Simulation Performance and Case Study of Extreme Events in Northwest China Using the BCC-CSM2 Model
Round 1
Reviewer 1 Report
This manuscript is well organized and the drawn conclusions are coherent with the obtained results. The references should be updated to include more recent studies. This manuscript should be revised by an English Native Speaker. The authors write too long sentences.
Lines 9 – 14: This sentence is too long. Please, reduce this part of the manuscript.
Line 28: To arrange the key words alphabetically.
Lines 45 – 49: I think that you should add these recent references to support your sentence “Therefore, climate models are not only an effective tool for describing the study of the interaction of the five major circles of the climate system and their impact on climate change, but also an important tool for humans to be able to grasp the evolution of the climate system, study the characteristics and behavior of the current climate, and predict and anticipate future climate change”. I would like to suggest:
Ali, H., et al. (2021). Expanding or shrinking? range shifts in wild ungulates under climate change in Pamir-Karakoram mountains, Pakistan. PloS one, 16(12), e0260031.
Tang, X., et al. (2021). Maximum entropy modeling to predict the impact of climate change on pine wilt disease in China. Frontiers in Plant Science, 12, 652500.
Lines 112 – 125: Please, describe better your hypothesis and predictions.
Lines 179 – 181: Lines 45 – 49: I think that you should add these recent references to support your methods “Correlation analysis: correlation analysis is a method for analyzing the correlation between two variables, and is an important method often used in the analysis of the causes of weather and climate change processes [27]”. I would like to suggest:
Anand, V., et al. (2021). Predicting the current and future potential spatial distribution of endangered Rucervus eldii eldii (Sangai) using MaxEnt model. Environmental Monitoring and Assessment, 193(3), 1-17.
Lines 218 – 425: Please, add the scale and the north symbol in all the map figures in the results,
Lines 472 – 503: This section of the manuscript should be greatly expanded. Please, discuss your results comparing them also with other studies already published.
Author Response
Point 1: Lines 9- 14: This sentence is too long. Please, reduce this part of the manuscript.
Response 1: Thank you for your rigorous comment. We have modified the structure of this sentence.
The BCC-CSM2 model is the second generation of the Beijing Climate Center Climate System Model developed by the National Center of China Meteorological Administration. Using the outputs of two resolution versions of the BCC-CSM2 model: BCC-CSM2-MR and BCC-CSM2-HR, which are contributing to phase 6 of the Coupled Model Intercomparison Project (CMIP6), the simulation performance on the climate characteristics in Northwest China during 1961-2014 is compared.
Point 2: Line 28: To arrange the key words alphabetically.
Response 2: We are grateful for the suggestion. We have reworked the order of the keywords.
Point 3: Lines 45 - 49: I think that you should add these recent references to support your sentence.
Response 3: Thank you for your suggestion. We have added a new reference article to this paragraph.
Therefore, climate models are not only an effective tool for describing the interaction of the five major circles of the climate system and its impact on climate change research, but also an important tool for humans to be able to grasp the evolution of the climate system, study the characteristics and behavior of the current climate, and predict and anticipate future climate change, and also provide an important basis for the description of human and wildlife activities and environmental protection.
Point 4: Lines 112- 125: Please. describe better your hypothesis and predictions.
Response 4: We apologize for the problems in the original manuscript. We have modified the problem in this paragraph.
Extreme climate events and extreme weather events are collectively referred to as extreme events. As a rare event with low probability, extreme events are characterized by strong paroxysm and great harm. The increase of its frequency and intensity will have a serious impact and loss on society, human life, economy and natural ecosystem.
Point 5: Lines 179- 181: Lines 45 - 49: I think that you should add these recent references to support your methods Correlation analysis: correlation analysis is a method for analyzing the correlation between two variables, and is an impotant method often used in the analysis of the causes of we ather and climate change processes [27]. I would like to suggest.
