Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： Barchan and parabolic dunes can be transformed into each other and coexist in the same area, resultingin a unique landscape in which typical barchan dunes coexist with embryonic barchan and parabolic dunes. It ishelpful to understand the causes of their formation and execute targeted desertification prevention and controlprojects after studying their spatial distribution, morphological characteristics, and migration. Based on the Esrihistorical image service (World Imagery Wayback), the morphological parameters of the dunes in the coexistencezone of the barchan and parabolic dunes, west of Hunshandake Sandy Land, were extracted in three periods:January 15, 2008, June 4, 2011, and September 20, 2016, and the direction and velocity of the dune migrationwere calculated. The results indicate that typical barchan dunes are concentrated in 15 areas related to the drylake bed in the western part of the sandy land, whereas embryonic barchan and parabolic dunes are sequentiallydistributed around the periphery of the dry lake bed. The appearance of the dry lake bed was a key factor in thedevelopment of the typical barchan dunes in the Hunshandake Sandy Land. Therefore, more attention should bepaid to the desertification caused by the lake drying up. The analysis of morphological parameters of sand dunesin the fifth zone, where the co- existence of barchan and parabolic dunes is typically found, indicates that thetypical barchan and embryonic barchan dunes significantly differ from embryonic parabolic dunes. Thecorrelation analysis between the morphological parameters of sand dunes indicates that toss slope length, leeslope length, and bottom area are inherited from the barchan to parabolic dunes, with horns experiencing thegreatest changes during this process. Furthermore, the migration directions of the three types of dunes are almostequal but have varying migration velocities, as well as the factors that affect the migration of sand dunes. Themost significant impact on the embryonic parabolic dunes, whose vegetation cover is relatively high, was thevegetation cover, whose variation was consistent with that of NDVI during the same period. The most significantimpact on the typical barchan and embryonic barchan dunes, whose vegetation cover is relatively low, was windspeed, whose variation was consistent with that of DP and RDP during the same period. Additionally, otherfactors, including terrain, sand sources, and human activities, can influence the morphology and migration ofbarchan-parabolic dunes.
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