Temperature Variations and Possible Forcing Mechanisms over the Past 300 Years Recorded at Lake Chaonaqiu in the Western Loess Plateau

Round 1

Reviewer 1 Report

My review is in pdf file, and I just uploaded it

Comments for author File: Comments.pdf

Author Response

Thank you very much for the careful review and useful comments. We have fully considered the opinions from reviewer, and the revisions made in light of your suggestions are attached.

Author Response File: Author Response.docx

Reviewer 2 Report

This manuscript presents reconstructed temperature variations at the juncture of the East Asian Monsoon region and the arid northwestern China. The potential implications of such studies are important, since more high-resolution long-term temperature reconstructions can help understand climate variabilities and explore related mechanisms. And the reconstructions can also serve as forcing/boundary condition in paleo-climate modeling or compare to model output. I am impressed by the amount of the work the authors did, including not only sampling and reconstructing, but also comparing with literatures and climate data. The manuscript is clearly structured but relatively poorly written with some confusions and ambiguities. Another major concern is with some misinterpretations of the results. Overall, I think the manuscript could be published with revisions that will improve the overall clarity/flow of the story and make the story more convincing.

 

Here are my major concerns for the contents:

 

1. As a person in the field of Atmospheric Science, I am not convinced that the carbonate content reflects temperature by the last paragraph in section 4.1 and Figure 6. Firstly, I did not see any citations validating the relationship in the paragraph. Are there any previous work proving the relationship is solid? Secondly, it was stated in the first paragraph in section 4.1 that the proxy has been used to indicate E/P. Then the authors further validated the relationship by comparing the proxy to the temperature from meteorological stations (lines 199-204). But I do not see E/P in the figure, and E/P could correlate well with temperature. Thirdly, from the comparison of the proxy with the meteorological station data in Figure 6, I do see the increasing trend in both. However, if we detrend this long-term increase and focus on the decadal changes (11-year running average), the trends to be the opposite for most of the time. This difference should be justified to convince the audience that the relationship is solid. Otherwise, this could be a misinterpretation.

 

2. I am not clear on how the cold/warm periods are detected based on the carbonate content data. For example, it seems to me that the carbonate content is similar in the warm period of 1783-1818 and in the cold period of 1930-1946. So, what is the criteria used for picking up these periods? E.g., average values, trends, or comparing to neighbor values.

 

3. I do not think the significance of this study is clearly shown especially in the first several sections of the manuscript. I was not very clear on the purpose of conducting this research and the gaps it could fill after reading the introduction. After the entire manuscript, I realized the importance of the work and that the introduction did not serve it function well.

 

To me, the introduction should state the current development of the field, the gaps/discrepancies that hinders the development of the field, and how the current work could potentially fill the gap. From the first paragraph, I know that the significance is to present this long-term high temporal resolution dataset. But how sparse can previous datasets be? Is there a critical resolution that could significantly improve our understanding/analysis? From the second paragraph, it seems that the gaps are “there are notable discrepancies in both the timing and magnitude of reconstructed events that remain unresolved” (Lines 55-56), but there is no further clarification on what these discrepancies are, with no specific descriptions or citations. Then I do not see these discrepancies are further discussed in the rest part of the paper, only similarities.

 

 

 

 

And other minor concerns not mentioned above:

 

1. I would like to see some quantitative analysis rather than qualitative ones.

 

• Lines 199-204, what about conducting statistical analysis to see how significant the proxy is related to temperature?

 

• Lines 238-239. “a considerable degree of convergence among the various datasets”. How considerable could it be? Give a correlation coefficient and p value?

 

• Lines 313-315 “the warm PDO phase coincides with elevated temperatures and reduced precipitation in northern China”. Again, what about showing a correlation coefficient and p value to demonstrate the relationship of PDO with precipitation.

 

2. The writing the paper needs improving, some need clarification, some are too general and should be more specific, and some are redundant to me.

 

• Manuscript wide suggestion: think of a topic sentence for each paragraph and try to demonstrate the idea at the first sentence of each paragraph. I will give some examples of the poorly written/organized parts.

 

• Lines 49-51. Include some citations of previous studies in this region. And make it a little specific, what the most related paleoclimatic changes are.

 

• Lines 206-211, an example of poorly written/organized sentences. It has been concluded that the results reveal all the six cold periods, right? As written in these lines, I have to finish reading all three sentence to understand the idea. When just finishing the first sentence, I was confused on why there are only four cold periods.

 

• Lines 257-276. I think it redundant to just copy and paste these sentences, since you already have them with line numbers in Table 1, and just citing the line numbers could be enough. Same goes with other citations to the table.

 

• Lines 286，290，299 “solar activity” is too general and vague to me. Be more specific if you mean solar irradiance.

 

• Section 4.4 is poorly structured and organized. I agree with the idea that PDO, rather than solar irradiance, could be the major cause. And I was expecting a brief review of all possible factors with citations (at the very beginning), and how previous showed that which ones might not be the dominant factors, and which ones might have a bigger impact, and finally how the current study support the idea.

 

• Figure 6: I do not see in the figure caption what the green and yellow shadings stand for, and why the last green shading does not reach the bottom axis.

Comments for author File: Comments.pdf

Author Response

Thank you very much for the careful review and useful comments. We have fully considered the opinions from reviewer, and the revisions made in light of your suggestions are attached.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I think the paper can be accepted now