has been relatively stable in the three periods, and out of 360 sources in the basin, 241 are corrosive sources, 115 are sedimentary sources and four sources have had a balanced situation. The analysis of qualitative zoning maps for industrial purposes showed that the Astana-Kuchsefahan and Divandre-Bijar aquifers, the central part of the Zanjan aquifer, and the western areas of the Goltape-Zarinanabad aquifer have sedimentation characteristics and other aquifers have corrosive characteristics.

Chemical quality is a significant and determining factor in a variety of water applications. Understanding the characteristics of subterranean water is regarded as a viable instrument for assessing water resource management. o determine the chemical quality of the groundwater in the Ghorove– Dehgolan aquifer, as well as to examine changes over three statistical periods (2001–2018), the basin was sampled for the following chemical parameters: electrical conductivity, total dissolved solids, sodium absorption ratio, bicarbonate, carbonate, chlorine, sulfate, calcium, magnesium, sodium, and potassium. Information from 276 exploitation sources on an annual scale pertaining to an 18-year statistical period was utilized to accomplish the objectives. The geographic information system (GIS) and the geostatistical interpolation method were utilized to determine the distribution of effective variables in the quality of industrial consumption in order to generate quality zoning maps of water consumption utilizing the Langelier index and the available data for the study area. The analysis of water quality variables revealed that the aquifer exhibited the highest values of electrical conductivity (669 µS/cm), total dissolved solids (430 mg/l), and sodium absorption ratio (0.95%) for groundwater quality during the period 2013–2018. In comparison to the other courses, they are lower. The assessment of industrial water quality revealed that scaling affected 22% of the water samples, while corrosion affected 78%. The examination of qualitative zoning maps intended for industrial applications revealed that the aquifers in the southern portion of the Ghorove– Dehgolan plain, along with a restricted region in the aquifer's northern section, exhibit sedimentation characteristics. Conversely, the majority of the aquifers in the area demonstrate corrosive attributes. Thus, it is imperative to exercise utmost caution when utilizing these resources in pressurized irrigation systems and industrial, urban, and agricultural water supply systems in order to mitigate potential harm to pipelines and metal connections.

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.

Over the past decade, the Zagros region, specifically its Zagros oak trees, has experienced significant impacts from droughts and climate change. Climate change has resulted in heightened desertification and oak forest decline. This study examines and analyzes meteorological droughts and their correlation with climate change. This is a prominent contributing factor to oak tree decline in Ilam Province. The focus is on study sites in the northern and southern Serabaleh regions, where oak decline has been observed.

For this study, comprehensive data on daily precipitation and minimum and maximum temperature were obtained from the synoptic station in Ilam, covering the period from its establishment until 2019. The Standardized Precipitation Evapotranspiration Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) were developed to assess meteorological drought and identify wetter and drier years. The SPI measures the deviation of precipitation from the mean value and normalizes it by the standard deviation. In contrast, the SPEI considers the discrepancy between precipitation and evapotranspiration. These indices were calculated on various time scales, including 3, 6, 12-month, and annual periods, and drought status was analyzed based on their respective classifications. To examine the role of climate change and identify influential precipitation and temperature patterns in drought occurrence, a set of four precipitation indices and eight temperature indices were calculated using ClimPACT software. These indices, developed by climate change experts, capture changes in mean or extreme weather conditions. The analysis also included wind speed. The relationship between drought indices and climate change was assessed through regression analysis and the Pearson correlation coefficient. Moreover, the study employed the Mann-Kendall and Pettitt Test to identify change points or significant abrupt changes in the time series. These tests were conducted at 5% significance and 95% confidence levels.

The study findings indicate a decreasing trend in the highest consecutive 5-day rainfall since 1995. In addition, there are insignificant reductions in the annual sum of wet days and the highest rainfall events of one or two days since 1998. This decrease in rainfall has been accompanied by increased maximum air temperatures since 1998, with a significant intensification observed from 2007 to 2015. Additionally, there has been a slight increase in minimum temperatures since 2002 and a significant wind speed since 1996. These factors have contributed to increased evaporation since 1998 and the occurrence of droughts on different time scales, ranging from six and twelve months since 1998 to three months since 2003. Global warming has influenced droughts. Three-month droughts have resulted in milder six- and twelve-month droughts, but more severe three-month droughts in oak decline, primarily due to significant changes in maximum temperatures since 2007. The occurrence of these droughts has been associated with an increase in the percentage of days with temperatures above the average since 2007, leading to more severe droughts from 2007 to 2015, with the peak in 2008 coinciding with the highest level of oak decline during the study period and under the influence of climate change phenomena.

The SPEI drought index indicates a higher frequency and longer duration of droughts during the study periods, albeit with less severity than the SPI index. This suggests that the rising temperatures during cold months, in addition to dry months, have played a role in influencing the drought conditions. The results demonstrate that drought and climate change are the primary influential factors contributing to oak tree dryness in the forests of Ilam Province. Considering the decreasing precipitation trend and increasing temperature trend observed in the studied region, the occurrence of climate and environmental hazards, such as heatwaves, droughts, and floods, may further increase.

