Extreme historical droughts and floods in the Hanjiang River Basin, China, since 1426

Zhang, Xiaodan; Ren, Guoyu; Yang, Yuda; Bing, He; Hao, Zhixin; Zhang, Panfeng

doi:https://doi.org/10.5194/cp-18-1775-2022

Articles | Volume 18, issue 8

https://doi.org/10.5194/cp-18-1775-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/cp-18-1775-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 18, issue 8

Research article

|

03 Aug 2022

Research article |

| 03 Aug 2022

Extreme historical droughts and floods in the Hanjiang River Basin, China, since 1426

Xiaodan Zhang, Guoyu Ren, Yuda Yang, He Bing, Zhixin Hao, and Panfeng Zhang

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Final revised paper (published on 03 Aug 2022)
Supplement to the final revised paper
Preprint (discussion started on 05 May 2021)
Supplement to the preprint

Interactive discussion

Status: closed

CC1:
'Comment on cp-2021-43', Shichao Xu, 13 Jun 2021

The object and content of this manuscript are relevant and necessary in the context of global warming and the frequency of extreme disasters. The Hanjiang River is a key control basin for China's South-North Water Transfer Central Project water source area and flood control in the middle reaches of the Yangtze River. Its changes in precipitation, droughts and floods will have a wide range of socio-economic impacts, and there is an urgent need for research on long time scales of precipitation and drought and flood variability. Nice work. I think the manuscript is well-written and researched; the topic of study and the methods employed are appropriate for Climate of the Past.

Still, I have some small minor suggestion:

-Line 235: “A total of 4328 records of droughts and floods in the HRB from 1426-1950 were collected from the above-mentioned historical documents.” I think it is important to describe exactly which datasets these available drought and flood records come from , so that the reader has a clearer idea of the composition of the sources.

-The few references in English cited in the text are not conducive to scholars from countries other than China to consult the relevant papers, and the number of references in English should be increased.

Citation: https://doi.org/10.5194/cp-2021-43-CC1
- AC1: 'Reply on CC1', Xiaodan Zhang, 13 Jun 2021
  
  Dear Xu,
  Thank you very much for your interest in our work and for your very constructive comments and suggestions, which are indeed very valuable to improve our work. We will seriously consider your sincere suggestions.
  Thank you!
  Best wishes,
  
  Xiaodan Zhang
  
  Citation: https://doi.org/10.5194/cp-2021-43-AC1
CC2:
'Comment on cp-2021-43', Junpei Hirano, 29 Jun 2021

Authors highlighted multi-decadal to century-scale variations of

drought and flood events in Hanjiang River basin based on historical documents
I think this manuscript is well organized and topic of this work is important

for understanding long-term variations of extreme events in historical period.
This manuscript is worth publishing for Climate of the Past.
As a suggestion, I have some following comments
Figure 1: Author claims that investigating long-term variations in extereme events

within medium to small scale river basin is important due to comprehensive influences,

such as topography and geomophology(P3, line 110-114). Therefore, I think it is better to

show topography of Hanjiang River Basin in this Figure 1. Readers outside of China

are not familir with topography in this area.

Figure 5: Author analyzed correlation between El Nino and extreme floods in Hanjiang River Basin. As authors analyzed long-term(multi-decadal to century-scale) variations, I think it is better to give somme comments on relationship with PDO. Changes in the PDO phase occur on multidecadal, rather than inter-annual timescales. If appropriate proxy for PDO is available, correlation analysis with PDO and could provide more robust results on multi-decadal to century-scale variations on extreme floods.

Figure6: Author showed that large volcanic eruptions may influence occurrence of the extreme floods in Hanjiang River Basin.

I think it is better to explain some possible mechanism for relationship between volcanic eruptions and

occurrence of extreme floods in this area.

