Abstract:

The coexistence of barchan and linear dunes is common in deserts across China and elsewhere. Previous studies have largely focused on either areas where both dune types coexist （coexisting regions） or regions dominated solely by barchan dunes （typical regions）. However， a systematic comparison between these two landscape types is lacking， hindering a comprehensive understanding of barchan dune evolution under contrasting environmental settings. Here， we investigate barchan dunes from 12 coexisting regions and 7 typical regions in China. We analyzed dune morphology and the associated wind regimes using high-resolution Google Earth imagery and ERA5 reanalysis data. Our results reveal that： （1） Barchan morphology differs significantly between the two region types. In coexisting regions， dunes are smaller and plumper， with "plump" barchans accounting for over 50% of the population and "slender" forms being the least common. In contrast， typical regions are dominated by "normal" shaped barchans， with the proportions of other morphological types showing only minor differences. （2） The wind regimes also differ markedly. Although both regions are classified as low wind energy environments， coexisting regions exhibit higher drift potential， higher mean wind speed， greater directional variability of sand-moving winds， and a wider range of wind direction variability. The corresponding wind regimes are primarily obtuse bimodal and wide unimodal types. （3） These morphological differences are strongly influenced by wind direction variability and substrate salt cementation. Additionally， the partitioning of sand availability between dune types may also contribute to the smaller dune size observed in coexisting regions. This comparative study of dune morphology and wind regime characteristics refines our understanding of the relationship between barchan dune morphometry and its developmental environment， providing a foundation for future numerical simulations of aeolian landforms.

Key words: barchan dune, dune coexistence, dune morphology, wind regime