The planet is currently witnessing the effects of global warming, including Arctic sea ice, rising sea levels, more severe forest fires, and animal migration patterns. Understanding how the planet is changing and how fast it is changing is crucial to preparing humans and adapting to a warmer world. In this study, the trend of temperature anomaly changes and the year of temperature record in Iran have been investigated and compared with the temperature anomalies of the Earth, land hemisphere (north), water hemisphere (south), North Pole, and the South Pole. For this purpose, reanalysis data related to 2 m surface temperature anomalies obtained from the European Medium Term Prediction Center (ECMWF) and processed by the Climate Change Center of the University of Maine were used. The results showed that most temperature anomalies occurred at the North Pole. After the North Pole, the temperature anomaly in Iran is more than the anomaly of the hemisphere and more than twice the anomaly of the Earth. Although the highest temperature record of the year is different in different parts. The anomalous changes in Iran since 2016 have occurred with less intensity in parallel with the anomalous changes in the North Pole, and this trend will continue in the future. The highest temperature anomaly in Iran in 2010 was about 2 degrees Celsius. In 2021, unlike in other parts of the world, in Iran, the temperature anomaly record was broken and reached approximately 2.12 degrees Celsius. Iran's temperature anomaly record in 2021 is almost three times the temperature recorded in 2016 for the entire planet and more than 2 times the temperature recorded for the northern hemisphere. High-temperature anomalies are a warning to all managers and planners at all levels and a serious threat to the country's natural resources, reserves, and water consumption, emphasizing the necessary measures to adapt and reduce its destructive effects.

Karkheh River, as the third largest river in Iran, flows a large volume of water to the Khuzestan plain every year. The construction of the Karkheh Reservoir Dam, along with several advantages, widely affects the river flow in its downstream. Ignoring the effects of these structures on the elimination or reduction of river flows, especially flood capacities, leads to investment in agriculture, industry and urban development along rivers, downstream of dams and in flood high-risk areas.

In the present study, the trend of changes in the annual and flooding regime of Karkheh River over time and in the relationship with the establishment of Karkheh Dam were investigated. For this purpose, four statistical tests (Pettitt, SNHT, Buishand and von Neumann) were used to examine the homogeneity of peak and average annual flow data at the downstream of hydrometric station and to determine the points of change and mutation. In order to determine the role of climatic parameters on river discharge, Pearson correlation test was used.

According to the opening of Karkheh Dam in 2001, the results of the study showed that the flood peak discharges in the hydrometric station downstream of the dam (Pay-e-Pol station) was equal to 1978 cubic meters per second, in the period of 32 years before the Karkheh dam opening, and with a significant reduction of 78%, is equivalent to 417 cubic meters per second in the 16 years period after the dam opening. Therefore, considering the removal of flood peaks immediately after the construction of Karkheh Dam, we can definitely observe the effect of the dam on controlling the flood peaks of Karkheh River. The results showed that the highest peak discharge correlation with SPEI parameter, at 95% significance level. Also, monitoring of satellite images show that before the opening of Karkheh Dam (2001), the floodplains were covered by water in flood conditions and after this year, despite the occurrence of floods and high peak discharge reports in Karkheh River, no water intake from Karkheh River has been observed in the floodplains.

The flood regime of the River downstream of Karkheh Dam has indicated a decreasing trend due to changes in climate drought index since 1997, which has had a steady trend since 2001 due to the opening of Karkheh Dam and shows the control of floods by the dam.

Shadegan wetland is located at the end of Jarahi watershed. This wetland is one of the most important international wetlands registered in the Ramsar Convention, which is currently undergoing ecological changes and is still on the red list of the Montero Ramsar list. This wetland is extremely important due to its high biodiversity and various functions such as flood control, air conditioning and soil erosion control, habitat of various plants and animals and providing livelihood for a part of human societies. One of the most important functions of the wetland, according to the findings of the present study, is the important role of Shadegan wetland in preventing the production and control of fine dust. There are 143 wetlands in Iran, of which 25 are registered in the Ramsar Convention. Shadegan wetland is one of the wetlands of Ramsar Convention, which in the last decade, a large area of ​​it has become dry and has become a center of dust. In this research, it is important to know that in case of drying of Shadegan wetland, which areas in which seasons will be more affected by dust due to atmospheric currents.

