Historical Trends in Air Temperature, Precipitation, and Runoff of a Plateau Inland River Watershed in North China
Round 1
Reviewer 1 Report
In the reviewed paper, the historical trends in air temperature, precipitation, and runoff are studied for the specific area in northern China. In the current version, from my viewpoint, the paper cannot be published because the study looks like incomplete, and the paper looks scientifically poor. Thus, I suggest reconsidering the paper in order to improve its quality.
In the study of meteorological, hydrological and climatological time series, we must not only perform their statistical analysis, but we must perform a physical and statistical analysis. This means , first, that our understanding of the processes occurring in the environment (earth's climate system) should be based on a physical analysis of the processes in question, and mathematical models that describes these processes. Statistical analysis plays a secondary, albeit important, role. Performing statistical analysis, we thereby test some of our hypotheses obtained from physical analysis of the problem. Therefore, I suggest to perform a deep physical analysis of climatological processes in the area of interest and surrounding areas. In relation to statistical analysis, it is required to perform the spectral analysis, the analysis of variability and estimates of the accuracy of the obtained results. If all of these will not be done, then I do not recommend the article for publication
The next question is why should we perform this analysis? Authors wrote that "… for developing adaptive measures to climate change …". It would be great to know what kind of adaptive measures can be suitable for this geographical area.
Please, take in consideration that a lot of papers were published with respect to the influence of climate change on the global hydrological cycle (including precipitation and runoff) and the hydrological cycle at different parts of the globe including China. This issue should be discussed in the paper.
Author Response
We greatly appreciate the invaluable comments on our manuscript entitled “Historical Trends in Air Temperature, Precipitation, and Runoff of a Plateau Inland River Watershed in North China” (water-639996-Revision Reminder). We have carefully reviewed these comments and fully incorporated them into this revised manuscript.
To facilitate your further review, the following summarizes the reviewer comments (in italicized font) along with our responses (in boldface font). Also, revisions in the manuscript are highlighted using Track Changes.
In the reviewed paper, the historical trends in air temperature, precipitation, and runoff are studied for the specific area in northern China. In the current version, from my viewpoint, the paper cannot be published because the study looks like incomplete, and the paper looks scientifically poor. Thus, I suggest reconsidering the paper in order to improve its quality
ANSWER: The scientific relevance of this paper has been addressed. The authors have revised the paper to improve its quality
In the study of meteorological, hydrological and climatological time series, we must not only perform their statistical analysis, but we must perform a physical and statistical analysis. This means, first, that our understanding of the processes occurring in the environment (earth's climate system) should be based on a physical analysis of the processes in question, and mathematical models that describes these processes. Statistical analysis plays a secondary, albeit important, role. Performing statistical analysis, we thereby test some of our hypotheses obtained from physical analysis of the problem. Therefore, I suggest to perform a deep physical analysis of climatological processes in the area of interest and surrounding areas. In relation to statistical analysis, it is required to perform the spectral analysis, the analysis of variability and estimates of the accuracy of the obtained results. If all of these will not be done, then I do not recommend the article for publication
ANSWER: First, we highly appreciate the positive comments on the achievement of our manuscript.
Second, because of the lack of physical reasoning for climate changes, this work focused mainly on exposing the varying patterns of temperature, precipitation, and runoff in the Balagaer River watershed on the Mongolian Plateau in northeast China. This work is similar to others papers on regional climate change, including Bocheva et al. (2009) for Bulgaria; Gao et al. (2017), Zhang et al. (2019), and Wang et al. (2018) for the Chinese Mongolian Plateau region; Huang et al. (2017) for the Chinese Yellow River basin; Liang et al. (2018) for North China; Wang et al. (2016) for Chinese Horqin Sandy Land; Piao et al. (2010), Liang et al. (2011), Xu et al. (2011), Zhang et al. (2011, 2012), and Wang et al.(2013) for China; Karpouzos et al. (2010) for Greece; Sonali et al. (2013), Subash et al. (2011), Pingale et al. (2014), Pal and Al-Tabbaa (2009), and Minaei et al. (2018) for India; Ventura et al. (2002) and Cannarozzo et al. (2006) for Italy; Tabari et al. (2011) and Some'e et al. (2012) for Iran; de Lima et al. (2010) for Portugal; Gocic and Trajkovic (2013) for Serbia; del Rio et al. (2005) for Spain; T¨urke¸s (1996) and Partal and Kahya (2006) for Turkey; and Lettenmaier et al. (1994), Martinez et al. (2012), Rougé et al. (2013), Sagarika et al. (2014), Sayemuzzaman and Jha (2014), and Sayemuzzaman et al. (2014) for the United States).
