Yaser GHasemi Arian; Hadi Eskandari Dam aneh; Maryam Naeimi; Adel Jalili; Samira Zandifar; Azadeh Gohardoust; Sakineh Lotfinasabasl
Volume 32, Issue 1 , May 2025, , Pages 1-17
Abstract
Background and objectivesLand 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 ...
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Background and objectivesLand 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.MethodologyThe 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.ResultsAnalysis 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.ConclusionAs 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.
Fatemrh Dargahian; Azadeh Gohardoust; Sakineh Lotfinasabasl; Sara Teimouri
Volume 31, Issue 1 , June 2024, , Pages 74-92
Abstract
Background and ObjectivesNumerous 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 ...
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Background and ObjectivesNumerous 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.MethodologyDust 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.ResultsOur 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.ConclusionOur 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.
Mohammad Khosroshahi; Zahra Saeedifar; Khosro Shahbazi; Samira Zandifar; Sakineh Lotfinasabasl; Azadeh Gohardoust; Fatemeh Dargahian; Maryam Naeemi; Tahereh Ensafi Moghadam; Leila Kashi Zenouzi; Zohreh Ebrahimi Khosefi; Morteza Khodagholi
Volume 30, Issue 4 , February 2024, , Pages 521-541
Abstract
Background and objectivesWind 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 ...
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Background and objectivesWind 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. MethodologyIn 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. ResultsThe 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. ConclusionIn 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.
Seyed Jafar Seyed Akhlaghi; Azadeh Gohardoost
Volume 30, Issue 2 , September 2023, , Pages 230-246
Abstract
Background and objectivesDesertification is a multidimensional process initiated by the interlinking of environmental and human constructs. It is expanded by combining and synergizing natural conditions, climate change, and human pressure factors. This study aimed to combine economic, social, and managerial ...
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Background and objectivesDesertification is a multidimensional process initiated by the interlinking of environmental and human constructs. It is expanded by combining and synergizing natural conditions, climate change, and human pressure factors. This study aimed to combine economic, social, and managerial factors affecting desertification in the Niatac dust corridor in Sistan and using the application framework of multi-criteria decision-making models, the most important indicators of desertification Human-making is prioritized and introduced in the study area to be used in management and control of desertification and dust phenomenon in the region. MethodologyThis research is survey research. At first, based on the sources and conventional models of desertification assessment, 20 appropriate indicators were selected in the form of 5 criteria using a combination of different models such as IMDPA, MICD, and MEDALUS, along with the opinions of experts and experts familiar with the region, as well as the research executive team. Data and values related to the indicators were collected through various information sources, including reports from the Statistical Center of Iran, the Ministry of Energy, the Agricultural Jihad Organization, and the General Directorate of Natural Resources of the province, as well as structured interviews in the region, and then the factors and indicators under study were ranked using TOPSIS multi-criteria decision-making method, and finally, a zoning map of the study area was prepared by each of the anthropogenic factors. And it was presented. ResultsAccording to the results, policy and rules (32.5%), economics (25.1%), water, and agriculture (20.6%) had the greatest impact on desertification. The ranking of indicators showed that the Hamoon wetland rights index and Niatak River with a coefficient of 0.69, the institutional and organizational coordination index with a coefficient of 0.6743, the rural development index with a coefficient of 0.6743, the efficiency index of conservation and recovery of desert areas with a coefficient of 0.5596, poverty index and household income with a coefficient of 0.5988, grazing pressure index in rangelands with a coefficient of 0.4821 and agricultural land release index with a coefficient of 0.5596 had the greatest impact on The land was destroyed and deserted. ConclusionThe results obtained in this study indicate the importance of anthropogenic factors in the desertification of Sistan. By relying on the results of this study that 62% of the land in the Niatak wind erosion corridor is subject to severe desertification, a long-term action plan implementing suitable measures for rehabilitating desert lands of the region by the custodians should be prepared. On the other hand, TOPSIS, used in this study to determine desertification intensity, is a relatively accurate method when using the appropriate indices. It also has simplicity, flexibility, and low cost. This method can help managers and planners of the desert area identify priorities affecting desertification. It can also provide appropriate programs for managing and restoring desert areas.
Sakineh Lotfinasabasl; Fatemeh Dargahian; Azadeh Gohardoost; Asad Hatam Baharvand; Samaneh Razavizadeh
Volume 30, Issue 2 , September 2023, , Pages 335-354
Abstract
Background and ObjectiveOver 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 ...
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Background and ObjectiveOver 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. MethodologyFor 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. ResultsThe 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. ConclusionThe 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.
Hamidreza Abassi; mohammad kashki; Mohammad Reza Rahdari; azade gohardoust; Sakineh Lotfi Nasab Asl
Volume 27, Issue 2 , June 2020, , Pages 371-384
Abstract
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 ...
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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.
azade gohardoust; Amir sadoddin; majid Ownegh; Ali najafinejad
Volume 24, Issue 3 , October 2017, , Pages 524-536