In this study, the boundary of the wetland was determined based on the highest water advance line during a 30-year statistical period (1988-2017). According to satellite images, the border of the wetland has been determined to be about 164,000 hectares based on the rainiest year and month. Wetland area changes were used to monitor the water level of Shadegan Wetland through Landsat TM, ETM + and OLI satellite data from 1998 to 2017 in the period of June. Three stages of preprocessing, processing and post-processing were performed on the images and supervised classification by support vector machine (SVM) method was used and the images were classified into three classes of water, vegetation and without cover or soil. On the other hand, the classification accuracy for the images was calculated using two indicators, overall accuracy and kappa. To calculate the dry area of ​​the lagoon, floor changes without cover were calculated. The most important cities around Shadegan wetland, which in case of wetland drought may be most affected by wetland dust due to proximity and proximity, and have socio-economic importance and the center of the province and port status, were identified. In this study, the cities of Ahvaz, Abadan and Mahshahr were identified and studied as areas affected by wetland dust during drought. In order to study the role of drying of Shadegan wetland in the dust of the surrounding areas, seasonal and annual dust mites were prepared and drawn. Data on the direction and speed of hourly winds along with the dust were used. Then, using WR-PLOT software, in addition to the annual long-term total rainfall, the seasonal distribution of the direction and speed of events was extracted and the rainfall related to each season was plotted and analyzed, and areas affected by drought in different seasons of the year. Wetlands with greater impact were identified.

The trend of 30-year changes in the soil cover of Shadegan wetland is increasing in total, so that according to the freshwater area of the wetland, which was obtained in this study 164 thousand hectares, 22960 square kilometers has been added to the dry area of the wetland during these 30 years. The largest soil area of the wetland in 1994 was about 87.4% of the total area of the wetland. The lowest soil area of the wetland in 1998 was about 19%. Sugarcane projects have entered the wetland from the north of Shadegan Zahab Wetland since 2002, but due to widespread drought, it has not been able to increase vegetation and reduce the soil area of the wetland.During the long-term statistical period, spring is the predominant period of pollination in Ahvaz western synoptic station and secondarily in the northwest. The southeast direction is of third importance, but nevertheless, the dryness of the north and northeast parts of the wetland can affect the south and southeast of Ahvaz in this season in Abadan synoptic station. Drought on the west side of the wetland is not a threat to the city of Abadan. In Mahshahr synoptic station, the predominant direction of long-term seasonal rainfall is northwest. In case of drought, Shadegan wetland will be affected from the northwest. During the long-term statistical period, the summer season was dominated by dust and affected in three stations, such as the spring season, with the difference that in this season, dust is more abundant. During the long-term statistical period, autumn is the predominant direction for flowering and is affected in three stations such as spring and summer, but in this season, the southeast and south directions are more intense and frequent than spring and summer.During the long-term statistical period, winter is the predominant period of pollination in Ahvaz synoptic station, west and secondarily, northwest. The southeast and south directions are of third importance, but in this season, the southeast and south directions are more intense and frequent than other seasons. In this season, due to the expansion of the westerly wind to the lower offerings, unstable atmospheric systems enter Khuzestan from the south and southeast and bring dust with them from areas such as western and southern Iraq and northern Saudi Arabia, and to the southeast. Northwest and passing through the dry parts of the lagoon and the active dust center of the southeast of Ahvaz, the metropolis of Ahvaz will face problems caused by dust in this season. Due to the cold weather and the inversion phenomenon, the dust of this season, which is associated with wetland and inland resources, has a greater impact on the field of view and causes great damage to the equipment and infrastructure facilities by subsiding on the city of Ahvaz.

Drying of wetlands due to various climatic or human factors can lead to increased dust activities. When a wetland dries out, the salts that settle in it become sources of dust. Wetland fine-grained sediments with air velocity less than the erosion threshold due to small diameter and large volume enter the air streams and are dispersed in the air. Active dust centers in the southern half of Khuzestan province have the largest area in the whole country. Shadegan wetland is bounded on the north by the dust center of the south and southeast of Ahvaz with an area of ​​185043.3 hectares and on the west by the center of the south of Horalazim and north of Khorramshahr with an area of ​​258916.4 hectares and on the east by the dust center of Mahshahr - Omidieh Hindijan with an area of ​​254654.4. Shadegan wetland joins the southeastern center of Ahvaz in case of drought from the north and northeast, as if parts of it, known as Hor Mansoureh, have become part of the southeastern center of Ahvaz in the last decade due to several droughts. Is. From the west, parts of it are connected to the dust center north of Khorramshahr and join it if the drought continues. It is connected to Mahshahr-Omidieh and Hindijan centers from the east. In recent years, parts of the wetland and dust centers have overlapped. If the wetland continues and dries, for natural and managerial reasons, more parts of the wetland will dry up and become dust centers and affect important population, political and port cities of Khuzestan Data and will face irreparable social and economic losses.

