Observed Exposure of Population and Gross Domestic Product to Extreme Precipitation Events in the Poyang Lake Basin, China

Round 1

Reviewer 1 Report

Review of atmosphere-640794: Observed Exposure of Population and Gross Domestic Product to Extreme Precipitation Events in the Poyang Lake Basin, China by Zhan et al.

 

In this study, the authors investigated population and GDP exposure to extreme precipitation events (EPEs) in the Poyang Lake Basin in China. The EPEs were defined as intensity reached a certain threshold. Some of my main concerns are summarized in the following.

The precipitation threshold seemed to be arbitrary. A more meaningful definition would be intensity related to a clearly defined return period such as 50-year, 100-year or whatever frequency for the region based on historical data. I didn’t really see the purpose of the exercise of spatialize method of population. The end result of this exercise was to generate a spatial map in Figure 4, which looks like a density map. It is not clear why the authors needed to use a regression model to do that. Same comment also applies to the GDP map in Figure 5. Therefore, I saw these exercises were more a distraction to the main objective rather than significant scientific value. The authors claimed that the IAD approach as innovative, yet they cited three references in describing the steps. If it is innovative, it should be clearly stated that what is innovative compared to these references. This innovative point should be clearly outlined in the Abstract and Introduction.

Therefore, I recommend a major revision to clearly demonstrate the main contributions of this study, which seemed to be the population and GDP exposure to EPEs in large and major watershed in China. I feel the whole concept can be convincingly articulated in a much condensed manuscript similar to a Technical Note if this journal has this paper type.

Author Response

Dear Editor and Reviewers:

 

Thank you very much for your valuable comments. We have addressed the comments raised by the reviewers, and our amendments are identifiable by red text in the revised version of our article. Our point-by-point responses to the reviewers’ comments are presented on the following pages.

Once again, we would like to thank you for your time and consideration. Following the revision of our article, we hope that you will reconsider it for publication.

 

Best regards,

 

Dr. Zhan Mingjin on behalf of all co-authors

 

 

 

 

 

 

 

 

 

 

Reviewers’ comments and our responses:

Reviewer 1

Comments to the Author:

The precipitation threshold seemed to be arbitrary. A more meaningful definition would be intensity related to a clearly defined return period such as 50-year, 100-year or whatever frequency for the region based on historical data. I didn’t really see the purpose of the exercise of spatialize method of population. The end result of this exercise was to generate a spatial map in Figure 4, which looks like a density map. It is not clear why the authors needed to use a regression model to do that. Same comment also applies to the GDP map in Figure 5. Therefore, I saw these exercises were more a distraction to the main objective rather than significant scientific value. The authors claimed that the IAD approach as innovative, yet they cited three references in describing the steps. If it is innovative, it should be clearly stated that what is innovative compared to these references. This innovative point should be clearly outlined in the Abstract and Introduction.

Therefore, I recommend a major revision to clearly demonstrate the main contributions of this study, which seemed to be the population and GDP exposure to EPEs in large and major watershed in China. I feel the whole concept can be convincingly articulated in a much condensed manuscript similar to a Technical Note if this journal has this paper type.

[Question 1]

The precipitation threshold seemed to be arbitrary. A more meaningful definition would be intensity related to a clearly defined return period such as 50-year, 100-year or whatever frequency for the region based on historical data.

[Response] 

Thank you for your suggestion. When I started this research, I was also hesitant on how to choose the most suitable threshold value. Actually, I initially selected 50-year and 100-year as threshold values but it was found that the threshold values were too high. Figure 1 shows the precipitation of the Poyang Lake Basin. The annual precipitation is around 1661 mm (max 2128 mm in 1998; min 1114 mm in 1963). The maximum daily precipitation of each station in each year should exceed 100 mm. Even if I use 1-year precipitation, the value should above 100 mm; however, the disaster threshold value is in fact smaller than 100 mm.

Figure 1. Annual precipitation of Poyang Lake Basin

There is a second reason for my choice of 50 mm/day as the threshold. In China, 5 0mm/day is the standard for rainstorm level; if the precipitation is larger than 50 mm/day, the precipitation is then classified as a rainstorm. If the weather forecast includes precipitation of more than 50 mm/d, the government will issue a blue warning signal. There are four levels of early warning signals in China: blue, yellow, orange, and red (in order of increasing severity). For these reasons, I selected 50 mm/d as a threshold value.

[Question 2]

I didn’t really see the purpose of the exercise of spatialize method of population. The end result of this exercise was to generate a spatial map in Figure 4, which looks like a density map. It is not clear why the authors needed to use a regression model to do that. Same comment also applies to the GDP map in Figure 5. Therefore, I saw these exercises were more a distraction to the main objective rather than significant scientific value.

[Response] 

Thank you for your patient and careful review. In the IPCC SREX Report (2012), the risk depends not only on hazards, but also on exposure and vulnerability.

                        Risk = Hazard ´ Exposure ´ Vulnerability

The exposure refers to the amount of property and population exposed to the disaster. Therefore, if I want to calculate the exposure of the GDP and population, I must know the distribution the GDP and population. This is why I produced Figures 4 and 5.

 

 

 [Question 3]

The authors claimed that the IAD approach as innovative, yet they cited three references in describing the steps. If it is innovative, it should be clearly stated that what is innovative compared to these references. This innovative point should be clearly outlined in the Abstract and Introduction.

[Response] 

I apologize because I perhaps did not explain this clearly, which led to your misunderstanding. I did not mean to imply that I created the IAD method, I only quoted this method. I think the IAD method is innovative because it links together three important features of extreme events: intensity, impact area, and duration. In the past, we paid more attention to single station research and ignored the impact area.

Author Response File: Author Response.docx

Reviewer 2 Report

Detailed and thorough analysis of EPEs over time, and their economic impacts. Intensity and frequency have slowly increased, and and interacting with growing population and GDP means that the economic impact has increased much faster.

Much of the methodological detail presented is probably mainly of interest to a minority of specialists, so I would suggest splitting the paper: a first short section summarizing the results, and a second section or appendix containing all the details for reference.

Author Response

Dear Editor and Reviewers:

 

Thank you very much for your valuable comments. We have addressed the comments raised by the reviewers, and our amendments are identifiable by red text in the revised version of our article. Our point-by-point responses to the reviewers’ comments are presented on the following pages.

Once again, we would like to thank you for your time and consideration. Following the revision of our article, we hope that you will reconsider it for publication.

 

Best regards,

 

Dr. Zhan Mingjin on behalf of all co-authors

 

Reviewer 2

Detailed and thorough analysis of EPEs over time, and their economic impacts. Intensity and frequency have slowly increased, and interacting with growing population and GDP means that the economic impact has increased much faster.

Much of the methodological detail presented is probably mainly of interest to a minority of specialists, so I would suggest splitting the paper: a first short section summarizing the results, and a second section or appendix containing all the details for reference.

[Response] 

Thank you for your support. I think your opinion deserves full consideration but unfortunately, Atmosphere does not have articles in this format.

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors' revision seems to follow the reviewer's suggestions in a satisfactory manner. I have only one suggestion, as in my review, some editing of the English would be helpful. Thus GDP is described as ' inflation normalised' or non-normalised', whereas the standard terminology is real or nominal GDP.

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.