Citation: https://doi.org/10.5194/cp-2021-43-CC2
- AC2: 'Reply on CC2', Xiaodan Zhang, 01 Jul 2021
  
  Dear Prof. Hirano,
  Thank you very much for your interest and comments on our manuscript. You have provided a series of very significant directions for improving this manuscript, and we will carefully consider your sincere suggestions for guidance.
  Kind regards,
  
  Xiaodan Zhang
  
  Citation: https://doi.org/10.5194/cp-2021-43-AC2
- AC5: 'Reply on CC2', Xiaodan Zhang, 21 Aug 2021
  
  Dear Prof. Hirano,
  
  Thank you for your valuable comment. In the revised version, we will add topographic information to Figure 1 and label the corresponding names included in each representative site. All place names covered in this manuscript will be labeled.
  
  Because of the limited space in this article, the relationship with PDO is expected to be discussed in the future. After considering other experts' comments on section 3.2(ENSO and volcanic eruptions), we decided to move this section to the discussion section and replace section 3.2 with an analysis of the spatial distribution of extreme droughts and floods in the Han River basin. We will also add some words in the discussion section to analyze the relationship between extreme droughts/floods in the Hanjiang River basin and decadal to multi-decadal variability of East Asian summer monsoon.
  
  Thank you again!
  
  Kind regards,
  
  Xiaodan Zhang
  
  Citation: https://doi.org/10.5194/cp-2021-43-AC5
RC1:
'Comment on cp-2021-43', Anonymous Referee #1, 18 Jul 2021

The comment was uploaded in the form of a supplement: https://cp.copernicus.org/preprints/cp-2021-43/cp-2021-43-RC1-supplement.pdf

Citation: https://doi.org/10.5194/cp-2021-43-RC1
- AC3: 'Reply on RC1', Xiaodan Zhang, 21 Aug 2021
  
  Dear reviewer1,
  Our response is uploaded as an attachment. Please find the attachment file.
  Yours sincerely,
  
  Xiaodan Zhang
  
  Citation: https://doi.org/10.5194/cp-2021-43-AC3
RC2:
'Comment on cp-2021-43', Anonymous Referee #2, 09 Aug 2021

The comment was uploaded in the form of a supplement: https://cp.copernicus.org/preprints/cp-2021-43/cp-2021-43-RC2-supplement.pdf

Citation: https://doi.org/10.5194/cp-2021-43-RC2
- AC4: 'Reply on RC2', Xiaodan Zhang, 21 Aug 2021
  
  Dear reviewer2,
  Our response is uploaded as an attachment. Please find the attachment file.
  Yours sincerely,
  
  Xiaodan Zhang
  
  Citation: https://doi.org/10.5194/cp-2021-43-AC4

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (08 Sep 2021) by Chantal Camenisch

AR by Xiaodan Zhang on behalf of the Authors (09 Oct 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (28 Oct 2021) by Chantal Camenisch

RR by Anonymous Referee #1 (21 Nov 2021)

RR by Anonymous Referee #2 (09 Jan 2022)

RR by Anonymous Referee #3 (13 Jan 2022)

Suggestions for revision or reasons for rejection

<Overall comments>
The reviewer was invited as a third reviewer of this paper, and this will be the first review. The authors present long-term flood/drought variations in the Hanjiang River Basin (HRB) in central Chia from 1426 to 2017 based on historical documents and meteorological and hydrological data in recent years. The results will be valuable for understanding long-term climate change history in that region. Although the target region is not very large, this kind of regional climate change study will be valuable. According to the responses to the former reviews, the authors seemed to make major revisions in this version. However, still remained a number of ambiguous points as listed below, and the paper needs major revisions.

<Major comments>
1. They showed Figure 3 to show the validity of their flood/drought index and observed precipitation. They concluded they were well correlated and their flood/drought index was reasonable. However, when the curves are compared with the years in Table 2, the listed extreme flood and drought years seem not to match with the minimum or maximum of the curves in Fig. 3. Will they plot these extreme years in Fig. 3 to check the validity of these data and explain the reason of the differences if they differ in some years?
2. They divided the whole period into three stages. But in the latter description it seems nothing was considered on interpreting the results. It will be needed how they treated such data discrepancies during the target period.
3. Their terminology in describing place/region names is very vague as pointed out below, and sometimes not consistent in the paper which greatly prevents the content from easy understanding.
4. Sometimes, their results seem to contradict with or are different from the former studies results, but they simply regarded these portions to be “consistent with the former studies”. They need to carefully compare their results with the former studies and explain the reason for the discrepancies.
5. Although they seem to add English references, adding two more important former studies on long-term Asian monsoon variability from the 15th century by Shi et al. (2018, 2019) will be recommended.

