The Gulf Stream Front Amplifies Large-Scale SST Feedback to the Atmosphere in North Atlantic Winter
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsReview comments on “The Gulf Stream front amplifies the large-scale SST feedback to the atmosphere in winter North Atlantic”
The authors investigated impact of the gulf stream front on large-scale SST feedback to the atmosphere in the winter North Atlantic using global community atmosphere model. It is demonstrated that the large-scale SST anomaly in the central North Atlantic provides feedback to atmosphere and excites a wave train extending through Eurasia and the wave train in the North Atlantic is strengthened by approximately 40%, and the wave activity flux toward downstream is highly intensified. The large-scale SST is combined with strong Gulf Stream (GS) front, highly increased water vapor is released from the GS region, resulting in a 50% increase in moisture transport towards the western Europe. The precipitation and diabatic heating are highly increased on the western Scandinavian Peninsula. The authors did an excellent analysis and the paper can be accepted for publishing after some modifications:
Major comments
1) In Figure 1, the regression pattern of SST can be generated through atmosphere forcing and how can we justify that the atmospheric pattern is caused by the SST pattern? A lag regression (SST leads atmosphere) is expected?
2) In Figure 1a), the fourth REOF modes only explain 5.85% variance, does this mean that the impact of gulf stream front is below 5.85% to the total variance? How much is the contribution of gulf stream front to the total variance?
3) In Figure 2, the pattern of HGT at 300hpa moves westward in FLTR, what causes that? How about the changes in surface flux (e.g. sensible heat flux, latent heat flux, ……)?
4) In Figure 4, the relationship between SST and storm track can be caused by the third forcing (e.g., changes in the Pacific). How to justify that the changes in storm track is caused by the SST?
5) In Figure 5a), the pattern moves downward, what causes that?
6) The authors only did the analysis for winter season (DJF). How about other seasons?
Minor comments
1) The horizontal resolution 0.25o may not be called “high resolution” . Currently, the operational global model is 13km for US Global forecast system (GFS) and 9km for ECMWF
Comments on the Quality of English LanguageMinor changes are needed.
Author Response
Please find the detailed response in the following file.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsMy commenst for Authors:
1. introduction, please add more papers for literature review.
2. discussion, please compare your solution/results with research from literature review
3. references, add more paper, see point 1.
Author Response
Please find the detailed response in the following file.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsIn this study, two sets of ensemble experiments are conducted using a high-resolution global Community Atmosphere Model forced by SST in boral winter from 2000 to 2013. The regional averaged SST and its variation in the experiments are identical, and the only difference is the strength of the SST front in GS region. This paper shows very interesting results in connection with the Gulf Ocean front. In order to be published in the journal, slight modifications are required as pointed out as follows, especially the way of writing of the results, discussion and conclusions.
1. P.4, Figure 1: The result of REOF4 and REOF3 have been shown in this diagram. What are the results from the first and the second component from REOF analysis? Also what are the physical interpretations for these undescribed principal components? These predominant components might contain important physical processes.
2. P.3 Eqs. (1) and (2): The horizontal velocity is defined twice immediately after each equation. Are these duplicate definitions? Or different quantities?
3. P.3 “3. Results”: The description in his section is too lengthy and unclear. Thus, the reviewer strongly suggests the authors to separate the “3. Results” into a few or several sub-sections, such as “3.1 ***”, “3.2 ***”, and “3.3 ***”
4. P.10 “4. Conclusions and discussion”: The reviewer strongly suggests the authors to put the “discussion” in “3. Results and Discussion” to be more clearly separated in term of contents. In particular, Figure 9 seems to be most important results in this study, which must be put in “3. Results and Discussion”, rather than in “4. Conclusion.”
5. P.12 Figure 9(a): SST gradient: As it seems to be dimensional, write the unit in the paper. If it is normalized, its definition must be clearly described in the paper.
Author Response
Please find the detailed response in the following file.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors' replies solve my concerns; in my point of view, the paper can be accepted for publishing.
Comments on the Quality of English LanguageLooks good to me.
