The phenomenon of singing sand dunes in the Chinese desert.

The scattered sand dunes in the Kumtag Desert near Dunhuang city produce a distinctive sound when the wind blows through them.

The singing sand dunes in Dunhuang. Photo: Lonely Planet

The singing dunes vary in size, with the highest peak reaching 1,715 meters. When viewed up close, they even display a rich array of colors, from yellow and white to green and black. While not unique to Dunhuang, the singing dunes in this region were found along the Silk Road, a vital trade route between Central Asia and Europe for 1,500 years, starting in the 2nd century BC.

The quality of the sand grains is just one factor in what makes sand dunes sing. Comprising a range of fine to medium-sized grains, the size of the sand allows them to move and interact better. Combined with their shape, this creates resonance and different frequencies. Round and smooth grains produce a more pleasant sound. The shape of the sand dunes also contributes to the sound. The slope of the dunes affects the degree of interaction between the grains. Additionally, suitable wind conditions are needed to blow enough sand to produce sound. In strong winds, the dunes produce a loud rumbling sound, but in gentler conditions, the sound is more melodious.

The surrounding structure is also one of the causes of sound generation and amplification, as hills create air currents that concentrate wind in specific areas around the sand dunes. When the wind blows, the sand grains experience friction, causing the sand layer to vibrate and produce sound. Air pockets between the sand grains can act as resonance chambers, amplifying that sound. Arid climates are another sound-producing factor. This is why singing sand dunes are found in desert environments. Low humidity increases friction between the sand grains, creating sound as they rub against each other. The combination of sand grain vibrations, resonance, and air pockets results in the characteristic sound of sand dunes.

Besides Dunhuang, singing dunes have also been found in Inner Mongolia, Xinjiang, Gansu, and Ningxia. The Namib Desert in Namibia and the Mojave Desert in California also have similar dunes. Researchers closely monitor signs of erosion and the impact of traffic on the dunes. Despite the large number of tourists, each night the desert wind erases all traces, restoring the dunes to their original pristine state.

An Khang (by IFL Science )

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