Skill and Intercomparison of Global Climate Models in Simulating Wind Speed, and Future Changes in Wind Speed over South Asian Domain

Round 1

Reviewer 1 Report

The author should check the following sections:

1. There are too many conclusions. Please ensure the abstract contains all important conclusions.
2. It is known model 29-31 are the ensembles of GCMs. Could the authors explain how model 29-31 are integrated.
3. The linear lines of figure 1-8 are too thick for viewing, please consider thinning the linear lines.
4. In section 2.2, how to correct the output deviation of the climate model? It is known that bilinear interpolation is required. Could you please explain further?
5. Figure11 - 14 are not clear enough.
6. Please make sure there are no grammatical and spell errors in the text.
7. The innovation and originality of the article needs to be further explained.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Authors present an extensive manuscript on intercomparison of GCMs over South Asian domain in present and future climate conditions using statistical parameters. The overall impression is that authors, wishing to show everything they analyzed, have lost the focus and the main points of the paper are not comprehensible. Consequently, the manuscript is very hard to follow. The manuscript needs to be rewritten and major changes should be introduced. The English writing and style should also be carefully edited.

Here are some general points:

1. I strongly recommend to split this manuscript in two papers which will, afterwards, have a clear take home messages. This will also reduce the number of figures, which I also find excessive. In other words, I am of impression that all the presented figures disclose the same point. Authors should show only the figures which disclose their main points (3-5 points would be enough). Furthermore, all the climate change part should be in a separate manuscript which will then also be more focused and precise.

2. All presented GCMs have a very coarse resolution. Authors state that there are studies which did not show improvements with complex processes included in the CMIP6 phase. This is not surprising since GCMs have limited number of processes which could be included. The majority of them still has to be parametrized due to the very low resolution. In the recent decade the resolution of climate models has significantly increased, to ~ 12 km for regional climate models, or even ~ 1 km in convection-permitting models. Therefore, I am wondering, why did authors use coarse resolution GCMs when there are also RCMs available over the domain of interest (https://cordex.org/domains/region-6-south-asia-2/)? In my opinion, the necessity of using GCMs for evaluation and projections of the wind speed is questionable, especially on the daily scale. (Sub)Daily wind field is a highly variable parameter largely affected by fine spatio-temporal scale aspects. 
   Taking everything into account, are GCM wind field climate projections reliable over the south Asian domain?

3. The statistical scores for the evaluation part are nicely presented and suitable. However, the climate change methodology is lacking. I was wondering whether authors use weighted climate change means since it is in the first part of the paper revealed which simulation performs best and which is inferior in skill over their domain?

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Dear Author,

Please consider the comments below: 

1. Line 17, if you use a term in bracket, it should refer to the word before it. “Low” does not represent “high”. If you mean both high and low situation, you can use “high or low”. Please revise it.
2. The same situation “best(worst)”, “strengthening (weakening)” .
3. In the abstract, there should be important quantitative results. Please add.
4. Line 116, what do you mean by “accurate wind”? Wind speed? Wind direction? Or sth else? Please revise.
5. In Table 1, “Atmospheric Resolution” should be “Spatial Resolution”.
6. The spatial resolution of the models greatly varies as seen from Table 1. How did you manage this differences? Did you manage any image or data registration or compared them as their natural resolutions? Please not only respond me, but also add explanations to the text.
7. Line 168, the reference data set has a spatial resolution of 0.25° x 0.25°. If you compared this reference data and model ID 3 (spatial resolution of 2.7906° x 2.8125°), the results are not reliable. In such cases, we generally resample the reference data to the lower resolution that we will compare and than registration process is applied to overlap the pixels. Please let me know about your application. If the application was carried out directly without registration or reverse of my explanation (model data is resampled to reference data), you should clarify this drawback in the discussion.
8. The results and the analyses are well-prepared.

All the best.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

I highly appreciate the changes authors did to improve the manuscript. However, I would still recommend to make some major changes before publication.

General comments:

1. I , again, highly recommend to edit or proofread the manuscript by a native English speaker.
For example l.155-l.162 would read better in this way: "This study evaluates the ability of available GCMs of the CMIP5 project to simulate the near-surface wind speed (WS) over the South Asian domain (11°S to 30°N and 26°E to 107°E, Figure 1). The overall confidence in GCMs' future projections depends on their skill in representing the historical climate [36]. In order to understand how the CMIP5 GCMs represent historical and present wind climate, we used a common historical period ranging from 1979 to 2005, and a near-present time period ranging from 2006 to 2019. Mentioned periods are selected based on the GCM and ERA5 wind field data availability.", etc...

2. I do now better understand the three main points authors want to share, and I respect the authors' choice not to split the manuscript in two parts. Consequently, there should be FOUR main points addressed in the Introduction. The 4^th may refer to: 4) Disclose the regions where the changes in future wind speed are significant in order to make mitigation strategies. Taking this into consideration, the background of climate projections of the wind field and the relevant literature is missing. I recommend starting this paragraph from line 136.
In addition, the manuscript would benefit of adding a paragraph about the present-day monsoon climatology (obtained from e.g. observational stations, satellites, NWP models,...), for those readers who are not familiar with this typical wind regime over your region. Some parts of the Results section could, than, be moved to the Introduction (i.e. l.459-l.461, l.531, etc)

3. Conclusion section is still confusing. Please rewrite it in a more focused way with clear take-home messages.

1^st paragraph is repeating the methods, which is fine.
2^nd paragraph is a mix of evaluation and projection results

3^rd paragraph should come earlier. Also, RCMs are mentioned here for the first time. “...Thus, the added value of using finer resolution Regional Climate Models (RCMs) over GCMs in representing wind speed is questionable and will be addressed separately...” You don’t know that, since you do not examine RCMs in this particular study. Thus, this is not the conclusion you derive from your results and does not belong to your conclusions.

4^th paragraph is again about projections.

Other remarks:
l.84-l.90 I recommend deleting this part (or rearranging it). It does not support your choice of using CMIP5 models.

l.90-l.97 Consider moving this part in the last paragraph of the Introduction.

Table 1. All the numbers and symbols should be written in a uniform manner.

l.132-l.134 Are those climate projections or climate model evaluation in the period 1979-2005?

l.994 I think authors name is missing here. "by Mohan et al. [21]"

Figures 11-14. This are the ensemble means, right? Please write it in the figure caption.

Section 3.4. - Are all future changes statistically significant? Did you make the tests similar to what you have already done in the evaluation part?

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Dear Authors,

Thank you for your responses. Actually, I already know the spatial resolution management. I have already accepted the paper; however, the explanations in your "Response 7" should be given in the paper for the readers.

All the best.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

Dear authors,

I appreciate all the changes made through all the stages of this review process. Now I feel the manuscript can be accepted for publication.

Best regards!