Drought Characteristics and Causes during Winter Wheat Growth Stages in North China
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDrought Characteristics and Causes During Winter Wheat Growth Stages in North China
[ID: 3048514]
General Comments: It is an interesting research work on winter wheat. It is an important crop of China regarding their food production. So the topic is very much related to food security, economical as well as social stability. The introductory part should be more precise and suggest incorporating a paragraph about the crop (Taxonomy, Ambient conditions for cultivation etc.). Methods mainly follow the meteorological data, climatic conditions and statistical analysis, it should be better for incorporation some field data in present days from the mentioned study areas. I suggest minor revisions before acceptance.
Line No Remarks
16 Mention full form of abbreviation first time
28 Arrange alphabetically
158 Check it
258, 263, 292, 297, 300 Use [ ]
306,
328, 331, 334, 337 Put under the bracket [ ], and mention below the table
398 Put under the bracket [ ]
520 Mention Author name
Comments for author File: 
Comments.pdf
Author Response
Point 1: The introductory part should be more precise and suggest incorporating a paragraph about the crop (Taxonomy, Ambient conditions for cultivation etc.).
Response 1: Thanks for the constructive comments made by the referee. According to your constructive suggestions, in the revised manuscript, we have added a paragraph about the crop in the introduction to provide readers with a better understanding of the research background and significance.
Point 2: Methods mainly follow the meteorological data, climatic conditions and statistical analysis, it should be better for incorporation some field data in present days from the mentioned study areas.
Response 2: Thanks for the constructive comments made by the referee. This study primarily analyzes the spatial and temporal evolution of drought and its causes during different growth stages of winter wheat in North China from the perspective of meteorological drought, without considering remote sensing data, agricultural activity data, and hydrological data. Therefore, future research will further collect data on soil, vegetation, hydrology, and socio-economic factors. By incorporating more field data and other data sources, and combining existing research methods and analytical techniques, we will be able to more accurately assess the impact of climate change on the environment, thus providing stronger support for future research and practice.
Point 3: Line 16: 'Mention full form of abbreviation first time'.
Response 3: Thanks for the constructive comments made by the referee. According to your suggestions, we have revised “SPEI-1” to “Standardized Precipitation-Evapotranspiration Index at 1-month timescale (SPEI-1)” in line 16 in the revised manuscript.
Point 4: Line 28: 'Arrange alphabetically'.
Response 4: Thanks for the constructive comments made by the referee. According to your suggestions, we have revised the keywords alphabetically in line 28 in the revised manuscript.
Point 5: Line 158: 'Check it'.
Response 5: Thanks for the constructive comments made by the referee. According to your suggestions, we have checked it and revised “R” to “R (R Core Team, Vienna, Austria)” in line 158 in the revised manuscript.
Point 6: Line 258, 263, 292, 297, 300, 306: 'Use [ ]'.
Response 6: Thanks for the constructive comments made by the referee. According to your suggestions, we have revised “( )” to “[ ]” in line 258,263,292,297,300 and 306 in the revised manuscript.
Point 7: Line 328, 331, 334, 337: 'Put under the bracket [ ], and mention below the table'.
Response 7: Thanks for the constructive comments made by the referee. According to your suggestions, we have put the sentences under the bracket and mentioned below the table in line 328, 331, 334 and 337 in the revised manuscript.
Point 8: Line 398: 'Put under the bracket [ ]'.
Response 8: Thanks for the constructive comments made by the referee. According to your suggestions, we have put the sentences under the bracket in line 398 in the revised manuscript.
Point 9: Line 520: ' Mention Author name '.
Response 9: Thanks for the constructive comments made by the referee. The author of “Summary of the China Flood and Drought Disaster Prevention Bulletin 2020” is “China Flood and Drought Disaster Prevention Bulletin Editorial Committee”.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsExploring the characteristics of drought disasters is among the most critical issues in current research fields of hydrology, meteorology, agriculture, and environmental science. In the present work, taking North China as the study region, the authors comprehensively reveal the patterns of droughts occurring during wheat growing seasons by using the popular SPEI along with a series of statistical method. Generally speaking, I think this is a well-written and content-rich paper, and their reached conclusions can provide rich guidance for reducing crop drought disasters and optimizing field water management in North China under climate change.
