Turbulence factors for threshold velocity and emission rate of atmospheric mineral dust

Based on the recent observations, which reveal more details of the turbulence effects on particle mobilization (dust emission), and the assumption that the friction velocity u* is the velocity scale in the saltation layer, this paper analyzes the mechanism of turbulence effects on particle mobilization and concludes that turbulence decreases the threshold friction velocity u*t, or the threshold wind velocity ut, and increases the horizontal mass flux q, or the vertical flux (the dust emission rate) f. To mathematically describe the turbulence effects, two factors, both are functions of the turbulence intensity i, are derived, they are: and Tβ(i)=(1+3βi+3i2)/2. Tα(i) is used to amend the threshold friction velocity u*t (or the threshold wind velocity ut) while Tβ(i) is used to amend the horizontal mass flux q (or the dust emission rate f). The two constants in the turbulence factors are estimated by wind tunnel experimental data to be α=2.5 and β=8.7.