Iranchr('39')s location on the arid world belt, the occurrence of climate change and global warming and the increased in human interference have resulted in dust storms phenomenon in the western and southwestern parts of the country, especially in Khuzestan province. The present study has been aimed at investigating the existing water resources of the province for the watering operation of the southeastern dust source of Ahvaz with the first priority for providing A quick solution. Since this site is located within the catchment area of the river of Koopal, to study the discharge rate and its runoff the station of koopal number 3 was selected and its average discharge and rainfall were surveyed during the years 1982 - 12014 and 1982 – 2012 respectively and the soil conservative service method of USA along with GIS and RS tehniques were used.The results showed that the average annual discharge rate of the Koopal River was, 2.49 m 3/s, so that the highest was in winter and the lowest was in summer. On the other hand, the results showed that the studied area from the southeast of Ahwaz can produce an annual runoff volume of 34.14 million cubic meters Which is 31 million cubic meters in fall and winter seasons. Therefore, regarding the annual runoff volume of koopal River and the southeast dust source of Ahwaz, especially in the winter season because of the increasing in the frequency of south-eastern wind as the main cause of dust storms phenomenon, to carry out the operations of watering and restoring vegetation cover with a proper management water usage plan in the upstream of the river.

In this study to assess and identify the characteristics of the basin drought Hendijan - Jarahi is used statistics a climatic period (30years). To determine the best indicator of drought in a correlation matrix using Pearson correlation coefficient values of PN, DI, SPI, SZI, CZI, MCZI with a confidence level of 99% and 95% review and were compared. Indices SPI, SZI, CZI together had a strong correlation more than 0.9. the SPI drought index among them have ability to better identify the start and end time of drought, and based on the drought division into 4 groups: mild, moderate, severe and extreme. based on SPI index five characteristics of the drought were extracted; many with years of drought, the longest continuity, number of events, the years and the frequency of extreme events. In order to normalize the data of the method was applied Cox box. Among the deterministic and geostatistical interpolation methods according to the spatial dependence data Ordinary kriging was used. Then, to examine the spatial correlation between measurement data and assessment methods of estimation and modeling, drawing and analysis of semi-variograms were used Based on different methods, spherical, exponential and Gaussian features vario gram on the basis of Nagget and Sill, the variance structured to non-structured Proportion, the Mean, RMS, ASE RMSS, a suitable method was chosen for zoning. The results based on the five characteristics of the study due to the large difference topography and variety of terrain and other natural and climatic diversity, characteristics of drought in the basin does not follow of a certain order. But overall abundant number of years with the drought and the highest occurrence of severe drought are more than half of its eastern extreme in the West basin that most have occurred in recent decades.

In recent years, the crisis caused by dust in the southeastern regions of the country has been one of the natural-human events affecting the daily lives of citizens and the economy of the region. Increasing access to various data processing sources has expanded dust modeling at various levels, including local, regional, and global levels, and has helped to understand the mechanism of complex natural systems. dust Modeling helps to identify the main factors that create it and the importance of each factor. One of these models that are used to detect the concentration and intensity of dust in the atmosphere and the range of this phenomenon and determine its origin is the dust model (NMMB / BSC). The purpose of this paper is to identify and monitor dust from the Gavkhoni basin by two methods of visual interpretation and tracking in satellite images using the mentioned model. Identifying areas with the possibility of dust and its synoptical study can be an important step in managing this phenomenon in the region.

In order to determine the potential areas of high concentrations of dust in the region, first in the period of 2016-2016, pervasive storms in the region were determined on a monthly basis based on the Aerosol optical depth parameter (AOD). Then, by the parameter of the minimum visibility and continuity of dust events obtained from the information of synoptic stations of the Meteorological Organization, the days with the lowest field of view and the highest continuity in the specified months (months with the highest AOD concentration) were selected. The Aerosol optical depth was calculated by using the Modis sensor and the Deep Blue algorithm. The MMB / BSC-Dust model was used to identify the most dust suscribted areas in the Gavkhoni basin. With the help of this model, dust transfer routes were monitored for three hours within 72 hours after the occurrence. Accordingly, in the next step of 25 model output maps for each time period, a map with the highest dust concentration in the basin was determined. To test the relationship of these parameters to the high concentrations of dust the output was then compared with the Synoptical maps and dust images of the Modis sensor dust storm from the Worldview database. In Synoptical studies, the goal is explaining the key relationships between the atmosphere and the environment. In order to determine the atmospheric patterns in the basin on the studied dates, the geographical range of 20 to 50 degrees north and 40 to 65 degrees east to receive digital data was determined. The hourly data of winds of different atmospheric levels of 100, 500, 700 and 850 hectopascals for days with the highest dust concentration were obtained from NCEP / NCAR center and the obtained maps were compared and analyzed with each of the dust concentration patterns.