Third, we added content to compare our findings with the temperature, precipitation, and runoff changes in northern China. The results showed that Imean was consistent with northern China’s increasing trend (Gao et al. 2017, Wang et al. 2015, Liang et al. 2018). We found the following: (1) The abrupt change in temperature preceded that in either runoff or precipitation and that abrupt changes occurred between 1970 and 2004. (2) Significant decreasing trends were found in the precipitation (-1.27 mm a-1) and runoff (-0.069 mm a-1) in the summer. Marginally increasing trends were found in the precipitation in the spring (0.18 mm a-1) and fall (0.032 mm a-1), whereas an insignificant decreasing trend was found in the runoffs in these two seasons. (3) Both precipitation and runoff in the wet season exhibited a significant decreasing trend, whereas in the dry season, they exhibited a marginally increasing trend. (4) Sudden changes in spring runoff and a sudden rise in temperature are the main causes of sudden changes in basin rainfall.
The next question is why should we perform this analysis? Authors wrote that "… for developing adaptive measures to climate change …". It would be great to know what kind of adaptive measures can be suitable for this geographical area.
ANSWER: According to Gao, precipitation and runoff as well as human activities jointly cause deterioration of eco-environmental issues, hydrologic process changes, water resource shortages, and grassland desertification in the cold and dry areas of steppe inland river basins. In recent years, the ability to detect historical trends in the hydrologic and meteorological elements is becoming increasingly imperative to provide a scientific basis for ecological environment management and agricultural production climate change. A large number of studies have shown the impact of climate change on precipitation and river runoff (e.g., Gao et al, 2017.)
what kind of adaptive measures can be suitable for this geographical area.
ANSWER: If watershed temperatures continue to increase or precipitation and runoff continue to decrease, watersheds will experience droughts. Higher temperatures and lower precipitation will lead to plant failure, frequent sandstorms, and grassland degradation, which will have a significant impact on agriculture and animal husbandry (e.g., cattle and sheep will have no forage, crops cannot grow, etc.). Because of the scarcity of surface-water and groundwater resources in the research area, climate change has had a significant impact on this area. If we can predict the trends in this area, we can work to prevent some climate disasters.
Please, take in consideration that a lot of papers were published with respect to the influence of climate change on the global hydrological cycle (including precipitation and runoff) and the hydrological cycle at different parts of the globe including China. This issue should be discussed in the paper
ANSWER: Previous research has been discussed. We considered that a lot of papers have been published with respect to the influence of climate change on the global hydrological cycle (including precipitation and runoff) and that the hydrological cycle varies in different parts of the globe, including China. We added this discussion to the paper.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The paper entitles "Historical Trends in Air Temperature, Precipitation, and Runoff of a Plateau Inland River Watershed in North China" is a useful attempt to use innovative approach but the presentation of work in its present shape has a number of shortcomings. The objectives and limitations are not clearly listed. The past literature includes a short list, however a strong case in the body of the paper is missing where a reader can conclude what are the gaps in the existing knowledge. I found lack of information and messages are mixed, needs a streamlined and better structured approach. Following are the major concerns:
The Introduction does not explain the rationale and what is lacking that justifies this review to be taken? The specific objectives of the study are lacking and there is no connectivity of the material in the existing form. The Introduction section needs further improvements. What are the weaknesses of the methods described in the previous literature and how these methods don't yield sufficient information for the current study? Literature review is insufficient with inadequate information. They need to be concisely reviewed and re-written in the comprehensive form. The specific objectives of the study need to be included. The relationship between objective and conclusion is of great importance which need to be revised or rewrite. The technical content of the paper i.e. methodology needs to be explained in detail. The re-structuring of the paper is recommended in order to improve the presentation. References are not completely presented and are incorrectly referred and citied. The authors are advised to use recommended format
Comments for author File: 
Comments.pdf
Author Response
We greatly appreciate the invaluable comments on our manuscript entitled “Historical Trends in Air Temperature, Precipitation, and Runoff of a Plateau Inland River Watershed in North China” (water-639996-Revision Reminder). We have carefully reviewed these comments and fully incorporated them into this revised manuscript.
To facilitate your further review, the following summarizes the reviewer comments (in italicized font) along with our responses (in boldface font). Also, revisions in the manuscript are highlighted using Track Changes.
