Interdecadal Change in the Relationship between the Winter Siberian High and Summer Tropical Cyclone Genesis Frequency over the Western North Pacific

Round 1

Reviewer 1 Report

A good piece of work.

reviewer added on 9 August:

1.What is the main question addressed by the research? Interdecadal change in the relationship between the winter Siberian high (SH) and tropical cyclone genesis frequency (TCGF)
2. Do you consider the topic original or relevant in the field? Does it
address a specific gap in the field? Yes
3. What does it add to the subject area compared with other published
material? Plausible dynamical mechanism attributing the change
4. What specific improvements should the authors consider regarding the
methodology? What further controls should be considered?

Authors have first constructed a couple of indices, viz.,  summer TCGF index,  SH index,  Niño3.4 index,  NPO index,  AL index and  The EAWM index. And then These indices have been computed in two different periods and simple correlation & regression analysis have been carried out. Observed significance in the difference has been attempted to explain dynamically, which appears to me convincing.
5. Are the conclusions consistent with the evidence and arguments
presented and do they address the main question posed? Yes

 

 

Author Response

We deeply appreciate this high appraisal from the reviewer, who gives us firm confidence to continue the exploration in this field. Even so, we still made some revisions to the manuscript through introspection in order to make this paper more rigorous and scientific.

Author Response File: Author Response.docx

Reviewer 2 Report

 

Gong et al analyse the mechanism of interdecadal change in the relationship between winter SH and summer TCGF. They argue that a changed SH-subtropical Pacific response acts to alter the impact on environmental background associated with WNP TCGF, which looks more like a appendage of SH affecting ENSO. This study is on a topic of much interest to the issue "Research on Tropical Cyclone: Formation and Implications" of Atmosphere. The results are interesting and the paper is worth of publishing. However, some improvements by addressing the following comments are needed before its publication.

major comments:

1).The physical mechanism description part is not detailed and complete, hope it can be supplemented

minor comments:

1) Lines 100-106: The authors should give the exact horizontal resolution of each data.

2) Line 155: Replace "response" with "relation". It has not yet been proved a "response" here. 

3)The the significance reference line of sliding correlation in Figure 1b should be added.

4) Vectors in Figure 6 displays blurry. The author may redraw it to present more clear. 

5) As a bridge, NPO affects the formation of subtropical circulation and TC, but in Figure 7a and 7c, the maximum correlation of SH-NPO shifts one month backward after linearly removing the influence of EAWM, how to explain this phenomenon.

 

Author Response

Response to Reviewer 2 Comments

Gong et al analyse the mechanism of interdecadal change in the relationship between winter SH and summer TCGF. They argue that a changed SH-subtropical Pacific response acts to alter the impact on environmental background associated with WNP TCGF, which looks more like a appendage of SH affecting ENSO. This study is on a topic of much interest to the issue "Research on Tropical Cyclone: Formation and Implications" of Atmosphere. The results are interesting and the paper is worth of publishing. However, some improvements by addressing the following comments are needed before its publication.

We appreciate the insightful suggestions and comments from this Referee. The reviewer affirmed the value of this study, pointed out the problems, and provided many useful suggestions for improving this manuscript. The following are our point-by-point replies.

major comments:

1).The physical mechanism description part is not detailed and complete, hope it can be supplemented

Thanks for this comment. Combined with the minor comments from the reviewer, the physical mechanism description part has been thoroughly revised, and we believe that the new version is clear and readable enough to be openly published.

minor comments:

1) Lines 100-106: The authors should give the exact horizontal resolution of each data.

Thanks for this comment. The horizontal resolution of ERA5 and GPCP data is 2.5º × 2.5º, and the horizontal resolution of the HadISST data is 1.0º × 1.0º. These detailed information has been added in the first paragraph of ‘Data and Methods’ section of the revised manuscript.

2) Line 155: Replace "response" with "relation". It has not yet been proved a "response" here.

Thanks for this suggestion. It has not yet been proved a "response" here, but the correlation is between SH in previous winter and tropical SST in later summer. We think this lead-lag "relation" may indicate a "possible response" of later summer to previous winter. The writing has been improved in the revised manuscript.

3)The the significance reference line of sliding correlation in Figure 1b should be added.

Thanks for this valuable suggestion. The significance reference line of sliding correlation has been added in Figure 1b of the revised manuscript.

4) Vectors in Figure 6 displays blurry. The author may redraw it to present more clear.

Thanks for this suggestion, which would make the plot information straightforward. We have redrawn Figure 6 to present it more clear in the revised manuscript.

5) As a bridge, NPO affects the formation of subtropical circulation and TC, but in Figure 7a and 7c, the maximum correlation of SH-NPO shifts one month backward after linearly removing the influence of EAWM, how to explain this phenomenon.

Thanks for this useful comment. As demonstrated, EAWM is much weaker during P1 than during P2, which can induce relatively stronger easterly wind anomalies over the tropical western Pacific in winter. As this stronger easterly wind anomalies over the tropical western Pacific is consistent with the southern flank of the subtropical anticyclone of negative NPO, we suppose it is conductive to induce more direct contribution to the formation of negative NPO. When the influence of EAWM is removed, the North Pacific is the only passway of the SH remote influence on NPO, which needs time to complete the “SH-AL-NPO” evolution. The maximum NPO response from winter SH will be later than that after removing the influence of EAWM. However, this hypothesis and its detailed mechanism are also worth to be further investigated. We have added following discussion in the revised manuscript.

“Moreover, it is noteworthy that the maximum correlation of SH-NPO shifts one month backward after linearly removing the influence of EAWM during P1 (Figure 7a and 7c). As demonstrated in Figure 6, during P1, EAWM can induce relatively stronger easterly wind anomaly over the tropical western Pacific in winter. This easterly wind anomaly is consistent with the southern flank of the subtropical anticyclonic circulation of negative NPO, which is supposed conductive to induce direct contribution to the formation of negative NPO. When the influence of EAWM is removed, the North Pacific becomes the only passway indirectly connect SH to NPO, which needs more time to complete the SH-AL-NPO evolution. This hypothesis may be a reasonable explanation of why the maximum NPO response in Figure 7c is one month later that in Figure 7a, but the detailed mechanism behind is still worth to be further investigated.”

Author Response File: Author Response.docx

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.