The selected image of the 72-hour period on 4/6/2014 shows that the basin is affected by the southwestern regions of the country, especially the dust centers of Khuzestan and Iraq, which gradually affect the basin during the movement towards the central regions of the country. Images of the Modis sensor also confirmed the presence of this dust mass on the southwestern regions of the country and affected the basin on this date. The image of 4/25/2015 proved the existence of a dense dust mass in the southwestern regions of the country and the impact of the Gavkhoni basin from this mass. On this date, parts of the basin, including the eastern part of Gavkhoni Wetland and the center of the Little Spring Basin, have been producing dust. On this date, parts of the basin, including the eastern part of Gavkhoni Wetland and the center of the basin, have been a small source of dust. The dust event that occurred on 1/10/2016 shows that the basin is affected by dust sources in the Central Desert so that by moving the dense masses of dust from the central desert and the Black Desert, the basin was affected by them. And the central areas of the basin acted as a source of dust and contributed to the intensification of dust concentrations. As can be seen in the dust analysis, due to the low pressure in the center of Iran due to cyclonic rotation (counterclockwise in the northern hemisphere) on the north and south sides, the east wind and the west wind have dominated, respectively. The dominance of the western wind with orbital motion in dust storm events has been proven in most of the identified dates. In the most recent case, in 2016, we witnessed the expansion of a high-pressure center across the country and the change of this trend and the dominance of the east wind in the high levels of the atmosphere. An examination of the condition of the winds that took place on 13/3/2014 at 0-06 GMT shows the formation of centers with speeds higher than 12 m/s in the formation of dust centers. The winds blow from west to east and the dust passing through the basin originates from the western parts of the country, including the dust centers of Khuzestan and Iraq provinces. In this case, we have witnessed the dominance of unstable low-pressure centers on the surface of the basin, which can be one of the main factors in aggravating the dust phenomenon on the surface of the basin. Examination of omega winds (vertical winds on the ground) indicates the formation of an air ascent center on the range of the formation of high-speed wind nuclei and dust centers. The second incident occurred on 2/2/2015 at 3:00 PM GMT. Examination of wind direction maps shows the formation of centers with a speed of more than 25 meters per second with west-east direction on the surface of the western regions of the country and Gavkhoni basin, which aggravates dust production in sensitive areas such as Khuzestan and its movement Towards the Gavkhooni basin and affecting the basin. Examination of wind conditions to high atmospheric levels also showed that the wind regime was constant while increasing its speed at all atmospheric levels. An examination of the maps of omega winds (vertical winds on the ground) and sea surface pressure indicates the formation of an airborne and unstable (low pressure) center on the region, thus helping to aggravate the dust situation in the region. An examination of the dust storm that took place on 1/10/2016 at 6:00 PM GMT showed the formation of high wind speeds above 17 m/s in the eastern regions of the country, which are in the east-west direction at 850 ha Pascal level. he formation of these high-speed nuclei and the blowing of winds from the east to the basin have affected the Gavkhoni basin from the dust produced from the central desert and the black desert. Vertical winds also indicate the rising and falling currents and the movement of winds from high pressure (east) to low pressure (west) and the formation of east-west currents.

The results of this study showed that the source of dust occurrence in Gawkhuni basin is the Khuzestan and Iraq dust production centers, central desert and small parts of the basin center and around Gavkhuni Wetland. In addition, a synoptic examination of suitable areas of dust occurrence revealed that at the dates of the dust storms, low-pressure zones and high-velocity cores are formed at different levels of the atmosphere over the area, which is associated with the direction of the winds and the movement of dense masses of dust toward the basin.

Gavkhuni wetland has faced numerous changes in its dry and humid surface due to some climatic and human factors in recent decades. This study aims to investigate the role of drought in producing and intensifying dust phenomena in the center and surrounding areas of Gavkhuni wetland. The physical changes of the wetland are first determined using remote sensing and GIS techniques. Then, the number of days with dust is identified using data measured at selected synoptic stations. Results showed that the wetland had its highest moisture level about 89% of the surface of water in 1993, and then there was a gradual decline each year since 1993. It has been more dried so that the wetland water level was less than 10% in 2013 and has been completely dried from 2013 to 2019. The results of the Lancaster index indicate most of the sand dunes in this area have been activated during the study period. Correlation analysis for annual and seasonal dust days at stations around wetland do not show a significant relationship with wetland drying condition in most of the stations. It is statistically significant for Isfahan station in spring and summer at 1%, and in autumn at 5%. However, since the direction of the Isfahan station storms is from west to east in spring and autumn, and the Gavkhuni wetland is located in the east of Isfahan, the relationship cannot be accepted. This relationship is significant for Shahreza station in summer and Aghda station in autumn at a 5% level. The directions of dust storms are from east to west towards Shahreza in summer, and from west to east towards Aqda in autumn. Therefore, increasing the trend of dust production in these two regions and seasons, considering the positive and significant correlation coefficient could be due to the dry surfaces of wetland in recent years.

