Gravity Wave Breaking Associated with Mesospheric Inversion Layers as Measured by the Ship-Borne BEM Monge Lidar and ICON-MIGHTI

Round 1

Reviewer 1 Report

Please, see attached document.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer 1,
Please see the attached PDF with our responses

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments on” Detection of Gravity Wave Dissipation via Transient Instabilities in the upper Mesosphere/ Lower Thermosphere (MLT) made by the BEM Monge lidar and the ICON Satellite” by Wing et al. 2021

                                                         

General comment:

This manuscript attempt to address the occurrence of mesospheric inversion layers (MILs) and the role of wave breaking and wind direction reversal in the formation of the MILs. The authors used a multi observational and reanalysis data set to address the above problem. However, there is no connection between the title of the manuscript and the results and discussion. For example, the title reads gravity wave dissipation via transient instability… there is no extensive investigation regarding this. They did not show any wave dissipation or the presence of instability except for the convective instability around 104 km corresponding to the mesopause altitude. Though this study used various data set but the data is not used properly and the arguments are mostly vague. This manuscript should be thoroughly revised before publication. Therefore, I recommend to the Editor for a major revision.

Specific comments:

1. The title of the manuscript should be changed, “detection of mesospheric inversion layers and their causative mechanism”…something like that, or for the current title, the analysis should show the dissipation of waves and instabilities (estimate the convective and dynamical instabilities).
2. Line 6-9, There three data set…of breaking waves. There is not enough evidence for this statement.
3. The introduction should be in the direction of the scientific objective of the manuscript. However, the present introduction is written in a generic manner. There is no information about the previous understanding of the GWs and MILs in the low latitude MLT region, though that is the prime focus of the present study.
4. Line 87, The lower MILs…through interacting with the winds. Remember, the lower MILs are believed to be caused by the planetary waves breaking (e.g. Salby et al. 2002, Ramesh et al. 2014, etc.,)
5. Line 97-98, We also expect that the ….higher altitudes. Is it the vertical or horizontal wavelength?
6. Section 2.1, It is better to give brief information about the location of the observation and corresponding dates.
7. Line 123 MTL. Typo
8. Line 132, the Raman temperatures are used… up to what height?
9. Line 151, could you brief about the warm bias?
10. Line 169, Do the authors think that within 1000 km, the wind and temperatures will be uniform in the MLT region?
11. 172, ground/sea-based measurements. What do you mean here?
12. MLS data is not useful for the MILs or short-period gravity waves study. It can be used only as a background temperature.
13. Lines 180, GRAW. Expand it.
14. What is the interval of radiosonde launching?
15. What is the temporal resolution of the ERA5 data used in the study? Is ERA5 reliable above the stratopause?
16. Section 3.1, Mention the errors in the Rayleigh lidar temperatures above 90 km.
17. Line 230-233, At minimum…15 minutes. This statement is not clear.
18. Line 241, sliding average... Elaborate it.
19. I could not see any E^mass estimation in this study!
20. Line 268-277, please mention the exact altitude of the MILs (altitudes are roughly mentioned here). Before pointing the MILs, first define it, what is the minimum thickness and amplitude of the inversion considered as MILs in this study?
21. Figure 5 is showing only the temperature perturbations, not the MILs, so correct it in the write-up.
22. Mention the vertical resolution of the ICON data.
23. 312, why cannot the authors estimate the static stability every 15 minutes?
24. Line 321, negative N₂ at 104 km, is simply due to the mesopause altitude.
25. Line 324-326, In meteorological convention positive zonal wind, is considered eastward!
26. Line330, easterly…, please use the same conventional term… either eastward or easterly throughout the manuscript.
27. In figure 7, I really wonder about the smooth transition between three different datasets!
28. Line 360, dT/dz, typo?
29. Line 362-363, There is evidence of wave-driven changes. Remember, chemical heating also can change the temperature lapse rate in the mesosphere.
30. In fig. 8, there is no positive lapse rate around the lower MIL altitude on D-3 and D-0?
31. How the wind reversal can cause the MILs?
32. Do the wavelet analysis for all three days and see the variation in the wave activity. Since you have data from the lower stratosphere to the mesosphere, try to see where the waves are coming from?
33. 11, Y label is wrong, correct it.
34. The discussion part needs to be improved.

 

 

Author Response

Dear Reviewer 2,
Please see the attached PDF with our responses

Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript presents the lidar Rayleigh high resolution temperature measurements of the upper mesosphere and lower thermosphere during five consecutive nights. The measurements are correlated with other measurements: wind speeds are measured using radiosondes, winds and temperatures are taken from NASA’s ICON satellite; other data are taken from European Center for Medium-Range Weather forecast or are measured with Sounding of the Atmosphere using Broadband Emission Radiometry or Microwave Limb Sounder instruments.

For the data analysis the authors used mostly a Morlet wavelets method.

As main result the authors observed at about 70 km the creation of a mesospheric inversion layer due to gravity waves breaking in the mean wind.

The results are interesting, the methods are generally well described and the paper is well organized. I recommend publication in Atmosphere after improving some minor points:

1) Although the equation (1) is quite standard I think a citation is required.

2) The readability of the figures has to be improved. The characters are for many pictures at the limit of readability, the difference between red and magenta is hard to notice.

3) On line 360 dT/(dz)^2 is the second derivative? Then it should be written as d^2 T/ dz^2.

Author Response

Dear Reviewer 3,
Please see the attached PDF with our responses

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I agree with the changes made to the text.

I also agree with the justifications for not changing the text in some of the notes.

I think that the manuscript has been
sufficiently improved to warrant publication in Atmosphere (Journal).

Reviewer 2 Report

Thank you for including the suggestions and clarification of the queries.