Physical Geography Department, Faculty of Geographical Sciences, Kharazmi University, Tehran, Iran. , ahmadabadi@khu.ac.ir
Abstract: (162 Views)
1- Introduction
Wind erosion is one of the important natural processes of soil degradation, particularly in arid and semi-arid regions, which has extensive environmental and economic consequences. This phenomenon, through the transport of soil particles and the production of dust, has destructive effects on ecosystems and local economies. Decreased agricultural productivity, destruction of infrastructure, and reduced quality of water resources are among these impacts. Studies show that wind erosion occurs in three stages: particle detachment or removal, particle transport (suspension and surface creep), and deposition. In the last two decades, advancements in remote sensing technology and the increased processing power of computers have enabled the study of wind erosion with greater speed, accuracy, and on a larger scale. The Sentinel 2 satellite, with its 10-meter spatial resolution and 5-day revisit cycle, has become one of the most accessible and practical sources of remote sensing data for mapping and modeling soil erosion. Since no comprehensive studies have been conducted regarding the relationship between wind erosion and dust production in the Aradan and Garmsar counties, this issue highlights the necessity for a precise and targeted study. In addition, recent studies have shown that aerosol optical depth (AOD), derived from satellite sensors, can be used as an effective proxy for estimating dust concentration and atmospheric turbidity, particularly in regions lacking ground-based observation stations. This research aims to investigate and analyze the correlation between wind erosion and dust in the Aradan and Garmsar counties and to employ modeling and satellite data to improve natural resource management and reduce the consequences of this phenomenon.
2. Methodology
This study employed a combination of remote sensing, climatic, and field data to analyze wind erosion and dust phenomena in Aradan and Garmsar counties. Horizontal visibility, average rainfall, wind speed, and prevailing wind direction data (2009–2018) were collected from four meteorological stations: Garmsar, Semnan, Kashan, and Tehran-Mehrabad. Sentinel-2A imagery (2022) was preprocessed and analyzed in SNAP to assess vegetation changes and identify wind erosion-prone zones. MODIS images from Terra and Aqua satellites were used to detect and track dust sources and movement, applying Brightness Temperature Difference (BTD) and Aerosol Optical Depth (AOD) analysis in ENVI 5.1. Field surveys were conducted to validate remote sensing outputs, with GPS data and photographs collected from active dust sources and degraded areas.
3- Results
The majority of the Aradan and Garmsar counties exhibited very low, low, and moderate levels of dust dispersion, showing a clear north-south trend. The average dust concentration across these counties also follows this north-south gradient. Since dust concentration is inversely related to horizontal visibility, areas along the Mashhad-Qom and Mashhad-Tehran roads, as well as urban and rural centers located in zones with very low and low visibility, experience very high dust levels. In contrast, the southern regions closer to Kavir National Park and the Salt Lake show higher visibility and correspondingly lower dust concentrations compared to the northern part of the study area.
The wind erosion zones were classified into a detachment zone covering 1060 km² (about 11%), a transport zone in the east of Aradan county and Kavir National Park covering 20 km² (0.02%), and a deposition zone of 112.3 km² (about 1%). Field visits confirmed the presence of active clay and sandy plains in the detachment zone and sand dunes, nebkhas, and sand tongues in the deposition zone. The resulting erosion zone maps highlight that the southern and eastern parts of the counties, especially near Kavir National Park, exhibit the most intensive erosion activities.
The spatial distribution of wind erosion zones on the dust dispersion map shows two distinct categories: the first is near urban and rural areas and infrastructure such as the Mashhad-Qom and Mashhad-Tehran roads; the second is in the southern and southeastern parts of the study area where all three wind erosion stages (detachment, transport, and deposition) occur.
4- Discussion & Conclusions
The analysis of satellite imagery combined with ground-based horizontal visibility data revealed that changes in vegetation cover, soil moisture, and human activities are the primary drivers intensifying wind erosion and decreasing horizontal visibility. This study demonstrated the valuable role of Aerosol Optical Depth (AOD) derived from satellite remote sensing as a complementary parameter to ground measurements. The integration of AOD data helped to overcome the limitations posed by the sparse distribution of ground monitoring stations, enabling the estimation of dust concentrations in regions lacking in situ observations. Such combination enhances the spatial and temporal coverage of dust assessment, providing a more comprehensive understanding of dust dynamics. The findings emphasize the importance of employing advanced remote sensing technologies and data fusion techniques for improved natural resource management. Practical measures, including soil stabilization, increasing vegetation cover, and minimizing destructive human activities, are critical to mitigating the adverse effects of wind erosion and dust pollution. The southern and central parts of the study area were identified as the most vulnerable zones due to their environmental conditions and anthropogenic pressures. This integrated approach can significantly contribute to regional planning and environmental policymaking by enabling better monitoring and management of dust-related hazards. Implementing sustainable management practices in these sensitive zones will help reduce the environmental degradation and adverse health effects associated with wind erosion and dust storms.
Received: 2025/06/10