This study investigates and analyzes the decades of change in climatic zones in Karkheh, Karoun, and Zohreh - Jarahi watersheds. For this purpose, the database of temperatures and precipitation networks during the period 1976-2015, with a spatial resolution of 15 x 15 km, formatted in the conical Lambert image system, was used. In fact, because these two elements are the most important climatic drivers in the study area and the changes of other elements in these two elements are more visible, they have been used to study and analyze the climate change zone. After establishing the database, cluster analysis was used to identify climatic regions, and the audit analysis was used to validate it. Cluster analysis was performed on 52 indices of temperature and precipitation (monthly and annual average, coefficient of variation of temperature, and precipitation monthly and annual changes) during different periods, and climatic zones and their changes were analyzed. Based on the results, three climatic zones including humid and moderate zone, hot and dry zone, and very hot and dry zone were identified in the study area. The results showed that in recent periods, the humid area, in addition to having spatial displacement, its area reduced so that in the fifth period, the area reached less than five percent. Also, the hot and dry zone, stretched as a strip from the northwest to the southwest of the study area, had less spatial displacement, unlike the humid area, while its area increased in recent periods. On the other hand, the area of the very hot and dry zone has increased towards recent periods. Spatial and temporal increase of hot and dry climates and very hot and dry climates and decrease of the humid zone has been able to lead to the development and intensification of dust source, especially downstream of the studied watersheds.

The purpose of this study was to investigate the characteristics of wind regime and sand transport potential in the Sarakhs Erg, located in the north-eastern corner of Iran. Accordingly, using the data of wind speed and direction (1978-2016) of the Sarakhs synoptic station, the potential of sand transport (DP), Resultant Drift Potential (RDP), Resultant Direction Drift (RDD), and the ratio of RDP/DP were calculated using Fryberger-Dean (1979) method. Also, the characteristics of erosive winds and temporal changes were investigated based on sand transport (DP) potential. The results showed that the dominant wind direction and the sandy wind were northwest. Agricultural lands, especially in the fall season, as well as the sediments of the Tajan Border River, were the sources of wind sediments. In general, wind energy in the Sarakhs region based on the sand transport (DP) potential is put in the low class (DP=193 v.u) with the highest and the lowest in July and November, respectively. On the other hand, sand discharge capacity based on the average sand carrying potential (DP = 193 v.u) for this range was estimated to be about 13.51 m3 in width. Field studies and satellite images showed that sand and nebka zones were two main forms of wind sediments in Sarakhs Erg sediments.

Precipitation is the most important climatic factor affecting water supply and is one of the most variable meteorological phenomena. In order to study the precipitation trend in basins leading to the internal dust source of Khuzestan province, the gridded data of the National Iranian Drought warning and monitoring center with a grid resolution of 44km were used. This gridded data were made through reanalyzing daily, monthly, and yearly rainfall data from the synoptic, climatological, and meteorological stations of Meteorological Organization and the precipitation and evaporation stations of the regional water company, respectively using ArcGIS software. In order to study the decade by decade precipitation trend, 50 years precipitation data were used in form of five decades from 1968 to 2017, then spatial variations of precipitation in three basins of Karun, Karkheh, and Zohre-Jarahi were detected by the zoning of the precipitation data and their maps were prepared. To detect the changes in time series of precipitation data, the homogeneity tests of Pettitt's were used, which is available in Excel using the XLSTAT statistical software. The result showed that there were two main precipitation cores in the Karun Basin in the fifth decade. The main precipitation cores of previous decades in the Karkheh and Jarahi-Zohre basins were weakened. The highest decrease in precipitation occurred in the downstream of the basins at the location of dust sources. Decade changes in precipitation showed that the decrease in rainfall started two decades ago in the three basins of Karun, Karkheh, and Zohre-Jarahi. This decline was clearly evident in the fifth decade and its harmful effects due to the increase in other parameters such as temperature and evaporation were doubled and contributed to the activation centers of dust.

Wetlands ecosystems play an important role in the ecosystem in arid and semiarid regions. Drying these ecosystems can be caused by human and natural factors; Meteorological droughts are caused by natural factors such as precipitation and temperature rise and evaporation, but in the event of hydrological drought, despite the above factors, human factors in water management play a key role. Climate change and ongoing droughts with rising temperatures and evaporation and declining humidity and runoff in catchments and by human intervention through the construction of dams and large irrigation networks, the entry of agricultural wastewater, industrial and urban pollution And the oil ecosystem has made it difficult for wetlands.
The trend of climate change and the occurrence of continuous droughts with increasing temperature and evaporation and decreasing humidity and runoff in catchments, especially in the catchment area of wetlands located in arid and semi-arid regions; Like Shadegan, and due to human intervention, ecosystems have caused wetlands problems and caused them irreparable damage. The purpose of this article is to monitor the wetland surface area of the wetland over a period of 30 years. The relationship between the occurrence of hydrological drought and the water area of the wetland and the calculation of the drainage water entering the wetland and its relationship with the water area of the wetland is one of the objectives of this article. The results of this paper will help water resource management decision makers to provide both wetland water supply from the Jarahi River freshwater source and integrated sugarcane drainage potential with respect to its treatment as an opportunity to save the wetland as an ecosystem. Live help with multiple functions.