<Specific comments>
1. L26-28: It is rather hard to understand the relationship between the lower flood/drought frequencies in the upper reach, and the highest sensitivities to droughts and floods in the Ankang region located in the upper reach.
2. L44-45 and many others: The reviewer is not familiar with this journal’s citation policy, but normally, the cited references are arranged from old to new, or alphabetical order.
3. L65: The word “especially” may not be needed, since this situation is not limited to eastern China’s monsoon region.
4. L112-113: Need to add the averaged periods for the average annual precipitation and runoff.
5. L116-117: It is not sure if these topographic features are the main reason for the severe droughts and floods.
6. L119: In Fig. 1 “Jianghan Basin” is labeled, not “Jianghan Plain”
7. L139: “century AD” -> “century BC” (?), since “for more than 3000 years”.
8. L141: Many people will not be familiar with the period of “Qing Dynasty”. It will be better to specify the target period of this dataset.
9. L157: It seems all these stations are in the HRB. Which stations are “around HRB”?
10. L185-186: It was not clearly understandable the terms “representative area”, “site”, and “most counties’ situation”.
11. L188-191: The method how to make this ideal frequency needs to be explained.
12. L208: This definition of the term “site” needs to be explained earlier (See comment 10). Better to show county and municipalities boundaries in Fig. 1 or explain such region names’ conditions. Also add how they are called in Chinese.
13. L230: Is there any meaning of the value “20%”?
14. L236: How do you calculate the precipitation anomaly percentages? Is it just 8 station mean value? Are the interannual variabilities within only several percent? Then it will be highly stable precipitation regime.
15. L285: In the 1580s and 1730s no extreme droughts are listed in Table 2. Also, no extreme droughts are in 1628-1641. Are they indicate the inconsistent results with this paper?
16. L294: When and where the “Ming Chongzhen drought” occurred?
17. L297: When is the Danjiangkow Reservoir constructed? For which purposes?
18. L298-299: Which region’s average precipitation are these values indicated?
19. L301: 1660s -> 1610s.
20. L306: Are any flow rate data available before 1959? It is not sure if the 20 times are abundant or not from this description only.
21. L311: Need to show the recorded period to indicate the “record high”.
22. L312: Is “lake Taibai” located in Fig. 1? If yes, please label it, or if no, please indicate how much it is located downstream of the eastern limit of Fig. 1.
23. L315: The years 1631-1632 and 1979-1980 are not listed in Table 2.
24. L323: Where is Wudu County located, and same comment as No. 22. Same as for the Baiheliang stone fish in L326.
25. L353-355, Table 3: According to the definition of extreme flood/drought years in L250-255, they are not the same as Grade 1 or 5 years. It is very confusing that they used extreme flood/drought years to be similar as Grade 1 or 5 years.
26. L 367-368: From Figure 5, both floods and droughts are higher in the lowland not in the upper reaches. Isn’t it a different result from the former studies?
27. L369-373: In L118, Zhongxiang is regarded as a starting point of the downstream, but here it is regarded as the middle reach which make the readers to be confused. In addition, Qianjiang and Wuhan in the lowland have higher drought frequency than in the upper catchment. Need more careful description.
28. L373: From the figure 5 -> From Figure 5
29. L382: It is not clearly understandable why they regarded higher flood/drought grades in Fig. 6 to be “sensitive”.
30. L402-404: Why upper HRB droughts are more correlated with droughts in North China, while middle and lower HRB floods have stronger relationship with the middle and lower Yangtze River Basin? Any climatological evidence in recent years?
31. L461-468: The comparisons with East and South Asianδ18O show not strong relationship with flood/drought frequencies in the HRB. Need to change their discussion on this point.
32. L501: Any explanation on the reason why the HRB is more prone to floods when the South Asian monsoon is stronger?
33. References: He does not know this journal’s policy but the reference order may need to be arranged alphabetical order. In addition, use consistent style for small/capital letter usages in the titles of the paper and/or the journal names.
34. Fig. 1: As for (b), it is hard to distinguish green filled circles indicating study site from the background pale green color in the lowland areas. Better to change the color of the study area to be more easily distinguishable color. Put label of “Qinling Mountains” to be located somewhat southward, since they will be the northern boundary of the HRB. In addition, add unit for the color bar.
35. Fig. 4: The method of making this figure is questionable. 1. In the graph, the earliest year is labeled as 1426, but the caption shows it is from 1430. 2. It is not very sure how the precise year is located. For example, in Table 2, 1433 is listed as one extreme drought year in the 1430s. Maybe it is plotted as the second decade one extreme drought in Fig. 4a. No extreme flood year is listed during the 1420s or 1430s in Table 2. However, in the first decade starting from 1426, one extreme drought and flood is listed in Fig. 4c. The situation in the 1990s are also not clear. How do you define 10-year period? Is it starting from the year xxx0 oy xxx1? 3. Why you did not include the 21st century record? If you use the whole period data, it should be from 1426 to 2017, shouldn’t it?
36. Fig. 5: The color bar for drought condition map will be better to be changed to indicate reddish color to be higher frequency, like their drought grade maps, since bluish color may feel wetter conditions.
37. Fig. 9: The top right figure label will be “drought years”, not “flood years”.
38. Table 2: The top line of the 20th Century Extreme drought years: 194 -> 1941

