Spatiotemporal Analysis of Sand Dune Dynamics: A Case Study from Southern Afghanistan

Abstract

The annual movement of sand in arid and semi-arid regions poses significant environmental and socio-economic challenges. This study focuses on a region in southern Afghanistan, characterized by landscapes where sand dynamics have led to notable land degradation. Arid and semi-arid zones constitute nearly half of Afghanistan's total land area, predominantly located in the southern and western regions. Due to the absence of historical aerial imagery, this research utilizes Google Earth satellite images spanning from 2014 to 2024 to analyze spatial changes in sand dune coverage. In light of limited meteorological infrastructure, specifically the lack of local weather stations and anemometers the study employs wind direction data derived from NASA's MERRA (Modern-Era Retrospective Analysis for Research and Application) reanalysis database. This dataset, known for its approximately 90% consistency with observed climate data, was processed using MCIDAS-V software to generate regional wind direction maps. Furthermore, Geographic Information System (GIS) tools were used to delineate sand dune extents by constructing polygons around the affected areas, enabling precise area calculations. The results indicate significant changes in the spatial distribution of sand dunes over the ten-year period. The primary factors driving the reduction and transformation of sandy areas include the expansion of agricultural lands and increasing construction activities in nearby rural settlements. Additionally, in some locations, sand encroachment aligned with prevailing wind directions has adversely impacted agricultural zones. This study highlights the urgent need for sustainable land use planning and dune stabilization efforts in vulnerable dryland regions.