. In order to investigate the relationship between hydrological drought and its role on Shadegan wetland changes, Streamflow Drought Index (SDI) was used. For Jarahi basin with 10 stations that have a 30-year period. Hydrological drought characteristics including the frequency of continuity and magnitude were calculated and analyzed for decades for the catchment area of the wetland. Landsat TM and ETM + and OLI satellite images were used in the years 1988 to 2017 in June. Three stages of preprocessing, processing, and post-processing on images are carried out and to categorization use of Supervised vector machine (SVM). The images were classified into three classes of water, vegetation, and no cover or soil In order to evaluate the classification accuracy of classified images, two indicators, total accuracy and kappa were calculated. Changes in Discharge The Shadegan hydrometric station was calculated as the last entry point of the Surgical River to the wetland and other water sources entering to Shadegan wetland, whose discharge was measurable and available, such as sugar cane Drainage water And their values were compared with changes in wetland area water.

Naturally, the most important source of water for wetlands is seasonal and permanent rivers and runoff from the watersheds leading to them. The frequency of occurrence, persistence and magnitude of drought in the watershed area of the wetland leads to a decrease in freshwater inflow to the wetland. Meteorological drought, especially in the last decade, and the development of irrigation networks and the construction of dams have been the main reasons for the occurrence of hydrological drought in the watershed, resulting changes in the water level of Shadegan wetland. The frequency of hydrological droughts of the decade in the watershed of Shadegan wetland has been increasing and in the last decade the drought storm has reached 8 to 9 event. The persistence of hydrological droughts in the basin has an increasing trend, although there is no continuity in the first decade, but in the second decade in most stations the continuity is three years and in the third period the drought is 8 years. At Shadegan station, which is the last water entry station to the lagoon, the continuity has reached 9 years. The study of the large size of the hydrological drought of the decade in the watershed of Shadegan in the first and second decades was low, but in the third decade the magnitude of the drought reached more than 8, which indicates the persistence and pervasiveness of the drought in the third decade.
The trend of 30-year changes in the water area of Shadegan Wetland is increasing. Prior to the arrival of the drainage system due to sugarcane projects, the highest water area of the wetland was 22.4%, which was due to the conditions of the watershed related to the wetland, which faced severe wet conditions. In 2005, the wetland's water area reached its maximum value during the 30-year period under surveillance; in the previous year, 240 million m3 of Drainage Water entered the wetland from sugarcane projects, and this year 266 million m3 of Drainage Water entered the wetland. In addition, mild wetland conditions have prevailed in the watershed this year. Therefore, the water area of the wetland in the early years was subject to precipitation conditions in the wetland watershed and since the year that sugarcane drainage entered the water of the wetland, it has been subject to precipitation conditions and the volume of incoming drainage water from sugarcane projects.

The results showed that although the frequency of drought persistence and magnitude increased in recent decades compared with other decades, the area of wetland water has increased trend. The area of the wetland in the last decade has not been consistent with the discharge exit from the last hydro meteorological station of Shadegan, but has been associated with the total amount of water entering the sugar cane and discharge Shadegan hydro meteorological station. Therefore, sugarcane Drainage water, regardless of its quality, has played a key role in the recovery of the Shadegan wetland as a living ecosystem in recent decades, due to the severity and severity of drought.

Water quality, as its quantity, is one of the most important determinant factors for its application in various uses. Physical and chemical properties of water play an important role in categorizing and evaluating water quality. With the aim of detecting the water chemical quality of Gupal river in the south of the country and studying its annual changes during the years 1982 to 2011, its physical and chemical parameters were studied. Since the presentation of the results of water quality analysis in the graphical form simplifies and makes faster understanding of complexity of surface water systems, graphical methods such as Wilcox, Schuler, Piper and Collins diagrams were also used. The results of variation and trends analysis of water quality parameters showed that in spite of the decreasing in the trend of acidity and flow rates, other chemical parameters of water had an increase in their trend and their terms was in order of 5, 10, 20 and 30, respectively. Increasing in the trend of variation in the water quality parameters and dissolved salts indicates a decrease in water quality and an increase in dissolved salts. The Wilcox diagram showed that the water lied in the class of C4S3and was inappropriate for irrigation and agricultural uses, and Schuler’s diagram showed the water quality is not acceptable and in terms of industrial water consumption the river was precipitate and the Piper diagram showed that the dominant ions in this river are sodium and sulfate, and water has type and facies of sulfate sodic.