The paper entitles "Historical Trends in Air Temperature, Precipitation, and Runoff of a Plateau Inland River Watershed in North China" is a useful attempt to use innovative approach but the presentation of work in its present shape has a number of shortcomings. The objectives and limitations are not clearly listed. The past literature includes a short list, however a strong case in the body of the paper is missing where a reader can conclude what are the gaps in the existing knowledge. I found lack of information and messages are mixed, needs a streamlined and better structured approach. Following are the major concerns:
1, The Introduction does not explain the rationale and what is lacking that justifies this review to be taken?
ANSWER: The rationale has been explained. Gao et al. [20], for example, believe that precipitation and runoff as well as human activities jointly cause deterioration of eco-environmental issues, hydrologic process changes, water resource shortages, and grassland desertification in the cold and dry areas of steppe inland river basins. In recent years, the ability to detect historical trends in the hydrologic and meteorological elements has become increasingly imperative to provide a scientific basis for ecological environment management and agricultural production climate change. A large number of studies have revealed the impact of climate change on precipitation and river runoff.
2, The specific objectives of the study are lacking and there is no connectivity of the material in the existing form. The Introduction section needs further improvements. What are the weaknesses of the methods described in the previous literature and how these methods don't yield sufficient information for the current study?
ANSWER: The objectives have been clarified. A large number of studies frequently have applied the nonparametric Mann-Kendall (MK) statistical test and Linear regression to detect trends in recorded hydrologic time series, including water quality, streamflow, and precipitation time series [20-23].
Most of the previous studies have focused on the temporal and spatial distribution changes of temperature, precipitation, and runoff, but have failed to discuss their mutual relationships or analyze their sensitivity to climate change and human activities. For example, Sonali et al. [24], Christopher et al. [25], and Omar et al. [26] focused mainly on temperature and precipitation trends without considering their possible responses to runoff, which likely biases the temperature-precipitation-runoff relationships. Liang et al. [27], Liu et al. [28], and Krishnakumar [29] conventionally examined trends of individual variables at annual or seasonal scales but only rarely scrutinized the interactions among the variables at monthly or daily scales. Minaei et al. [30] and Mao et al. [31] analyzed only historical temperature and precipitation changes and trends and did not discuss the change trend of river runoff and did not examine the relationship between river runoff and temperature and precipitation. Karl et al. [32] reported the impact of decadal fluctuations in mean precipitation and temperature on runoff; this was a sensitivity study covering the entire United States. This report, however, is relatively short in the time series analyzed and the research area was so large that the results are not applicable to the plateau inland river and grassland basin in cold and dry regions.
3, Literature review is insufficient with inadequate information. They need to be concisely reviewed and re-written in the comprehensive form. The specific objectives of the study need to be included. The relationship between objective and conclusion is of great importance which need to be revised or rewrite.
ANSWER: The literature review has been reviewed and revised.
4, The technical content of the paper i.e. methodology needs to be explained in detail. The re-structuring of the paper is recommended in order to improve the presentation.
ANSWER: The methodology has been explained and the paper has been restructured.
5, References are not completely presented and are incorrectly referred and citied. The authors are advised to use recommended format
ANSWER: The references have been completed and formatted as recommended.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
1. Please check English in lines 46-48.
2. I recommend to include in the text what adaptive measures can be suggested in this geographical area. You gave me the answer but did include something in the text.
Author Response
We greatly appreciate the invaluable comments on our manuscript entitled “Historical Trends in Air Temperature, Precipitation, and Runoff of a Plateau Inland River Watershed in North China” (water-639996-Revision Reminder). We have carefully reviewed these comments and fully incorporated them into this revised manuscript.
To facilitate your further review, the following summarizes the reviewer comments (in italicized font) along with our responses (in boldface font). Also, revisions in the manuscript are highlighted using Track Changes.
Please check English in lines 46-48.ANSWER: The lines 46-48 have been rephrased.
I recommend to include in the text what adaptive measures can be suggested in this geographical area. You gave me the answer but did include something in the text.ANSWER: The suggested measures were added in the lines 424-437（highlighted in green color）on page 15 of this revised manuscript.
Author Response File: Author Response.docx
Reviewer 2 Report
The author has addressed all the concerns raised. It may now accepted for publication.
Author Response
The author has addressed all the concerns raised. It may now accepted for publication.
ANSWER: Thank you very much!
Author Response File: Author Response.docx
