scholarly journals Response to anonymous referee #1’s interactive comment on the manuscript “Dependency of Particle Size Distribution at Dust Emission on Friction Velocity and Atmospheric Boundary-Layer Stability”

2020 ◽  
Author(s):  
Jie Zhang
Keyword(s):  
Boundary Layer ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Atmospheric Boundary Layer ◽  
Size Distribution ◽  
Friction Velocity ◽  
Dust Emission ◽  
Boundary Layer Stability

scholarly journals Dependency of Particle Size Distribution at Dust Emission on Friction Velocity and Atmospheric Boundary-Layer Stability

2020 ◽  
Author(s):  
Yaping Shao ◽  
Jie Zhang ◽  
Masahide Ishizuka ◽  
Masao Mikami ◽  
John Leys ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Particle Size ◽  
Probability Distribution ◽  
Particle Size Distribution ◽  
Atmospheric Boundary Layer ◽  
Size Distribution ◽  
Friction Velocity ◽  
Boundary Layer Stability ◽  
Surface Shear Stress ◽  
The Mean

Abstract. Particle size distribution of dust at emission (dust PSD) is an essential quantity to be estimated in dust studies. It has been recognized in earlier research that dust PSD is dependent on soil properties (e.g. whether soil is sand or clay) and friction velocity, u*, a surrogate for surface shear stress and descriptor for saltation bombardment intensity. This recognition has been challenged in some recent papers, causing a debate on whether dust PSD is invariant and the search for justification. In this paper, we analyze dust PSD measured in the Japan-Australian Dust Experiment and show that dust PSD is dependent on u* and on atmospheric boundary-layer stability. By simple theoretical and numerical analysis, we explain the three reasons for the latter dependency. First, under similar mean wind conditions, the mean of u* is larger for unstable than for stable conditions. Second, u* is stochastic and its probability distribution profoundly influences the magnitude of the mean saltation flux due to the non-linear relationship between saltation flux and u*. Third, in unstable conditions, turbulence is usually stronger, which leads to higher saltation-bombardment intensity. This study confirms that dust PSD depends on u*, and more precisely, on the probability distribution of u*, which itself is stability dependent. We restate that for a given soil, finer dust is released in case of stronger saltation.

scholarly journals Dependency of particle size distribution at dust emission on friction velocity and atmospheric boundary-layer stability

2020 ◽  
Vol 20 (21) ◽  
pp. 12939-12953
Author(s):  
Yaping Shao ◽  
Jie Zhang ◽  
Masahide Ishizuka ◽  
Masao Mikami ◽  
John Leys ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Particle Size ◽  
Probability Distribution ◽  
Particle Size Distribution ◽  
Atmospheric Boundary Layer ◽  
Size Distribution ◽  
Turbulent Flows ◽  
Friction Velocity ◽  
Surface Shear Stress ◽  
Surface Shear

Abstract. Particle size distribution of dust at emission (dust PSD) is an essential quantity to estimate in dust studies. It has been recognized in earlier research that dust PSD is dependent on soil properties (e.g. whether soil is sand or clay) and friction velocity, u∗, which is a surrogate for surface shear stress and a descriptor for saltation-bombardment intensity. This recognition has been challenged in some recent papers, causing a debate on whether dust PSD is “invariant” and the search for its justification. In this paper, we analyse the dust PSD measured in the Japan Australian Dust Experiment and show that dust PSD is dependent on u∗ and on atmospheric boundary-layer (ABL) stability. By simple theoretical and numerical analysis, we explain the two reasons for the latter dependency, which are both related to enhanced saltation bombardment in convective turbulent flows. First, u∗ is stochastic and its probability distribution profoundly influences the magnitude of the mean saltation flux due to the non-linear relationship between saltation flux and u∗. Second, in unstable conditions, turbulence is usually stronger, which leads to higher saltation-bombardment intensity. This study confirms that dust PSD depends on u∗ and, more precisely, on the probability distribution of u∗, which in turn is dependent on ABL stability; consequently, dust PSD is also dependent on ABL. We also show that the dependency of dust PSD on u∗ and ABL stability is made complicated by soil surface conditions. In general, our analysis reinforces the basic conceptual understanding that dust PSD depends on saltation bombardment and inter-particle cohesion.

scholarly journals Spectral particulate attenuation and particle size distribution in the bottom boundary layer of a continental shelf

2001 ◽  
Vol 106 (C5) ◽  
pp. 9509-9516 ◽  
Author(s):  
Emmanuel Boss ◽  
W. Scott Pegau ◽  
Wilford D. Gardner ◽  
J. Ronald V. Zaneveld ◽  
Andrew H. Barnard ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Continental Shelf ◽  
Size Distribution ◽  
Bottom Boundary Layer ◽  
Bottom Boundary
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