The Badain Jaran Desert is located in the arid region of northwest China, and is a unique landscape characterised by more than 140 lakes as well as extensive megadunes (Figure 1), including the highest dune in the world. In 2009, the United Nations Educational, Scientific and Cultural Organization approved the Badan Jaran Desert Scenic Area, the Tengger Desert Scenic Area and Juyanhai Scenic Area as the "Alxa Desert World Geopark".

Since the beginning of the 20th century, the unique natural landscape of Badain Jaran Desert has received considerable research attention, especially whether the about 90mm of atmospheric precipitation in the region can serve as a source of water for many lakes have been the focus of controversy.

A recent research work revealed that atmospheric precipitation in the Badain Jaran Desert recharges the lake water.

This research work, entitled "The discovery of surface runoff in the megadunes of Badain Jaran Desert, China, and its significance", coauthored with Jingbo Zhao, Yandong Ma, Xiaoqing Luo, Dapeng Yue, Tianjie Shao and Zhibao Dong, scholars at Shaanxi Normal University, was published in the Science China Earth Sciences, No. 4, 2017.

The researchers obtained a number of important new discoveries through field surveys in the Badain Jaran Desert, such as physical and chemical deposits produced by surface runoff on the slopes of megadunes, rarely-seen infiltration-excess surface runoff in the megadune depressions and spring streams at the base of megadunes, and used electron microscopy, energy spectrum analysis, infiltration experiments, moisture content determinations and grain-size analysis to study the mineral and chemical composition of the runoff precipitates, and grain-size of the deposits associated with the runoff, together with the hydrological balance in the megadune area, and the atmospheric precipitation mechanism responsible for groundwater recharge and for supplying water to lakes.

Several lines of evidence, such as the physical and chemical deposits resulting from shallow subsurface runoff, spring streams, infiltration-excess runoff, and gravity capillary water with a moisture content of 3%-6%, demonstrate that the hydrological cycle in this region is characterized by atmospheric precipitation-soil water-groundwater-surface water conversion model (Figure 2), that is, atmospheric precipitation reaches the base of the megadunes through infiltration and subsequently becomes groundwater and lake water.

The result of this study is of great scientific significance in explaining the source of lake water in the Badain Jaran Desert, is of great practical significance to the scientific utilization of groundwater resources in this region, and is of great reference value in research on the hydrological cycle, including groundwater recharge conditions and recharge mechanisms, in desert region.

J. Zhao, Y. Ma, X. Luo, D. Yue, T. Shao, Z. Dong, "The discovery of surface runoff in the megadunes of Badain Jaran Desert, China, and its significance," Sci. China Earth Sci., (2017) 60(4): 707-719. doi:10.1007/s11430-016-9019-2

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