<References>
Shi, H., B. Wang, E. R. Cook, J. Liu, and F. Liu 2018. Asian summer precipitation over the past 544 years reconstructed by merging tree rings and historical documentary records. J. Climate, 31, 7845−7861, doi:10.1175/JCLI-D-18-0003.1
Shi, H., B. Wang, J. Liu, and F. Liu 2019. Decadal-multidecadal variations of Asian summer rainfall from the Little Ice Age to the present. J. Climate, 32, 7663−7674, doi:10.1175/ JCLI-D-18-0743.1

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ED: Reconsider after major revisions (02 Feb 2022) by Chantal Camenisch

AR by Xiaodan Zhang on behalf of the Authors (28 Feb 2022) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (04 Mar 2022) by Chantal Camenisch

RR by Anonymous Referee #3 (24 Mar 2022)

Suggestions for revision or reasons for rejection

<Overall comments>
The authors made substantial revisions based on the previous reviewers’ comments, and now the quality of the paper has been much improved. Most of the responses to the reviewers seem to be satisfactory. However, still remained a number of issues as listed below, and the paper needs major/minor revisions.

<Major comments>
1. Their figure captions are still not satisfactory. Need more improvement as listed in below specific comments.
2. The biggest remaining issues will be in their discussion. They need to carefully making discussion considering the time-scale. In addition, there may be no consensus on the similarity of the variability between the East and South Asian monsoon in recent period. How do they regard the monsoon situation when both flood and drought situations are pronounced, for example, in recent decades? Furthermore, the El Niño and La Niña events may also be related with East Asian monsoon in the interannual time-scale, therefore they may not be independent factors.

