Barchan dune dynamics in the sand belt between the Badain Jaran Desert and Ulan Buh Desert
The sand belt between the Badain Jaran Desert and Ulan Buh Desert consists of undulating high plains and piedmont banded mobile sands.Using multi-period high-resolution remote sensing images,the moni-toring of the barchan dune in the sand belt was carried out.We selected piedmont zone,main body,north and south sides of the high plains as four typical sample areas of the belt.By extracting and calculating the dune pa-rameters,we analyzed and explored the spatio-temporal variations of dune movement,morphology,sand trans-port fluxes,and their influencing factors.The results showed that the dune movement and morphology in the belt represented different spatio-temporal changes during 2003-2020 due to the differences in topography,wind re-gime and dune scale.The specific results are as follows:(1)The dune movement rate ranged from 2.09 m·a-1 to 40.93 m·a-1,with an average of 12.89 m·a-1.The down slope-moving dunes in the piedmont sand belt have moved faster than those in the high plains.The dune movement rate tended to decrease in the high plains sand belt,and tended to increase in the piedmont belt,with the change of the resultant drift potential(RDP).(2)The dune movement direction was 102°-152°,with an average of 126°,and controlled by the change of strength of pre-vailing wind direction.In the high plains sand belt,the belt shifted to the north and to the south in the piedmont,but both are inconsistent with the resultant sand transport direction.(3)In the process of dune movement,the length of the windward slope tended to increase,the height tended to decrease,and the alternating effect of the primary wind(W)and the secondary wind(NW)makes the southern flank elongation.(4)In the past 20 years,the low dunes have a sand material loss,and the relatively tall dunes have a sand material balance.(5)Consider-ing the width and the dune density of the sand belt,the sand flux of the belt was calculated as 117 t·m-1·a-1,and it is estimated that the Badain Jaran Desert has contributed at least 5.5×105t sand to the Ulan Buh Desert every year.
dune dynamicssand transport fluxbarchan duneBadain Jaran DesertUlan Buh Desert
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