On the other hand, I also have some concerns regarding the explicitness and preciseness of this paper, which should be addressed before publication:
-Although the SPEI is commonly used to quantify drought conditions in this field, it should be also noted that, the SPEI value is not equal to “drought intensity”. To be specific, only when SPEI <-0.5 or <-1.0 (see Line 167), the parts of SPEI values can be used in some way to represent drought intensity. However, in your paper, SPEI-1 values were directly employed in trend analysis. It may easily confuse or mislead readers. For instance, ‘a significant increase in SPEI’ refers to a significant increase in wetness (because the SPEI value is positive) but not dryness. So, in your paper, “significant upward trends of SPEI”, means drought or flood? Anyway, you should clarify this point well in this paper.
-Many similar drought indices were employed (lines 168-176) here, but I am wondering whether it is necessary. As clearly seen in Abstract and Conclusion, I cannot find important findings showing the efficiency of employing so many indices. Instead, I think a few critical drought indices may be more informative. Or if you chose to display them all, please emphasis on their different results.
-Different growth stages of wheat are considered in this paper, and you compared the drought indices among different stages. This work is meaningful because the impacts of drought on crops depends on growth stages. However, I am wondering if the length of different stages can affect your results. As you stated in lines 152-154, the three stages had different lengths. So, the drought events at the longer stages should be more than those at the shorter stages. Did you think about excluding the effects of different lengths of different stages? Such as dividing the number of months.
-In the Introduction, Lines 60-67, which discusses the calculation methods of ET, should be moved to M&M. You know, this is only a detail of calculation process.
-The authors used too many long sentences, but many of them are wrong in grammar or hard to be understood. Thus, please carefully examine all your long sentences in this article, and if possible, please replace them with clarified short sentences.
-At the end of Discussion, I strongly suggest the authors to add the limitation of your work. For instance, the rough division of wheat growth stages many have impacts on your conclusions. As we know, regional scale investigations usually disregard many uncontrolled factors, or are restricted by limited data. So, please think about them.
Comments on the Quality of English Language
Minor editing of English language required
Author Response
Point 1: Although the SPEI is commonly used to quantify drought conditions in this field, it should be also noted that, the SPEI value is not equal to “drought intensity”. To be specific, only when SPEI <-0.5 or <-1.0 (see Line 167), the parts of SPEI values can be used in some way to represent drought intensity. However, in your paper, SPEI-1 values were directly employed in trend analysis. It may easily confuse or mislead readers. For instance, ‘a significant increase in SPEI’ refers to a significant increase in wetness (because the SPEI value is positive) but not dryness. So, in your paper, “significant upward trends of SPEI”, means drought or flood? Anyway, you should clarify this point well in this paper.
Response 1: Thanks for the constructive comments made by the referee. In this paper, we use the Standardized Precipitation Evapotranspiration Index (SPEI) to quantify the degree of climate wetness or dryness. However, it is important to recognize that the SPEI value itself does not directly equate to drought intensity. To more accurately describe the characteristics of drought events, we utilized run theory to identify and describe drought events on a monthly time scale, based on the method by Yao et al. [49]. Specifically, when the SPEI value is less than -1.0, we consider that month as the beginning of a drought event, which continues until the SPEI value rises above 0, marking the end of the drought event.
In the trend analysis, we used SPEI-1 values to assess the spatial trends of climate wetness or dryness across the study area. However, it must be emphasized that the trend analysis of SPEI-1 values does not directly reflect changes in the intensity or frequency of drought events but rather reveals the overall trend of climate wetness or dryness. To avoid confusion and misunderstanding among readers, we have specifically distinguished between significant wetness and significant dryness in the trend analysis.
Point 2: Many similar drought indices were employed (lines 168-176) here, but I am wondering whether it is necessary. As clearly seen in Abstract and Conclusion, I cannot find important findings showing the efficiency of employing so many indices. Instead, I think a few critical drought indices may be more informative. Or if you chose to display them all, please emphasis on their different results.
Response 2: Thanks for the constructive comments made by the referee. In this manuscript, we chose to employ multiple drought event characteristic indices in order to comprehensively and thoroughly evaluate the features of drought events from multiple dimensions and perspectives. These various drought indices reflect key aspects such as drought duration, intensity, peak value, and severity, jointly establishing a comprehensive framework for understanding drought events. We recognize that highlighting only some indices in the abstract and conclusion sections of the paper may cause confusion for readers. While writing the paper, we did strive to emphasize the most significant findings and conclusions within the limited space. However, this does not imply that we neglected the importance of other indices. To address this potential limitation, we have included discussions on the impacts of other drought indices in the conclusion section of the paper, aiming to emphasize their crucial roles in comprehensively understanding drought events.