Response 5: Thank you for your rigorous comment. We have added more references on the relevant coefficients.
Point 6: Lines 218- 425: Please, add the scale and the north symbol in all the map figures in the results.
Response 6: We deeply appreciate the reviewer’s suggestion, we are very sorry that we did not focus on this point. We have included these elements in the corresponding pictures.
Point 7: Lines 472 - 503: This section of the manuscript should be greatly expanded. Please, discuss your results comparing them also with other studies already published.
Response 7: Thank you for your suggestion. We have expanded the conclusion section to make it more detailed.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Paper "Analysis of the simulation capability of the extreme events in Northwest China from the BCC-CSM2 model" presents research related to the application of models used in hydrology, in general. The paper also presents a real case study.
Several suggestions will be emphasized.
Suggestion 1:
According to the rules of writing a scientific paper, key words cannot be words from the title of the scientific paper. Changes are suggested.
Suggestion 2:
The authors mainly gave an overview of the research of the proposed methodology in China. It is suggested to add some more references that include other case studies with the same or different climatic conditions.
Suggestion 3:
On line 82 in the text of the scientific paper, only references "11-17" are listed. It does not correspond to the rules of writing a scientific paper. It is suggested to add the core of the research done by the cited authors.
Suggestion 4:
In the "Introduction" chapter, the starting hypotheses of the research should be emphasized in more detail.
Suggestion 5:
Figure 1 is a "mute map". It is suggested to add details related to topographic marks - contours, elevation, settlement and various types of boundary lines (international, provincial, etc.), etc. On the other hand, it is also necessary to put a legend for the map.
Suggestion 6:
The methodology is very briefly described. References for the applied methodology are also missing. This chapter needs to be refined in detail.
Suggestion 7:
The results chapter is somewhat adequately presented (it should be harmonized with the previous suggestion), but why is the discussion separated and presented in such a small volume? It is suggested that the chapters be combined and that the discussion of the obtained research be carried out in parallel; I think it's a better way for readers.
Suggestion 8:
The conclusion is not adequately presented. There is no need to repeat the details from previous chapters. It is suggested to specifically add items that describe the scientific contribution of the research. On the other hand, also mention the contribution to the academic community.
I am also adding an interesting paper that inspired me on this topic.
Wei, L., Xin, X., Xiao, C. et al. Performance of BCC-CSM Models with Different Horizontal Resolutions in Simulating Extreme Climate Events in China. J Meteorol Res 33, 720–733 (2019). https://doi.org/10.1007/s13351-019-8159-1
Author Response
Point 1: According to the rules of writing a scientific paper, key words cannot be words from the title of the scientific paper. Changes are suggested.
Response 1: Thank you for your rigorous comment. We have changed the keywords to BCC-CSM2 model; .Northwest China; extreme climate indices; extreme high/low temperature; extreme precipitation.
Point 2: The authors mainly gave an overview of the research of the proposed methodology in China. It is suggested to add some more references that include other case studies with the same different climatic conditions.
Response 2: We apologize for the problems in the original manuscript. We have added more references.
In order to keep up with the development of climate coupled models, the National Climate Center has been working on the development of the Climate System Model (BCC_CSM) and has been pushing forward. Based on three sets of daily reanalysis data, Zhang et al. [9] evaluated the simulation capability of the medium-resolution BCC-CSM2-MR and the individual atmospheric model BCC-AGM3-MR for blocking high pressure in the northern hemisphere at middle and high latitudes. The frequency of blocking high pressure in winter in Eurasia, especially in the Ural Mountains, is reduced, and the frequency of blocking high pressure in spring in the North Pacific is increased, and the simulation deviation is reduced. Xin et al. [10] presented the basic information of the Earth System Model (BCC-ESM-1.0), the medium-resolution BCC-CSM2-MR, and the high-resolution BCC-CSM2-HR, and evaluated the results of the historical experiments of the CMIP6 program in which the BCC-CSM2-MR participated, which showed that the results on the multi-year temperature and precipitation in the Chinese region. The results show that the BCC-CSM2-MR has better simulation capability for multi-year temperature and precipitation evolution in China than the previous version. Sang et al. [11] evaluated two medium-resolution BCC-CSM models for the simulation of soil moisture on the surface of Eurasia at the annual seasonal scale and showed that the BCC-CSM-MR was better at reproducing the mean state of climate and the standard deviation of soil moisture with better correlation and significantly less bias, and the correlation coefficient of this model exceeded that of most models in CMIP6. Jiang et al. [12] used 26 models from the CMIP6 program, including BCC-CSM-MR, to assess the ability to simulate extreme temperature changes at mid- and high-latitudes in Asia, and the results show that the models are in good agreement for simulating the climate mean state.
