The authors present a very detailed uncertainty analysis regarding space lidar observations of dust and the potential to separate the fine-mode and the coarse-mode fraction of the dust aerosol.

The paper is rather long, and I had the feeling it should be shortened. On the other hand, AMT should cover such long and detailed papers dealing with quality assurance studies.

I have some minor remarks, only.

p1, l37: Improve wording: …the quality of the dust products is justified … What do you want to say? The quality can be good, excellent, poor etc… but what means …. justified?

p2, l9: The research community prefers to denote ‘ice nuclei’ meanwhile ‘ice-nucleating particles (INPs)’

p2, l32: life cycle

p2, l33: One should cite the lidar paper on dust devils and convective plumes of  Ansmann et al., Tellus, 2009, in this context.

p3, l22: ..remote sensing of the atmospheric aerosols. The technique is able……

p4, l36: I would add recent modeling studies of Saito et al. Please check whether these authors also provide  information on size (fine, coarse) dependence  of the dust depolarization ratio.

Saito et al., A Comprehensive Database of the Optical Properties of Irregular Aerosol Particles for Radiative Transfer Simulations, J. Atmos. Sci.,  https://doi.org/10.1175/JAS-D-20-0338.1

Saito, M., Yang, P. (2021). Advanced bulk optical models linking the backscattering and microphysical properties of mineral dust aerosol. Geophysical Research Letters, 48(17), e2021GL095121. 10.1029/2021GL095121

p5, l3: Again, what do you mean? … Section 3 provides justification of the validity…

p5-p18: Section 2 is rather long… Are all the mentioned details needed?

p8, l 27: The definition  of the fine and coarse mode (< and > 1 µm in diameter) should be already given in the introduction, as early as possible.

p10, l5: Please check the two papers of Hofer et al., ACP 2020a, b (Tajikistan lidar observations), and the Hu et al. ACP paper in 2020 (Taklamakan lidar observations).

p12, l10: Mineral particles with diameters >62.5 µm are no longer dust particles. The size of 62.5µm  defines the minimum diameter of the sand particle range.

p14, Figure 3 is rather small.

p14, Table 3, please check and add: Hofer et al. 2020b on depol and lidar ratios, and Hu et al. 2020.

Section 3: Consistency check

Figure 5: This is one of the key figures. Therefore the panels must be larger. I suggest to have two  top panels (a,b), then two center panels (e,f), and finally two bottom panels (d, c).

Figure 6: My spontaneous question was: Who is right? AERONET or CALIOP? The correlation line in the left panel (a) does not provide a clear answer. The agreement between AERONET and CALIOP (scattered data cloud) is good. And, one should not forget: There is always a non-dust fine-mode contribution to the AERONET AOT.

The right panel shows good agreement as well when keeping the impact of the uncertainty in the lidar ratio assumption into consideration.

Figure 8: The 1064 nm particle or volume depol ratio is quite high. Above 30%! Other observations at 1064nm  did not show that, except observations (e.g. of Burton et al.) directly in the dust source region. Also in the marine boundary layer the depol ratio is likewise high. It is summer (August) and the marine layer should not be contaminated with dust so much. Did you check the quality of the CATS depolarization measurement?

p25, l5, I cannot find Eqs.(13) and (14)!

p25, l10: Eq.(10) and (11) are now Eq.(9a) to (9c)?

Figure 9: The in situ observations in Fig. 9d show a pronounced fine mode, in contrast to the lidar fine-mode observations. Maybe this is an indication for the dominating anthropogenic pollution from Africa. The in situ observations provide the total fine mode mass concentration. Is there an option to even distinguish fine dust from fine-mode aerosol pollution in the in situ observation?

p26, l15-l31: Again the discussion of the fine mode aerosol is difficult. It remains tricky to find a good solution for the different contributions of fine-mode pollution and fine-mode dust to the overall fine mode aerosol fraction.

Section 4: Three dimensional distribution …

p31, l25: India is meanwhile the most polluted sub-continent. So, again it will be complicated to get a clear picture in terms of coarse-mode dust, fine-mode dust, and dominating fine-mode anthropogenic pollution. The separation of coarse-mode dust is the most straightforward approach. But, then the discussion becomes quite speculative.

p31, l42: Why should  only the coarse-mode dust fraction show a wave-like seasonal cycle? The fine-mode dust fraction will show the same, I guess.

p32, l3. Why should long range transport over the continent take place in the free troposphere, only, and not in the PBL as well? Over the oceans, this seems to be the case (dust transport in the free troposphere above the colder marine boundary layer). But over the continents? There is ONE dust layer, to my opinion, from the surface up to probably 3-4 km height (up to the PBL height over subtropical India). Figure 12c corroborates my opinion.

Figure 12e vs 12f is confusing! There is a relatively high coarse-mode dust fraction above 2 km height, but not a high fine-mode fraction. What is the reason for this contrast? And the opposite is found for the near surface heights (up to 1.5 to 2 km). The fine-mode anthropogenic aerosol should clearly dominate in the highly polluted boundary layer.

p33, l9-l29: Keeping my question just mentioned in mind, I find the discussion quite speculative.  Please, provide a bit more careful, more hypothetical debate.