Influence of the Surface Temperature Evolution over Organic and Inorganic Compounds on Iapetus

Round 1

Reviewer 1 Report

Thank you very much for an interesting study of the changes to the surface of Iapetus. This is an intriguing object and understanding it is important for understanding the way in which surface composition is altered due to internal and external processes and how organic and inorganic material behave differently.

However, the manuscript falls far short of a scientific publication. Firstly, you need to describe in much more detail how the simulation is performed – someone else will need to be able to reproduce what you did. You also need to better justify the starting conditions. Also, what happens to the albedo? You need to show (not speculate) how, in your simulation, the species considered here migrate from the dark to the bright side.

Furthermore, the writing is often difficult to understand because of linguistic problems but also because you do not make yourself clear. I highlight many instances of this, but the text needs to be thoroughly checked and corrected by a language editor.

Substantial additions and rewriting are required before the manuscript can be reconsidered for publication.

Detailed comments:

Line 40: it is not clear what you mean by “fast”, in “fast exosphere”.

Line 48: “in this regard” introduces a contrasting explanation (internal versus exogenous), so perhaps “On the other hand” would be more appropriate.

Line 57: give a reference for the 23% value.

Line 74: what “variation in temperature” do you have in mind? A variation across the surface? Or a variation in time?

Line 74: it is not clear what you mean by “concentrating” an “energy budget”.

Line 90: “The conservation of the equations” -> “The equations of the conservation”

Line 92: “in e.g.” -> “e,g,”

Line 93: justify the choice of initial temperatures of 90 and 130 K, respectively.

Line 100: it is not clear what you mean by “sensible heat flux”.

Equation 1: explain the symbols and the different terms, and list the adopted values for the coefficients.

Explain how equation 2 is used in conjunction with equation 1 (note that Da doers not appear in equation 1).

Lines 107/108: it is not clear what you mean by “integral collision”

Lines 108-122: the description of the “data mining” procedure is very vague. Not only is the procedure unclear, also it is not explained why this is done.

Line 114: “In base” – do you mean “Basically”/

Lines 131/132; the sentence “The atmosphere thickness model was assumed to play a dominant role in the heat distribution” seems totally unconnected to the rest of this paragraph, and in any case it is unclear what this “atmosphere thickness model” entails.

Line 153: the atmospheric structure is “constructed”, but nowhere do you explain how this is done.

Line 155: nowhere do you explain how the “simulation” is performed.

Line 160: it is not clear what you mean by the “effects of the maximum temperature were neglected”.

Line 160: “like the segregation” -> “like resulting from the segregation” (?)

Line 162: “could influence” – aren’t you simulating this? Hence, can’t you be more certain about what’s happening?

Line 165: why does the dark side absorb only 58% more radiation than the bright side, when their albedos are 0.04 and 0.39, respectively (almost an order of magnitude different0?

Line 166: “percent of absorption” needs to be written more accurately.

Figure 1, caption: you state that the temperature increments are not substantial, but 40% increase for the leading side is very substantial, and even 10% for the trailing side is not negligible.

Line 178: albedo of “0.38” -> “0.39”?

Line 181: “scattering of” – do you mean “scattering by”?

Line 183: it is not clear what you mean by “deeper on surface”.

Line 185: what do you mean by “their differences”?

Lines 185-187: I don’t understand how the dominance of methane and water ice on TNOs can be invoked to explain why the bright side of Iapetus results from the diffusion of these species.

Line 206: what do you mean by “mass rate”?

Figure 2: obviously there needs to be a balance between the energy that goes in and the energy that goes out. Since you determine a low stellar radiation influx, what is the energy source for the much higher thermal radiation flux?

Line 222 / figure 3: you refer to figure 3 for the diffusion coefficients but that figure shows reflectance spectra. What is the relevance of the figure for the diffusion coefficients, or anything else for that matter? Also, it appears this is not your own figure, so I am seriously doubting this can or should be published here.

Line 234: you probably do not mean “virtuous”…

Line 292: is “Murchie and Head” a citation? In that case it is typeset incorrectly.

In the conclusions section you refer to figure 3 (again) being used for your simulation, but how? Likewise, you introduce something completely new, “DEM” which you do not explain at all, and it is unclear what figure 4 is trying to show. These elements of your work need to be properly described in earlier sections, not in a conclusions section.

see above

Author Response

Dear reviewer.

I attach you the authors’ response to the review comments.

Best regards.

Corresponding author.

Author Response File: Author Response.pdf

Reviewer 2 Report

My comments are in the  report. Extensive rewriting to add clarity can make this a better paper.

Comments for author File: Comments.pdf

Author Response

Dear reviewer.

I attach you the authors’ response to the review comments.

Best regards.

Corresponding author.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments for author File: Comments.pdf

Author Response

Dear Reviever.

I attach you the Authors’ response to the review comments

Thanks and best regards.

The corresponding author

Author Response File: Author Response.pdf

Reviewer 2 Report

Thank you for revising.

English is pretty good.

Author Response

Dear Reviever.

I attach you the Authors’ response to the review comments

Thanks and best regards.

The corresponding author

Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

Equation 6 still has  e_sat (T_s)  but equation 4 has it as  e_sat . T_s Which is it? At least one of them needs to be corrected.

Check and correct carefully the many inconsistencies in upper/lower-case and punctuation across equations 3-6

no

Author Response

Dear Reviewer.

I attach you the Authors’ response to the review comments

Best regards 

Corresponding author

Author Response File: Author Response.pdf