Point 3: On line 82 in the text of the scientific paper, only references “11-17" are listed. It does not correspond to the rules of writing a scientific paper. It is suggested to add the core of the research done by the cited authors.
Response 3: Thank you for your suggestion. We have added a description of the study about the citing author.
Northwest China, including the five provinces of Xinjiang, Qinghai, Gansu, Ningxia and Shaanxi, is a climate-sensitive area prone to extreme events due to its unique terrain topography and also the focus of meteorologist. Based on statistical methods and numerical simulation methods, a great deal of work has been done on the distribution characteristics [13-15], change reasons [16, 17] and water resources [18, 19] of arid climate in Northwest China.
Point 4: In the "Introduction" chapter, the starting hypotheses of the research should be emphasized in more detail.
Response 4: We are grateful for the suggestion. We have modified the description in the introduction.
Extreme climate events and extreme weather events are collectively referred to as extreme events. As a rare event with low probability, extreme events are characterized by strong paroxysm and great harm. The increase of its frequency and intensity will have a serious impact and loss on society, human life, economy and natural ecosystem. In the context of global warming, the analysis and evaluation of the simulation results of extreme events in Northwest China based on the climate system model can not only test the accuracy of the model simulation results and provide reference for improving the simulation capability of the model, but also have important significance and practical value for the early warning and prevention of meteorological disasters in Northwest China. Therefore, this paper will use different resolution versions of the BCC-CSM2 model developed by the National Climate Center to compare and demonstrate the improvement of the model simulation capability due to the improvement of the model resolution, evaluate the simulation capability on extreme events in Northwest China, show the similarity of climate models for extreme events, further improve the understanding of climate change laws in Northwest China, and improve the model simulation capability. We will ensure the steady development of social and agricultural in Northwest China.
Point 5: Figure 1is a "mute map". It is suggested to add details related to topographic marks - contours, elevation, settlement and various types of boundary lines (international, provincial, etc.), etc. On the other hand, it is also necessary to put a legend for the map.
Response 5: Thank you for your rigorous comments. We have modified Figure 1 and added some details.
New Figure 1
Point 6: The methodology is very briefly described. References for the applied methodology are also missing. This chapter needs to be refined in detail.
Response 6: Thank you for your suggestion. We have added a detailed description of how to use it, along with references.
Percentile method, which is more common at home and abroad, is to determine the extreme precipitation threshold by ranking the precipitation at a station for a certain time period with the 90th, 95th or 99th percentile, and then determine the extreme precipitation event based on the extreme precipitation threshold. For regions with small spatial scale, it is reasonable to use the absolute critical value method to define the threshold, while for regions with large spatial scale, it is reasonable to use percentile method to define the threshold. The specific approach is as follows: the month-by-month precipitation of all grid points in the study area from 1961 to 2014 is arranged in ascending order, and the value of the 95th percentile is used as the extreme precipitation threshold of the point, and precipitation greater than this precipitation threshold is considered extreme and is identified as an extreme precipitation event.