Despite the large extent of the areas affected by 120-day Sistan winds, Zabul region with specific topographic location has the highest and the most severe storms in the east of the country. In order to identify and analyze the dust pattern of the Zabul region and to distinguish it from other parts which are affected by the famous 120-day winds of Sistan, environmental databases; dust codes, and NCEP / NCAR database with a spatial resolution of 2.5× 2.5 degree and latitude longitude of sea level pressure data corresponding to the peak days of dust during the period from 1987-2016 were used. In order to extract atmospheric patterns of dust events on sea level pressure data, cluster analysis was performed in MATLAB software. Finally, four patterns were extracted and for each pattern one day which has the most correlated with other days was selected as the representative day of that pattern. Out of four patterns the dominant pattern with the most frequent occurrence was selected, and July 13-16, 2016 was considered as the representative day for this dominant pattern. For this purpose, the synoptic maps of ground pressure, temperature, equatorial and jet flow in the lower layer of the atmosphere, wind field, and direction of the flow at ground level and the synoptic half instability of the air were plotted.
Results indicated that the Zabul area has the greatest potential for the production of dust due to the gradient of high pressure changes and also the presence of small-grained sediments of the rivers as well as wetlands and the locating in western margin of the low-pressure zone which has the thermal nature and the interaction of the low pressure with the high pressure which is called Turkmenistan high-pressure, Hindu Kush, northeast of Iran and north of Caspian sea. This low pressure in the lower layer of the atmosphere through the dust suction and counter-clockwise movement by passing on the sources of dust in the Zabul area prevented from the penetration to lower latitudes by the impact of the 120-day winds of Sistan and caused to further transportation of sand and dust particles to Afghanistan. Therefore, in regard to situation of Zabul in ratio to this low pressure, which is peaked in July, and distinguishes it from other areas affected by 120-day winds, special arrangements should be taken into account to reduce the intensity of dust storms.

Jazmurian basin in the southeast of Iran is one of the most important and vital basins. Due to the lack of surface water resources and placing in the priority of use this basin is faced with a sharp decline in the level of underground aquifers.TheThe aim of this study was to identify the factors affecting groundwater resources and predict the groundwater level and its variation in Jazmourian Basin. In this study by considering the importance of identifying the factors affecting the condition of groundwater resources and the causes of decline, initially, the geological and geomorphological features of the basin and its impacts on the quantity and distribution of the groundwater resources were studied. Then, the effect of hydrological droughts with using two streamflow index (SDI) and the standardized precipitation index (SPI) at hydrometric, pluviometric, and synoptic stations located in the basin aquifers was studied. The portion of perceptions on changes in groundwater resources by wells, spring, and aqueducts, as well as the impact of surface structures and expenditures on land surface level changes were determined. In addition, the average monthly and annual mean of groundwater levels during the years 1370-93 were investigated using time series models to predict groundwater changes by the year 1420. The study results on the effect of different factors on groundwater water changes showed that hydroclimatic droughts, although affecting underground water changes, did not have a significant effect. The dams and deep and semi-deep wells with negative correlations of 0.83, 0.75 and 0.68 had the most negative effects on groundwater drops, respectively, and the average discharge of wells and springs increased significantly with increasing groundwater level. Also, the study of changes in groundwater level in the basin indicates a significant decrease (0.37 m / year) and predictions show that in the coming years it will face more severe losses. The high level of decline was observed in the summer with a change of 1.96% and in the autumn it was 1.78% lower than the other seasons. Overall, the results showed that if the current trend of exploitation of the groundwater resources continues, the region will be facing more challenges.

Precipitation temporal trend analysis and study of the drought condition have been of great concern during the past century because of the attention given to global climate change by the scientific community. The aim of present study was to investigate and analyze the rainfall trends and its affected drought conditions in Jazmurian basin using non-parametric mann-kendall method and multidimensional comparison of drought indices including Standardized Precipitation (SPI), deciles (DI), the percentage of normal (PNI), Chinese Z (CZI) and the Z score (ZSI) with rainfall data from 24 gauged stations for the period of 1983 to 2013. For this, the drought indices were calculated, and then categorization was performed on the basis of similarity and correlation using cluster analysis method. The results proved a positive and significant increase in the rainfall amount of 1992-1993 and 1995-1996 years. Statistical analysis showed that the highest amount of rainfall occurred in the years of 1992-93, 1995-96 and 2004-2005 and the lowest in the years of 1983, 2000, 2003 and 2005 in the basin. Cluster analysis showed that the ZSI and PN indices with similarity of hundred percent in the diagnosis of wet and dry periods, intensity, duration and continuity were completely similar and had the highest similarity among all the groups. The CZI and SPI with 99.5 percent similarity were in the second level of similarity as well. Validation of the results through the numerical comparison of SPI and CZI indicates the same trend of two indicators and little differences in presenting the drought conditions of Jazmorian basin. However, in assessing the severity of droughts, CZI showed more severe drought condition. Overall, the results showed a greater focus of the drought in the southern east and southern parts of the basin indicating the high probability of drought occurrence potential of the basin. Therefore, the study of drought through CZI and SPI indices in the basin of Jazmorian is suggested for the proper policy making and management of water resources regarding conservation and increasing of the productivity from environmental, economic and social point of views.