Using Remote Sensing Technology and Geographic Information Systems to Study the Reality of the Sand Dunes of Featured Area in the Syrian Badia
2023
Ali Al-saad
Sand movement and the formation of sand dunes are significant natural phenomena that occur in desert and arid regions worldwide. Sand movement is driven by active winds, which transport sand particles from one place to another. The speed and direction of sand movement vary based on wind strength. In this study, we focused on a prominent area in the Syrian desert, spanning between the Deir ez-Zor and Homs governorates, covering an area of approximately 23,748.5 km². This region is crucial due to its susceptibility to sand encroachment. The objectives of this research were as follows: 1. Developing a Reference Equation: We aimed to create a reference equation applicable to a time series of satellite images. This equation would help calculate sand ratios and spatial distribution within the study area. 2. Mapping Sand Distribution: We generated maps illustrating the spatial distribution of sand across the study area during different time periods (between 2004 and 2022). 3. Comparing Time Periods: We compared consecutive time periods (2004 and 2022) in terms of the percentage of sand entering or leaving specific parts of the study area. 4. Calculating Change Areas: We quantified the areas where sand ratios increased or decreased between the two time periods. 5. Identifying Threatened Areas: Our study identified regions within the study area that are at risk of sand encroachment. Using mathematical modeling, remote sensing data, and field observations, we derived a statistically significant multiple linear regression equation using the Stepwise Regression procedure. This equation allowed us to estimate sand ratios within the study area using a time series of LANDSAT 8 and 5 satellite images. Additionally, we used spectral and topographic indices as independent variables related to sand ratios. Our findings revealed clear variations in sand quantities moving or infiltrating different locations within the study area during the research period(2004 to 2022). Furthermore, we observed changes in the extent of sand areas between time periods and variations in their spatial distribution. Notably, our study analyzed climatic data on wind speed from surrounding weather stations for all months over a span of more than ten years. The months of May, June, July, August, and September were particularly significant in terms of sand movement. In this study, the threatened areas prone to sand encroachment within the study area were identified by examining several factors influencing sand movement and dune formation. Through an overlay analysis of all these influential factors related to sand movement and transport within the study area, they were classified into five levels of risk severity. The following distribution of risk areas was observed: 1. Very High-Risk Displacement and Sand Movement Areas: These areas accounted for approximately 32.68% of the study area. 2. High-Risk Displacement and Sand Movement Areas: These areas constituted approximately 48.87% of the study area. 3. Low-Risk Displacement Areas: These regions covered about 18.21% of the study area. The classification considered the varying degrees of danger associated with each factor.
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This bibliographic record has been provided by National Centre for Agro. Inform. and Documentation, Ministry of Agriculture and Agrarian Reform