Dust emission in farmland caused by aerodynamic entrainment and surface renewal

Abstract. Mineral dust emission is an important physical process related to gas-particle interaction and soil moisture temporal change, which is crucial on global circulation patterns and biogeochemical cycles. The existing dust models are usually semi-empirical functions and far from reliable prediction of dust emission rate ignoring the different phases in dust emission. Here, a dust emission model combined with aerodynamic entrainment and surface renewal mechanisms is established to simulate the physical phased dust emission in farmland. We use a soil moisture transport module to simulate the temporal soil surface moisture, and a simple and feasible scheme to calculate the amount of free grains exposed on soil surface. The model reproduces three typical phases of dust emission: aerodynamic entrainment, dry soil saltation and surface renewal, in which soil moisture is the dominating limiting factor and the dust emission rate remains low. Results show that our model is an effective method to predict the dust emission rate.