Dune Pattern interrupted by ephemeral drainages and human activities, on the northern Ordos Plateau in China

Abstract

Dune patterns are considered a representation of the desert landscape, and their formation and evolution are affected by climatic conditions and regional differences in the sedimentary environment. High-resolution satellite images from 2007 to 2021 were used to quantitatively analyze the spatiotemporal variation of pattern parameters on the northern Ordos Plateau in China by using the dune pattern analysis method. Combined with meteorological factors and land use changes, this analysis provides insight into the dynamic change of dune patterns and the main controlling factors of dunes evolution. The results show that ephemeral drainages and roads developed in the plateau interrupt dune agglomeration downwind without significant changes in the pattern parameters from west to east and without obvious spatial variation trend of parameters in each area separated by linear obstacles. In the past 14 years, the crestlines of the sampled dunes have always been NE-SW and NNE-SSW, with a counterclockwise deflection that gradually occurred with time. The crestline length and dune height showed a decreasing trend, while the dune spacing and defect density showed an increasing trend. After 2012, a significant rise in precipitation and a drop in wind speed contributed to vegetation recovery, promoting the transformation of barchan dunes to parabolic dunes and breaking the original self-organization evolution of dunes. Therefore, the spatiotemporal evolution of dune pattern in the northern Ordos plateau is driven by natural and human factors and differs from that in the hinterland of mobile deserts.