To understand the influence of the westerly wind and EASM on precipitation in the Alxa Plateau, Xiao et al. used dendrochronology to examine the tree-rings from its three sites. It is well known that the study region is influenced by the interaction of EASM and westerly, and there have been quite a few studies on this topic using different approaches. However, in this article, the authors didn’t not identify shortcomings of previous studies and point out the scientific problems.  They also didn’t explained why their approach is better suited to address these issues. In summary, the motivation behind this study is unclear.

The article exhibit poor overall writing quality, making it challenging to read. The authors excessively use abbreviations, some of which are unnecessary. Many sentences require rephrasing, and there are organization problems. Several sections, especially Introduction, need reorganizing or rephrasing.  After introducing the background, the literature review doesn’t need to include all the previous studies. The purpose of the review is to summarize the major findings or our current understanding of the topic with this article, highlighting the problems with existing studies, and present scientific questions that this article aims to address.  

The Abstract needs rewriting. A good abstract should include the following components: the general background with scientific questions, details about investigation methods, major findings, and hypothesis for what you observed. The implications or significance can be included at the end, although it is optional.

To establish a correlation between two data sets, the authors intentionally divided them into different groups and conducted correlation analysis (Figures 6 and 7). However, the methodology for this correlation analysis is questionable and lacks scientific basis. For any pair of data sets, it's possible to selectively choose a small portion of data and find a so-called correlation between them.

Several figures were presented in the text without detailed explanations or descriptions, and some captions lack informativeness. In the results section, the first part is extremely challenging for any reader to follow, and this section should be merged with the next, focusing on introducing general observed patterns rather than detailed or exact years with variations.

While reviewing the article, I made some comments (see attached annotated PDF file). Hope that they can assist the authors in improving their article during the revision.

This manuscript attempts to interpret the interaction between the westerlies and monsoons in the arid regions of northwest China from the perspective of historical climate using tree-ring data from three locations. While it has some regional representativeness, upon reviewing the entire manuscript and comparing it with previous work, significant deficiencies are identified. Firstly, the theme and content of the manuscript lack cohesion, failing to pose scientific questions for resolution. The discussion section is unclear, lacking coherence and substance. Secondly, the chosen theme has seen considerable innovative research, yet the manuscript fails to distinguish itself from similar studies or highlight intriguing aspects. Lastly, the entire document requires thorough language editing and improvement. Paragraph distribution should be compact and logical, unnecessary content should be removed, and detailed explanations should enhance content relevance.

Specific editing suggestions:

1) Line 24: "Qinghai spruce?" Use the Latin name for plant species, the same applies to line 284, etc.

2) Lines 45 and 51: Citation error, reference 2019a should precede 2019b.

3) Line 48: What does EASM stand for? Same for subsequent instances.

4) Lines 49 to 52: Grammar errors, merge long and short sentences into one.

5) Line 55: Unclear subject reference.

6) Line 72: Extra space.

7) Lines 77 to 80: Does "which" refer to your team or dendrochronology? Clarify.

8) Subsection 1.2: Summarize previous research concisely, highlighting key points rather than listing references.

9) Lines 122 to 123: Currently, there is no clear theoretical support for the impact of reconstruction results on desertification control.

10) Line 129: Unclear referent for "it." Merge sentences for clarity.

11) Line 130: Add reference.

12) Subsection 2.1: Streamline, remove irrelevant content.

13) Line 186: What standard method? Provide reference.

14) Line 190: Specify the method for constructing the chronology or provide a reference.

15) Lines 200 to 203: Reference for SPEI data source and justification for choosing SPEI over PDSI needed.

16) Line 230: What is SD? Specify the full name if it is standard deviation.

17) Lines 238 to 241: Why use RES chronology?

18) Table 1: Statistical indicators should be based on synthetic chronology results.

19) Subsection 3.2: Why no discussion of seasonal correlation? Which season does the radial growth signal indicate?

20) Table 2: Consider using a graphical representation for better clarity; tables appear disorganized.

21) Figure 5: Inconsistent color transparency in gray bands.

22) Line 479: Clarify the intended message.

23) Lines 511 to 534: Unclear discussion; is there a close connection to the manuscript's theme?

24) Line 540: Extra space.

25) Lines 553 to 554: No significant correlation between DS and EASM; how can monsoon decline be interpreted as promoting tree growth?

Xiao et al present tree ring width records from three different parts of the Alxa Plateau covering climate history of this region for about two centuries. The region was claimed to be affected by both the westerlies and the East Asian Summer Monsoon. To understand the history of the interactions between the westerlies and the EASM, the authors attempts to use the presented tree ring records from the Alxa Plateau to reconstruct the history of such interactions. Although understanding the interaction is the main focus, however it is still unclear to me how did the westerlies and the EASM interact with each other in this region after reading through the manuscript. Many scientific terms and expressions in the manuscript lack a concise definition to improve readability. Further, the authors need to improve the presentation of manuscript not only for language but also the organization of the paper.

Major comments:

When the authors indicate the interaction between the westerlies and the EASM, it is not clear what is the precise meaning of the interaction. Did the authors mean the shift of the boundaries, the influence between each other, or something else? The authors should make this point clear to let readers correctly understanding the scientific content delivered by the authors.

The authors should briefly introduce the definition and calculation procedure of any index that has been used in manuscript. For instance, there are many different definitions of the EASM index. Only give a citation to the index that has been used is not friendly to readers not familiar with these indexes.

When calculating correlation coefficients, the authors may need to make it clear how the degrees of freedom were adjusted to account for serial correlation in the data, and that this procedure applies to all correlation coefficients and significance levels.

Other comments:

L284-286: is it a quantitative representation of a specific index of the wet/dry conditions or just a qualitative representation?

L284-286: as low precipitation is the major limiting factor, is it possible that the records are more sensitive to drought while less sensitive to wetter conditions?

Figs 6 and 7: from the figure captions, these two figures look identical. The authors may need to revise the figure caption to make the difference between the two figures clearer.

There are some typos and grammar errors in the manuscript. The authors need do a through check on the writing of the paper.