Grain-size composition of the surface sediments in Chinese deserts and the associated dust emission

Chinese deserts are one of the essential source areas for global dust emission, and the intensity of dust emissions varies significantly depending on the grain-size composition of sediments, wind force, and vegetation coverage. To obtain complete and accurate information on the grain-size compositions of the surface sediments in these deserts and to assess the contribution of Chinese deserts to Asian dust emission, we systematically collected surface sediments from 12 deserts in northern China, and analyzed their grain-size composition. We also calculated dust emissions from 2010 to 2019 based on the sand transport rate and clay content. The mean grainsize of surface sediments was 2.34 phi, and the clay and silt contents were only 0.6 and 6.7%, respectively. The Taklimakan Desert had the finest surface sediment, with a mean grain-size of 2.75 phi, whereas the Kumtag Desert had the coarsest sediment, with a mean grain-size of 2.00 phi. The total annual dust emission of the Chinese deserts from 2010 to 2019 was 70.6 Tg y-1. The Taklimakan Desert in the western region, the Badain Jaran Desert and the adjacent Tengger and Ulan Buh deserts in the central region, and the Otindag Sandy Land in the eastern region were the greatest contributors to dust emission. These core areas of dust emission are also the regions with the highest dust storm frequency, indicating that the deserts are significant regions for dust storms in northern China and an important surface type for dust emission in China. We found a significant positive correlation between dust emission and dust storm frequency.

Automated summary

Chinese deserts play a significant role in global dust emission, with variations in grain-size compositions of surface sediments contributing to differences in dust emissions. The study highlights the importance of different desert regions in dust emission and their correlations with dust storm frequency.