|This revised manuscript is much improved in both content and presentation. There is one larger issue that I want to raise and a number of grammatical modifications to suggest.|
As noted in the author responses, the choice of hexagonal columns, plates, bullet rosettes, and droxtals was simply to provide a sense of different optical properties to compare with their new particle, the Voronoi ice habit. The ice habit comparison is featured in Figures 4, 5, and 6. I think this paper would make a much larger scientific contribution if the droxtal was replaced with an aggregate of solid columns, as is used later in the manuscript. Here’s my argument for doing so. First, the droxtal was promoted initially as an idealized small circular particle to represent the smallest (<10-20 micron) particles at the top of the coldest ice clouds. It was never meant to be used for larger particles as in this paper and is an unrealistic choice for comparisons. Second, the CERES team uses a roughened solid hexagonal particle for their ice cloud retrievals and flux calculations, while the MODIS team now uses an aggregate of solid columns for the Collection 6 cloud products (reference: Holz et al., Resolving ice cloud optical thickness biases between CALIOP and MODIS using infrared retrievals, Atmos. Chem. Phys., 16, 5075-5090, 2016, doi:10.5194/acp-16-5075-2016). If the goal of this paper is to decide upon a model to use with the GCOM-C SGLI satellite sensor, then a proper comparison (and an important one) would be to compare the suggested model (e.g., Voronoi) with the roughened column used by CERES and the roughened aggregate used by MODIS. Basically, my suggestion is to replace the droxtal with the aggregate of solid columns.
page 2, line 11: there’s a “pi” symbol after the word “subsequently” for whatever reason.
page 4, line 3: …using the same micro-physically consistent habit mixture model throughout the spectrum—> …using a habit mixture model based on comparisons with microphysical measurements throughout the spectrum…
page 4, line 6: the relation between —> the relationship between
page 5, line 10: size parameter is first mentioned here, but the definition is provided on line 20. Suggest moving Equation 1 to where size parameter is first mentioned.
page 6, line 5: change “is used” to “are used” because datum is singular; data are plural.
page 6, line 7: a proper reference for the thousands of size distributions is this reference:
Heymsfield, A. J., C. Schmitt, and A. Bansemer, 2013: Ice cloud particle size distributions and pressure dependent terminal velocities from in situ observations at temperatures from 0˚ to -86˚C. J. Atmos. Sci., 70, 4123-4154.
page 7, lines 27-28 and Figure 2: do the authors have any insight as to why there are 3 large peaks in Figure 2b?
page 9, lines 2-3: Is the criterium for selecting the optimal habit a value of the SAD near zero or simply a minimum value of the SAD? How much of the time is the minimum value near zero?
page 9, line 15, discussion of Figure 4: I am puzzled by the results for the asymmetry factor - my experience is that the asymmetry factor increases monotonically with size parameter (but since these results are for a fixed wavelength, the results are really increasing with particle size). Do you have any insight as to why the asymmetry factor does not increase monotonically with particle size?
page 9, line 18: suggest rewording: “the value decreases when size parameter is increasing” to “the value decreases with increasing values of the size parameter”
page 9 line 24: Voronoi habit —> Voronoi habits
page 10, line 21: I’ve read this sentence many times and cannot make sense of it - please reword: “The SRF and TRAD for all size of particles with droxtal model are largest in the all ice particle models”
page 11, one 6: air bubbles and distortion is most efficient —> air bubbles and distortion have lower SAD values than models with distortion only. (Do I have the sense of this right? If not, please reword this sentence to make it more understandable)
page 11, line 20: This sentence is awkward - please reword as it could be interpreted more than one way: “However, that for the Voronoi model is slight smaller than for the other models…”
page 11, lines 21-22: But it seems to me that the Voronoi particle seems to have a larger TRAD than the ensemble model.
page 12, line 26-28: This sentence is long and awkwardly worded. Basically it appears to me that the results of the SAD analysis indicate that the Voronoi particle has the scattering characteristics that are useful for retrievals, e.g., agreement with POLDER/PARASOL polarized reflectances, a low asymmetry parameter, and a smooth phase function. This helps to justify use of this particle for the GCOM-C mission.
About the figures, a general comment: please increase the font size for labels on the figure axes - the labels use small letters that will only decrease further in the publication. Also, it helps to use a font like Arial, Palatino, or Helvetica rather than a font like Times Roman. Second, help the reader out by increasing the amount of information in the captions. For example, in Figure 4, there is little information in the caption. What is As, for example (I think it’s single scattering albedo) - why not use SSA rather than As? Define what “g” and Qext represent in the caption.