Abstract
Mega-dunes in the lake group area of the Badain Jaran Sand Sea, China, are generally taller than dunes in the non-lake group area. This spatial distribution of dune heights may provide a new perspective on the controversy regarding the dunes’ formation mechanism. In this study, we calculated the relative heights and slopes of individual dunes based on a digital elevation model, and we confirmed the height distribution of abnormally tall dunes in the lake group area of the sand sea. It was also found that slopes of more than 10° in the lake group area are more common than those in the non-lake group area. Based on meteorological observations, coupled with the measurement of water content in the sand layers, we propose a conceptual model demonstrating that moisture exchange between the lakes and soil via non-rainfall water will humidify dune slopes and form a more favorable accumulation environment for aeolian sand, thus increasing dune heights. Although long-term observations are yet to be carried out, the present study can be used as evidence for understanding the basis of dune formation in the lake group area and assessing groundwater utilization in deserts.
Highlights
The formation and evolution of sand dunes are related to various factors such as wind conditions [1], sand supply [2], topography [3], geological constraints [4], and the depth of the atmospheric boundary layer [5]
The formation of mega-dunes has long been a topic of interest in aeolian sand geomorphology due to their relationship with the natural limit of maximum dune height and their importance in understanding and verifying the mechanism of dune morphological evolution [6,7,8,9]
Mega-dunes in the Badain Jaran Sand Sea of Northern China have been identified as being the tallest in the world [6,10,11,12], but the reason for the tallest dunes being found adjacent to the lakes is currently unclear, and more work needs to be conducted on the interaction of lakes and dunes
Summary
The formation and evolution of sand dunes are related to various factors such as wind conditions [1], sand supply [2], topography [3], geological constraints [4], and the depth of the atmospheric boundary layer [5]. This study proposes an algorithm for calculating dune heights and slopes using a digital elevation model (DEM), which was applied to the Badain Jaran Sand Sea. The location and area of the lakes were obtained through visual interpretation, and the spatial distribution pattern of dune morphology and statistical relationship between the morphological indexes and total lake. Based on meteorological observations and water content measurements of dune surface layers in different basins, a conceptual model of dune growth incorporating the lake-dune pattern was proposed to explain the occurrence of the tallest dunes in the lake group area of the Badain Jaran Sand Sea
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