Review Reports

Round 1

Reviewer 1 Report

This article reviews the previous studies focused on the landfalling tropical cyclones in East Asia. The review is basically timely and useful for the future works on this subject and worth publishing in METEOROLOGY. However, I have some major concerns as listed below.

Major comments:

1.       This article includes some new results (Figs. 4 and 6) in addition to the review of the previous studies, and the previous studies are reviewed in the light of these new results. The differing conclusions from the various studies are likely due to the length of the data period, the seasons, the definition of the region and the datasets used (Lines 156-158). Therefore, the conclusions should be summarized in the light of the new results. However, some conclusions in the summaries are not consistent with the new results. It is difficult to see the “northward migration” (Lines 17, 228, 520, 529, etc.).  There are many differences within the southern regions (Vietnam, Philippines, S. China and Taiwan) and within the northern regions (Fujian, Zhejiang, Korea and Japan). Fig. 4 shows that LF TC frequency is increasing in Vietnam but decreasing in S. China. Fig.6 shows that APDI is increasing both in Vietnam and Korea. Furthermore, interdecadal variations in the southern regions and the northern regions are not necessarily opposite (Fig. 4 and 6).

2.       The phases of the interdecadal variations are different for different regions (Line 226). The relationship between the interdecadal variations of LF TC frequency or intensity for different regions and the atmospheric or oceanic interdecadal variations (IPO, PDO, PMM etc.) are not clear at all. How can the different phases of the interdecadal variations for the different regions be explained by the different atmospheric or oceanic interdecadal variations?

3.       The intensities of LF TCs are shown in terms of APDI in Fig. 6. However, APDI depends on both frequency and intensity. Similar figure for the intensity of LF TC should be shown, in addition to Fig.6. It is important to show the intensity variation to find the contributions of the frequency change and the intensity change to the APDI change.

Minor comments

1.       Line 17: I cannot see clear northward migration in the frequency of LF TCs in the last two decades (2000-2020) in Fig. 4.

2.       Line 135: “Fig.2” should be “Fig.2 of Liu and Chan (2008)”.

3.       Line 154: In this study, is Fujian included in “East China” and in “northern regions”?

4.       Line 162: Are “both Fujian and Taiwan” in the “northern regions”?

5.       Line 189: A period “.” is missing before “Cinco”.

6.       Line 228: “apparent northward shift” in the last 60-70 years (1950-2020) is not clear at all.

7.       Line 231: “more TCs have made landfall during the past decade” is not clear in Fig. 4.

8.       Lines 242, 245: Table 2 and Table 3 should be placed in section 6.1 where the tables are first referred to.

9.       Line 326: “Fig. 4f” should be “Fig. 6f”.

10.   Line 335: It may be too much to say “entire EA coast” as only Vietnam and Korea show significant increasing trend.

11.   Line 337: “shift in the location from south to north” is not shown clearly.

12.   Line 521-522: “more in the south and fewer in the north in the last half of the 20th century but opposite in the 21st century” is not consistent with the summary in section 3.1.7.

13.   Fig. 1: In Fig. 1c label of y-axis is missing. Labels (a) to (c) should be placed on the top left of each panel.

14.   Fig. 2: Labels (a) and (b) should be placed on the top left of each panel.

15.   Fig. 4 and 5: Labels (a) to (h) should be placed on the top left of each panel.

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

 

Reviewer 2 Report

This paper reviewed studies of time variation of landfalling tropical cyclones (TCs) in each region of the East Asian coast with an original data analysis. The present and future changes of landfalling TCs are discussed from many different viewpoints, and they are highly informative. The reviewer considers that the manuscript could be accepted for publication. However, there some comments and recommendations on the present manuscript. The reviewer kindly requests that the author would consider the following comments for revise. (In the following parts, "L" indicates the line number in the manuscript.)

1.         L44: This paper seems not to be a pure review but includes some author’s original data analyses as shown in Figs. 2, 4, and 6 as well as in Table 1. The reviewer suggests that this point should be indicated in the introduction. He also suggests that data section for the original analysis should appear before the section 2 Climatology.