Point 3: Different growth stages of wheat are considered in this paper, and you compared the drought indices among different stages. This work is meaningful because the impacts of drought on crops depends on growth stages. However, I am wondering if the length of different stages can affect your results. As you stated in lines 152-154, the three stages had different lengths. So, the drought events at the longer stages should be more than those at the shorter stages. Did you think about excluding the effects of different lengths of different stages? Such as dividing the number of months.
Response 3: Thanks for the constructive comments made by the referee. Indeed, in this manuscript, we used growth stage divisions based on previous research: the seedling stage from October to November, the overwintering to jointing stage from December to April, and the booting to maturity stage from May to June. These stages have different lengths, which may result in more drought events occurring in longer stages compared to shorter ones. In our analysis, we primarily focused on the impact of drought events on wheat during different growth stages and did not directly exclude the influence of the varying lengths of these stages. However, we recognize that this is an issue worth further exploration. To more accurately assess the impact of drought events on wheat growth, we plan to consider excluding the influence of different stage lengths in future research.
Point 4: In the Introduction, Lines 60-67, which discusses the calculation methods of ET, should be moved to M&M. You know, this is only a detail of calculation process.
Response 4: Thanks for the constructive comments made by the referee. According to your constructive suggestions, in the revised manuscript, we have moved the content from lines 60-67 in the introduction to the " Dataset and methods " section.
Point 5: The authors used too many long sentences, but many of them are wrong in grammar or hard to be understood. Thus, please carefully examine all your long sentences in this article, and if possible, please replace them with clarified short sentences.
Response 5: Thanks for the constructive comments made by the referee. According to your constructive suggestions, in the revised manuscript, we have carefully reviewed all long sentences in the text to ensure they are grammatically correct and easy to understand. We have also broken down complex long sentences into clearer short sentences to improve the readability of the article.
Point 6: At the end of Discussion, I strongly suggest the authors to add the limitation of your work. For instance, the rough division of wheat growth stages many have impacts on your conclusions. As we know, regional scale investigations usually disregard many uncontrolled factors, or are restricted by limited data. So, please think about them.
Response 6: Thanks for the constructive comments made by the referee. According to your constructive suggestions, In the "Discussion" section of the paper, we have added a discussion on the limitations of our research and clearly pointed out the implications of these limitations for future studies.
Author Response File: Author Response.docx
Reviewer 3 Report
Comments and Suggestions for AuthorsDear Editor,
I would like to thank you for your confidence in reviewing this manuscript.
I send you here my comments for the manuscript review.
Type of manuscript: Article
Title: Drought Characteristics and Causes During Winter Wheat Growth Stages in North China.
Remarks/suggestions
The work was properly designed and I recommend its publication after revisions.
Introduction:
The introduction needs to be shortened.
Dataset and methods
Line 117: Replace “400-800mm” by “400-800 mm”.
Figure 1b: Explain in the title the term “DEM”.
References:
Please check references (in text and list) in relation to the journal's recommendations.
Author Response
Point 1: The introduction needs to be shortened.
Response 1: Thanks for the constructive comments made by the referee. In the revised manuscript, We have revised the introduction, removed redundant content, making it more concise and clear.
Point 2: Line 117: Replace “400-800mm” by “400-800 mm”.
Response 2: Thanks for the constructive comments made by the referee. According to your suggestions, we have revised “400-800mm” to “400-800 mm” in line 117 in the revised manuscript.
Point 3: Figure 1b: Explain in the title the term “DEM”
Response 3: Thanks for the constructive comments made by the referee. According to your suggestions, We have explained the DEM after the title in Figure 1(b) in the revised manuscript.
Point 4: Please check references (in text and list) in relation to the journal's recommendations.
Response 4: Thanks for the constructive comments made by the referee. We will thoroughly review the in-text citations and reference list to ensure they comply with the journal's requirements. For any discrepancies, we have made the necessary modifications and adjustments to ensure that all citation formats are accurate and conform to the journal's guidelines. Thanks again.
Author Response File: Author Response.docx
