Dust-sized fractions from dustfall and physical weathering in the Gobi Desert

Changes in the sediment availability in the Gobi Desert are not well estimated under current climate and environmental conditions. Additionally, the contributions of dustfall and dust-sized fractions produced by physical weathering in the Gobi Desert and their significance on gobi surface equilibrium are still poorly understood. The objective of this study is to quantify the amounts of dust-sized fractions deposited via dustfall and produced by physical weathering in the Gobi Desert and to evaluate the roles of these two processes in maintaining the gobi surface equilibrium. Physical weathering experiments and dustfall collections are conducted from 20th October 2017 to 20th October 2018 in the Ala Shan Gobi, a representative area of the Gobi Desert in Central Asia. The experimental results showed that dustfall on Gobi Desert is 1093 g m(-2) , simultaneously 944 g m(-2) of the dust-sized fractions ( < 63 mu m in diameter) are deposited, and at least 149 g m(-2) of dust-sized fractions are re-emitted from the gobi surfaces. Without considering other dynamics, the results show that the Gobi Desert is both a potential dust source area and a typical source-to-sink region, with deposition rate being greater than the erosion rate. Under current climate and environmental conditions, without fine particles replenished by fluvial processes, the dust deposition and dust-sized fractions, produced by physical weathering, may be the key dynamics affecting Gobi Desert surface equilibrium.