Extreme climate indices, which can directly reflect climate change, are the common tool for studying regional climate change [34, 35] and comparing climate model results. In order to reflect the changes of extreme temperature, eight extreme climate indices defined by ETCCDI are used, including annual maximum daily maximum temperature, annual maximum daily minimum temperature, annual minimum daily maximum temperature, annual minimum daily minimum temperature, cold night, cold day, warm night and warm day, of which the first four indices are intensity indices and the last four are frequency indices, which are defined in detail in Table 1.
Point 7: The results chapter is somewhat adequately presented (it should be harmonized with the previous suggestion), but why is the discussion separated and presented in such a small volume? It is suggested that the chapters be combined and that the discussion of the obtained research be carried out in parallel; I think it's a better way for readers.
Response 7: We are grateful for the suggestion. We have modified this chapter to make the presentation of its conclusions more intuitive.
Point 8: The conclusion is not adequately presented. There is no need to repeat the details from previous chapters. It is suggested to specifically add items that describe the scientific contribution of the research. On the other hand, also mention the contribution to the academic community.
Response 8: We apologize for the problems in the original manuscript. We have rewritten the conclusion in the revision so that it better describes the ideas of the article.
Author Response File: Author Response.pdf
Reviewer 3 Report
The paper only describes and compares three climatic models. It does not contribute significantly to the global remote sensing literature, but it may be used for its sound methodology. The authors must justify the novelty of the paper.
The paper text is written relatively well, but I suggest authors work on the following recommendations for better representation.
Critical:
l I am not quite sure the authors have spotted the right journal as the contribution of remote sensing imagery has not been highlighted well. They have primarily relied on climatic statistical formulas. More RS-based materials are needed.
l I strongly suggest that the text be edited for English grammar. Statements are unusually long and unintegrated (e.g., lengthy lines 9-15; lines 31-36; lines 36-43; etc). (line 112: “Extreme weather events and extreme weather events are collectively referred to as extreme events”) (line 170: “This method, which is more common at home and abroad”, it is a journalist wording)
l More relevant papers outside China can enrich the paper as I cannot see any papers from other countries.
General:
l Please link Figure 1 to a larger view and link to the China map. It can help readers to see the exact location of the study area nationally.
l Please describe why your dataset is limited to 1961 to 2014. You have mentioned that “extreme weather events occur mostly in recent years” (line 199).
l Table 2 describes a few events. Provide reason.
l Provide one line space between all ‘tables/figure caption’ and ‘the main text’.
l Relocate lines 221 to 226 before Figure 2, under section 3.1.
l Shorten the description of lines 227 to 277.
Author Response
Point 1: I am not quite sure the authors have spotted the right journal as the contribution of remote sensing imagery has not been highlighted well. They have primarily relied on climatic statistical formulas. More RS-based materials are needed.
Response 1: Our articles are written for the Special Issue “Precipitation and Evapotranspiration Mechanisms in Drylands and Their Remote Sensing Retrieval & Simulation”, contains topics “Drought and flood assessment and monitoring”.
Point 2: I strongly suggest that the text be edited for English grammar. Statements are unusually long and unintegrated (e.g. lengthy lines 9-15; lines 31-36; lines 36-43; etc). (line 112: "Extreme weather events and extreme weather events are collectively referred to as extreme events') (line 170: "This method, which is more common at home and abroad" it is a journalist wording)
Response 2: We apologize for the problems in the original manuscript. We have revised the phrasing problems in the text to make it more fluent.
Point 3: More relevant papers outside China can enrich the paper as I cannot see any papers from other countries.
Response 3: Thank you for your suggestion. We have added more references from different countries to our article.
Point 4: Please link Figure 1 to a larger view and link to the China map. It can help readers to see the exact location of the study area nationally.
Response 4: Thank you for your rigorous comment. We have added the location markers of the Northwest region in China to Figure 1.
Point 5: Please describe why your dataset is limited to 1961 to 2014. You have mentioned that "extreme weather events occur mostly in recent years' (line 199).