<Specific comments>
1. L1¬–2, 36: It will be better to add “, China”, or “, central China” after “basin” in the title, and delete “China” from the key words, since “Hanjing River basin” may not be familiar for most overseas readers
2. L24 and many others: Better to use en-dash “–” instead of hyphen for the year or page or value ranges. Also, in the figures and references.
3. L26–28: The meaning of this sentence is not understandable.
4. L45–48: Better to refer the latest AR6 results.
5. L55: Northeastern -> Northeast
6. L59: “the precipitation in North” -> “that in North”
7. L131: Specify the measurement location of the runoff amount.
8. L141–143: In Fig. 3, it is shown that after the 200 no drought occurred, while two floods happened. This statement will not be good.
9. Fig. 1: Better to omit minute/second values from the latitude/longitude labels, and enlarge a bit their font size.
10. Fig. 1: The insert in (a) need to be labeled as, for example, “(a)”, since some of the legends for “Huanjing River Basin” and “Yangtze Mainstream” are only for that inserted figure. Need to specify such legends. The present version of the legends in (a) may cause confusions.
11. Fig. 1: What is a green symbol in (b)?
12. Fig. 1: The elevation color bar units are wrong.
13. L165: “historical” -> “Historical”
14. L181–182: Need to add reference for this precipitation dataset.
15. L196: Is “Vientiane Cave” correct?
16. L196–197: Need to show the location, and brief explanation on how past East or South Asian monsoon activities were reconstructed.
17. L196: Two “Zhang et al. (2008)” exist in the reference list. Need to specify which.
18. Table 1: Second column: Is the left inequality sigh correct?
19. Table 1: Third, fourth, and fifth columns: Use minus sign, not hyphen.
20. L284–286: This method may cause confusions. Precipitation is for “May–September" or “Annual” precipitation? In addition, What is “average precipitation”?
21. L314: Add published year of Xie et al.
22. L341: “dashed”->“dotted”?
23. L357–286: Need to add references for these records.
24. L487, L512: 1953 -> 1935
25. Table 5: Better to divide this table into two tables for the situations in droughts in North China and floods in the Yangtze River.
26. Fig. 9: What are the darker or lighter grey parts indicated? What are curves in (b) and (c)?
27. Figs. 9, 10, L591 etc.: The target period is not exactly the multiple number of 30-year. How do they treat the fraction years?
28. L565: Need to add the region of flood or drought conditions.
29. L567: In case “summer monsoon” is used, which monsoon index is referred to “East Asian” or “South Asian” or both?
30. L567–569: In a centennial year time-scale, it can be regarded as “monsoon was generally weak” and extreme drought events were relatively more likely, but in a decadal time-scale, for example, in late 16th century, extreme floods are common but no droughts were recorded. How they consider such decadal scale conditions?
31. L570–575: Very rare floods in the 18th century may not be well explained by these monsoon indexes, since even in the similar monsoon index levels, for example, in the 15th century by the East Asian monsoon index, or the early 20th century by the South Asian monsoon index are observed, though a number of extreme floods occur.
32. L584–589: A vague correlation analysis. What did they use an index for the drought and floods grades in a 30-year time window?
33. Fig. 10, left panel: Better to add number labels on the horizontal axis to be, like “1525, 1615, 1705…” with 90 intervals to match with the 30-year period divisions.
34. Fig. 10 right column: Omit “-1” from the horizontal axis label, instead add numerals from zero to 8 or 10.
35. L609–611: Confusing statements. Which monsoon East or South Asian influence more on the HRB precipitation and how?
36. L633–634: The meaning of this sentence is not understandable.
37. References: Need to reorder alphabetically.

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RR by Anonymous Referee #2 (12 Apr 2022)

ED: Reconsider after major revisions (21 Apr 2022) by Chantal Camenisch

AR by Xiaodan Zhang on behalf of the Authors (13 May 2022) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (15 May 2022) by Chantal Camenisch

RR by Anonymous Referee #3 (26 Jun 2022)

ED: Publish subject to minor revisions (review by editor) (27 Jun 2022) by Chantal Camenisch

AR by Xiaodan Zhang on behalf of the Authors (30 Jun 2022) Author's response Author's tracked changes Manuscript

ED: Publish subject to technical corrections (05 Jul 2022) by Chantal Camenisch

AR by Xiaodan Zhang on behalf of the Authors (07 Jul 2022) Author's response Manuscript

Short summary

Applying yearly drought and flood records from historical documents and precipitation data in the period of instrumental measurements, this study constructs a time series of extreme droughts and floods in the Hanjiang River Basin from 1426–2017 and analyzes the temporal and spatial characteristics of the extreme drought and flood event variations.