Identifying the centers of dust and analyzing the factors influencing its occurrence Based on Remote Sensing Data (Case Study: Southwest Iran)

Dust, or fine dust, refers to very small and light particles of silt, clay, or sand that are transported by the wind over long distances due to wind erosion and the spread of desertification. Dust storms have emerged as a significant threat to public health in recent years. This phenomenon is influenced by natural factors, such as climatic conditions, climate change, hydrogeomorphological features, and vegetation, as well as human factors, including land use changes, erosion, and other anthropogenic activities. Dust is one of the most harmful natural disasters in arid and semi-arid regions of the world, particularly in Iran, and has caused substantial environmental and human problems in these areas.This phenomenon has significantly affected various aspects of life in the region in recent years. Among the areas exposed to dust-related hazards are the southwestern regions of Iran. Due to climatic conditions, wind speed and direction, and the presence of sand dunes, these areas are prone to becoming dust centers. This has resulted in frequent occurrences of dust storms over a large portion of the year in the southwestern regions of the country. Given the importance of the issue, this research investigates the concentration of dust in the southwestern region of Iran and analyzes the factors influencing its occurrence.

In this research, Google Earth images, MODIS satellite images, CHIRPS satellite images, and a 30-meter SRTM digital elevation model were utilized. The most important tools used in the research were Google Earth Engine (for preparing dust concentration maps and average precipitation and temperature maps of the region), Google Earth (for creating geomorphological unit maps), ArcGIS (for generating desired maps), and IDRISI (for implementing the WLC model).Additionally, various indices and models were applied, the most notable being the AOD index (for generating dust concentration maps) and the WLC model (for identifying areas prone to dust center formation). This research was conductedin several stages.In the first stage, the Google Earth Engine system, AOD index, and MODIS satellite images were used to prepare the dust concentration map for the study area from 2018 to 2022. In the second stage, the correlation between dust concentration and environmental factors, such as vegetation parameters, wind speed, precipitation, temperature, geomorphological units, and altitude, was analyzed. In the third stage, areas prone to dust center formation were identified using the WLC model.

Google Earth Engine and the AOD index were employed to assess the dust concentration in the southwest of the country. The analysis involved utilizing MODIS satellite images to generate dust concentration maps for the years 2018 to 2022. Based on these maps, the highest dust concentration was observed in the central regions of Khuzestan Province and the southern regions of Ilam Province. Conversely, the lowest dust concentration was recorded in areas adjacent to Horulazim Wetland, the Arvand River, and the southern coastline.The relationship between the dust concentration index and environmental factors indicated that the highest dust concentrations were associated with areas characterized by low NDVI coefficients, low rainfall, high temperatures, low altitudes, and sand dunes.

The findings of this research showed that the correlation coefficients between dust concentration and the parameters of NDVI, wind speed, precipitation, temperature, and altitude were 0.63, 0.156, 0.557, 0.489, and 0.602, respectively. Additionally, the dust concentration coefficients in sand hills, plains, hills, and mountains were 0.71, 0.64, 0.47, and 0.23, respectively.After analyzing the factors affecting dust concentration, a map of areas prone to dust center formation was generated based on the identified parameters. The results revealed that a significant portion of the study area, including the northwestern parts of Ahvaz City and the northern parts of Hovizeh City, showed a high potential for forming dust centers. Similarly, the areas between the cities of Omidieh and Ahvaz also demonstrated substantial potential for dust center formation.The overall findings indicate that under the influence of environmental factors, a large portion of the southwestern regions of Iran is prone to dust center formation. Among the environmental factors, vegetation density played the most significant role in dust control. Therefore, the most effective solution to reduce and manage dust in the region is to establish vegetation in barren areas, particularly in the sand fields of the region.