Response 5: We deeply appreciate the reviewer’s suggestion. We have added some description in the revised manuscript.
Because extreme weather events occur mostly in recent years and the daily data from BCC-CSM2-HR is only from 2004 to 2014, the actual observation data (daily maxi-mum temperature, daily minimum temperature and daily precipitation) in the last 11 years (2004-2014) in Northwest China are averaged and then arranged in descending order, and three typical extreme weather events larger than the 95th percentile of their corresponding elements are selected.
Point 6: Table 2 describes a few events. Provide reason.
Response 6: We are grateful for the suggestion. We have added a selection method for extreme events.
Because extreme weather events occur mostly in recent years, the daily data from BCC-CSM2-HR is only from 2004 to 2014. The actual observation data (daily maximum temperature, daily minimum temperature and daily precipitation) in the last 11 years (2004-2014) in Northwest China are averaged and then arranged in descending order, and three typical extreme weather events larger than the 95th percentile of their corresponding elements are selected. The resolution of the output data by BCC-CSM2-HR mode is interpolated to be the same as the observed value, and the corresponding events are found for comparison, so as to evaluate the simulation performance of BCC-CSM2-HR model for extreme weather events in Northwest China.
Point 7: Provide one line space between all tables/figure caption' and "the main text.
Response 7: Thank you for your suggestion. We have fixed the spacing issue in the article.
Point 8: Relocate lines 221 to 226 before Figure 2, under section 3.1.
Response 8: We are grateful for the suggestion. We have modified the order between the graphics.
Point 9: Shorten the description of lines 227 to 277.
Response 8: Thank you for your suggestion. We have shortened the description of this paragraph.
The ability to reproduce the spatial distribution of summer precipitation in Northwest China at different time scales is an important criterion to discern the model simulation capability. The spatial distribution of precipitation in Northwest China from the observation, the simulated differences between the BCC-CSM2-MR, the BCC-CSM2-HR and the observation in each season during 1961~2014 is given in Figure 3. For the annual precipitation, the large value areas of observed annual precipitation in Northwest China are mainly in eastern Qinghai, southeastern Gansu, southern Shaanxi, and the Tianshan region, with values above 400 mm, while the Tarim and Qaidam basins are the areas with the least annual precipitation, less than 80 mm. However, the deviation of the BCC-CSM2-HR is slightly smaller and closer to the observed value, and has effectively improved the annual precipitation in the Kunlun Mountains and Qilian Mountains, and reduced the simulated deviation in these areas to less than 120 mm. But the BCC-CSM2-HR has large simulated deviations in southern Qinghai and southern Gansu, indicating that the model needs further improvement. The precipitation in Northwest China is mainly concentrated in summer. Except for the precipitation in Xinjiang, the summer precipitation in the rest of the regions simulated by both resolution models is high, and the precipitation simulated by the BCC-CSM2-HR is low with a wider range and its deviation is not large. The pattern correlation coefficient of precipitation between the simulation and the observation is higher in summer (0.66 in BCC-CSM2-MR, 0.75 in BCC-CSM2-HR, hereafter) and autumn (0.58, 0.68) than in winter (0.28, 0.32) and spring (0.37, 0.52), and the BCC-CSM2-HR is still better than the BCC-CSM2-MR. Overall, the distributions of precipitation in Northwest China for each season simulated by the BCC-CSM2-HR are better and closer to the observation than the BCC-CSM2-MR.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have completely ignored my suggested references.
I again suggested them to add these important references:
Lines 45 – 49: I think that you should add these recent references to support your sentence “Therefore, climate models are not only an effective tool for describing the study of the interaction of the five major circles of the climate system and their impact on climate change, but also an important tool for humans to be able to grasp the evolution of the climate system, study the characteristics and behavior of the current climate, and predict and anticipate future climate change”. I would like to suggest:
Ali, H., et al. (2021). Expanding or shrinking? range shifts in wild ungulates under climate change in Pamir-Karakoram mountains, Pakistan. PloS one, 16(12), e0260031.
