The authors designed a novel technique in wind tunnel to measure the entrainment rate of various particle sizes under different flow conditions. They show that quasi-convective turbulence increases the surface shear stress and hence substantially enhances the entrainment of sand and dust particles. It is a very novel experiment design, and the results are very enlightening.

Comments:

The authors analyzed the power spectrum and PDF of the quasi-convective turbulence, and believed it is similar to convective eddies in atmospheric boundary layers. But from the generation way, the quasi-convective turbulence is more like a kind of coherent structure observed in the atmospheric boundary layer (Liu and Zheng, 2021). Please give some explanation and discussion.

In line 119-123, how to get z0ABL?

In line 141, should “z<0.2m” be “z>0.2m”?

Reference

Liu, H. Y. and X. J. Zheng, 2021. Large-scale structures of wall –bounded turbulence in single- and two-phase flows: advancing understanding of the atmospheric surface layer during sandstroms. Flows, 1 E5.