Seasonal Variation of Stratospheric Gravity Waves in the Asian Monsoon Region Derived from COSMIC-2 Data
Round 1
Reviewer 1 Report
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Comments for author File: 
Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
The revised manuscript describes an important study, describing quantitative EP flux with season. I especially appreciate the inclusion of the references to the study of Forbes and Dunkerton regarding the explanation of the seasonal variation of tropospheric GWs and the stratospheric dynamics influencing the GW source (pages 15-16)
Author Response
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Author Response File: 
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Reviewer 3 Report
There are some typos and grammar issues. Overall, the authors have addressed major concerns.
Line 23: propagating column ‘of’ GWs ‘above’ the Sichuan Basin
Line 124: results are “different” from the observations
Line 131: Please give references for “few studies”
Ines 154-156: I think you rewrite this sentence to just say “Following Hindley et al. [17], the upper limit of the data height of COSMIC -2 is limited to 50 km”
Line 198: interpolating à interpolated?
Lines 202-206: Should “changing trend” and “dispersion degree” just be variability or similar. I think “trend” is used for long-term changes and I don’t understand “dispersion degree”.
Lines 229 and below: Adding +/- standard deviation to the values will make the values more robust
Line 276: accompanied à accompanying
Line 335: “which” à ‘with’ or ‘and has’ completely different characteristics…..
Line 472: point à pointed
Line 517: Please check and correct for typos and grammar
Line 563: accompanied à correlated?
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors adequately revised the manuscript following the reviewer's comments. Thus I recommend publication of this manuscript in current form.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
Figure 5 JJA for the upper stratosphere illustrates a significant EP flux at 40 N in summer, relative to the other seasons. I think this might be pointed out in the discussion even though the reason may not be understood.
Figures 8 and 9 provide detailed information for the winter (DJF), but given the summer enhancement shown in Figure 5 at upper mid latitudes, I'm very curious why the summer wasn't included. These interests are relevant to the intra-annual variation in the mesosphere from below.
Reviewer 2 Report
Review of “Seasonal variation of stratospheric gravity waves in the Asian monsoon region derived from COSMIC-2 data” by Qu et al., submitted to Remote Sensing.
The paper by Qu et al., used COSMIC-2 temperature profile to study stratospheric gravity wave variations over the Asian monsoon region. The topic is relevant to the journal and there are some interesting findings on the source and propagation mechanisms of GWs at mid-latitudes. However, I have some major concerns. First, there appears to be a mistake in the formula used to calculate the potential energy (Ep). Secondly, the word “significant” is used throughout the text without being quantitative with error bars (or is it significant with 90%, 95% confidence etc.). I would also like point out the recent paper by Forbes et al. (2021) that provides some explanation about the GW propagation from monsoon regions, and maybe relevant to this study. More detail is provided in specific major comment below.
Major comments:
1) Abstract and text: The word “significant” is used a number of times. Please clarify how significant (i.e., 95% confidence etc.) or provide numerical values with errors when comparing different values.
2) The mean temperature () in the denominator of Equation (1) should be the background temperature (TB). I am not sure if this is a typo or a mistake. If it is not a typo, all the calculations will have to be redone, and this may or may not change your results. See for example, Strelnikova et al., (2021) and Tsuda et al., (2000) for correct formula. Note that while Tsuda et al. (2000) use they mention that this is the background temperature in section 3 of their paper.
Strelnikova, I., Almowafy, M., Baumgarten, G., Baumgarten, K., Ern, M., Gerding, M., and Lübken, F. (2021). Seasonal Cycle of Gravity Wave Potential Energy Densities from Lidar and Satellite Observations at 54° and 69°N. Journal of the Atmospheric Sciences 78, 4, 1359-1386, available from: < https://doi.org/10.1175/JAS-D-20-0247.1
Tsuda, T.; Nishida, M.; Rocken, C.; Ware, R.H. A global morphology of gravity wave activity in the stratosphere revealed 598 by the GPS occultation data (GPS/MET). Journal of Geophysical Research. 2000, 105, 7257-7273. DOI: 599 10.1029/1999JD901005
3) Figure 2: Please add error bars (at least the standard error of the mean). This will help to see if the differences between seasons is significant.
Moreover, in the discussion of Figures 3, 4, and 5, there are several qualitative words such as “relatively stronger, weak, small”, “second highest value of Ep”, “significant Ep” etc., and vague statements without any quantitative values. I recommend adding to the Figure 3 discussions with actual values (+- error bars) to be more quantitative.
4) Sections 3.1, 3.2, and the use of the meridional gradient of the westerlies as an “attractor”:
Forbes et al., (2021) analyzed the southern hemisphere monsoon regions as sources of GWs at 50 km and reported that the 15° southward shift in GW peak at 50 km compared to the monsoon region may be interpreted “in terms of wave focusing toward the middle atmosphere summer easterly jet core.”. The results presented in this manuscript is somewhat similar (in agreement?) with the Forbes et al., results. The authors might consider discussing their results in terms of the results from Forbes et al. (2021)
Forbes, J. M., Zhang, X., Randall, C. E., France, J., Harvey, V. L., Carstens, J., & Bailey, S. M. (2021). Troposphere-mesosphere coupling by convectively forced gravity waves during Southern Hemisphere monsoon season as viewed by AIM/CIPS. Journal of Geophysical Research: Space Physics, 126, e2021JA029734. https://doi.org/10.1029/2021JA029734
Minor comments:
1) Please define ‘dry’ in dry temperature profile
2) Please specify if the potential energy (Ep) calculated is potential energy density per unit mass or volume – I think you are calculating ‘per unit’ mass. Please specify in abstract and text. See Strelnikova et al. (2021) for definitions.
3) Line 70 says “COSMIC RO data with high spatial and temporal resolution” but in line 94 the text is “owing to the low data density of COSMIC RO,” – aren’t this contradictory statements? Please clarify.
4) Line 122: Please state the “inevitable errors” or provide reference.
5) Line 147: What is the height limit? 50 km or higher, please specify.
6) Line 190: Please explain “IDW (Inverse Distance Weight) interpolation” or provide reference
7) Line 193: How does “vertical gradient of Ep varies with height” compare to previous studies?
8) Line 312: Please specify value of ‘rate of decline’
9) Figure 9. Is the top right color bar for Ep? If so please specify measurement with units in both color bars. In Figures 9a, c, d, the x-axis also needs title(s) and units.
10) Line 509: But the GW information comes from Ep, no? So why is the “GW first extracted and the Ep calculated”. Should this be something like “The GW information was extracted from calculated Ep”?
11) Line 512: “on” à “in”?
Reviewer 3 Report
Please see the attached PDF file.
Comments for author File: Comments.pdf