2.         L71 and L587-589: Data used in the analyses of TC intensity are best track data from the China Meteorological Center and the Joint Typhoon Warning Center. These data include uncertainty in intensity. In particular, the uncertainty of TC intensity is significant since the aircraft observation was terminated in 1987. This uncertainty should be mentioned in the section of Introduction or the data section. Because the TC intensity change is a major topic of the present paper.

3.         L103: The change-point analysis may be based on Rodinov (2004). A brief description of the method should be indicated in somewhere of the paper.

4.         L107: This paper often mentions statistical significance. A brief description of the statistical test should be provided in somewhere of the paper.

5.         L134-135: Why is the northward shift of landfalling frequency consistent with the result in Fig.2? Figure 2 shows just the annual change of landfall.

6.         L212-213: A similar result is indicated by Yamaguchi and Maeda (2020), which should be cited over here.

Yamaguchi, M., and S. Maeda, 2020: Increase in the number of tropical cyclones approaching Tokyo since 1980. J. Meteor. Soc. Japan, 98, 775–786, doi:10.2151/jmsj.2020-039.

7.         L296-302: The extension of the time series by 1945 could be based on JTWC data. If so, a large bias seems to be present before ~1970 as in Figs. 6c, 6e, 6g and 6h. Emanuel (2005) mentioned that “Owing to changes in measuring and reporting practices since systematic observations of tropical cyclones began in the mid-1940s, there are systematic biases in reported tropical cyclone wind speeds that must be accounted for in analyzing trends”. He indicated a correction scheme in the Supplementary Methods for the JTWC best track wind speed before 1973. The reviewer just wonders if the correction was applied or not. If not, he recommends considering the correction.

Emanuel, K. A., 2005: Increasing destructiveness of tropical cyclones over the past 30 years. Nature, 436, 686-688. Online supplement.

8.         L314 and 319: The unit of wind speed should be unified: m/s or km/h.

9.         L509-510: With regard to intensity of landfalling TCs, there are few studies using high-resolution (1~4km) regional models. Tsuboki et al. (2015) found that future supertyphoons may make landfall over Japan as shown in their Fig. 5 and suggested that “These results suggest that midlatitude regions of East Asia, including Japan, are highly susceptible to the effects of supertyphoons in the future”. Using a high-resolution regional model, Kanada et al. (2020) indicated that even at mid-latitudes such as Japan, extremely strong typhoons, which are not observed in the present climate, can reach the region while maintaining axisymmetric structure in the RCP 8.5 future climate. These studies can be sited in the section of 5 Future Projections.

Tsuboki, K., M. K. Yoshioka, T. Shinoda, M. Kato, S. Kanada, and A. Kitoh (2015), Future increase of supertyphoon intensity associated with climate change, Geophys. Res. Lett., 42, 646–652, doi:10.1002/2014GL061793.

Kanada, S., K. Tsuboki, and I. Takayabu, 2020: Future changes of tropical cyclones in the midlatitudes in 4-km-mesh downscaling experiments from large-ensemble simulations, *Science Online Letters on the Atmosphere, 16, 57-63, doi:10.2151/sola.2020-010

 

Author Response

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Author Response File: Author Response.pdf

 

Reviewer 3 Report

This review is generally well-written, but I have some minor comments.

1, Line 28-29 the Interdecadal Pacific Oscillation and the Pacific Decadal Oscillation are usually regarded as the same mode for different target regions.

2. Keywords should include landfalling tropical cyclone.

3 Line 49, how the role of anthropogenic climate change in the current change in landfalling TCs should be discussed.

4. Line 107, could you give the literature for the argument “data are more reliable after 1975” and give more details?

5. I am very confused why the authors use the data from 1945, which are not reliable.

6. the quantity of the figures should be improved. 

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

 

Round 2

Reviewer 1 Report

The author revised the manuscript properly and now the manuscript is suitable for publishing in METEOROLOGY.