Dear Authors!

Thank you for upload your responses to the Editor and reviewers comments. I am going to send the manuscript again to the reviewers in order to hear the opinion from them.

Best regards,

Igo

Dear Authors!

Thank you for revise the manuscript. I agree with the both reviewers that your paper has substantially been improved compared to the first version. However, I agree with reviewer #2, as well, that one of the main topics was not addressed properly, i.e., I am not convinced of the negative correlation between the solar activity and occurrence of multiple layers. Please, revise the manuscript in order to clarify it.

Reviewer #1 has pointed out that several English mistakes remain in the manuscript. Please, revise it for the final version and highlight the all of the modification.

Best regards,

Igo

Dear Dr. Ge et al.,

Thank you for revise the manuscript again, In my opinion, it is worthy to be published in the Annales Geophysicae. Congratulations for the work. I have few points as following to be corrected in the final version of the manuscript.

Best regards,

Igo
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Pg 1, line 28: …of the near Earth…;?
Pg 2, line 2: PMSEs have been -> PMSE has been
Pg 2, lines 5-6: “…half wavelength of the radar..”
Pg 2, line 27: please, type the meaning of “OR” in the introduction as well.
Pg 3, lines 23-25: Please, rewrite the main goal of the work since the conclusions do not support the stated objetive.
Pg 4, line 5,:…Table 1 for…
Pg 4, line 6: has run -> ran
Pg 5, line5: and visit www.eiscat.se…
Pg 5, line 5: In this case, based on the unit, I guess it is electron concentration instead of electron density, is not it?
Pg. 5, line 10: use “…see Appendix A, Table A.2 of Qiang Li (2011)” instead of “…and Qiang Li (2011) (see Appendix A Table A.2).“
Pg. 5, line 11: meteors -> meteor
In my opinion, subsections 4.1 and 4.2 are the methodology and not results as named. What do you think?
Sometimes you write “double-layer”, sometimes you write “double layer”. Please try to use the same pattern for all cases (same comment for mono- and tri-layers).
Pg 11, line 1, please delete “a” before certain
Please, enlarge symbols and legend of Figure 9.