Tang, X., et al. (2021). Maximum entropy modeling to predict the impact of climate change on pine wilt disease in China. Frontiers in Plant Science, 12, 652500.
Lines 179 – 181: Lines 45 – 49: I think that you should add these recent references to support your methods “Correlation analysis: correlation analysis is a method for analyzing the correlation between two variables, and is an important method often used in the analysis of the causes of weather and climate change processes [27]”. I would like to suggest:
Anand, V., et al. (2021). Predicting the current and future potential spatial distribution of endangered Rucervus eldii eldii (Sangai) using MaxEnt model. Environmental Monitoring and Assessment, 193(3), 1-17.
Author Response
Point 1: Lines 45 - 49: I think that you should add these recent references to support your sentence.
Response 1: We apologize for the problems in the revised manuscript. In the second revised manuscript, we have added the reference articles suggested by you to this paragraph.
Therefore, climate models are not only an effective tool for describing the interaction of the five major circles of the climate system and its impact on climate change research, but also an important tool for humans to be able to grasp the evolution of the climate system, study the characteristics and behavior of the current climate [4-6], and predict and anticipate future climate change [5, 7, 8], and also provide an important basis for the description of human and wildlife activities and environmental protection [4, 6].
- Ali, H.; Din, J.U.; Bosso, L.; Hameed, S.; Kabir, M.; Younas, M.; Nawaz, M.A. Expanding or shrinking? range shifts in wild ungulates under climate change in Pamir-Karakoram mountains, Pakistan. PLoS ONE, 2021, 16, e0260031.
- Tang, X.G.; Yuan, Y.D.; Li, X.M.; Zhang, J.C. Maximum entropy modeling to predict the impact of climate change on pine wilt disease in China. Frontiers in Plant Science, 2021, 12, 652500.
Point 2: Lines 179- 181: Lines 45 - 49: I think that you should add these recent references to support your methods Correlation analysis: correlation analysis is a method for analyzing the correlation between two variables, and is an impotant method often used in the analysis of the causes of we ather and climate change processes [27]. I would like to suggest.
Response 2: Thank you for your rigorous suggestion. We have added the last references on the correction coefficients.
The correlation analysis is a method for analyzing the correlation between two variables, and is an important method often used in the analysis of the causes of weather and climate change processes [35]. Anand et al. [36] used the Pearson correlation matrix analysis to eliminate the multi-collinearity between the variables and improve the model performance.
- Anand, V.; Oinam, B.; Singh, I.H. Predicting the current and future potential spatial distribution of endangered Rucervus eldii eldii (Sangai) using MaxEnt model. Environmental Monitoring and Assessment, 2021, 193, 1-17.
Author Response File: Author Response.pdf
Reviewer 2 Report
In the newly submitted version of the paper, the authors made an effort to improve the quality of the paper. Several suggestions will be emphasized.
- I suggest adding "Case Study of ..." in the title.
- The same words that are in the title of the paper are still repeated in relation to the key words.
- The abstract has too many redundant details. They are more important for the description of the methodology and the results. It must be clear, specific/concise.
- Figure 1 is still a "mute map". The authors have only bolded the lines; Please see the proposal in the previous report about what a topographic map can contain.
- It is suggested to create a Results and Discussion chapter, because it is logical. The Conclusion chapter should be separate and contain the specific scientific contribution of the research.
Author Response
Point 1: I suggest adding “Case Study of …” in the title.
Response 1: Thank you for the excellent suggestion. We have changed the title to “Simulation performance and case study of extreme events in Northwest China from BCC-CSM2 model “.
Point 2: The same words that are in the title of the paper are still repeated to the key words.
Response 2: We apologize for the problems in the revised manuscript and have rewritten the key words again.
Keywords: Arid area; extreme climate indices; precipitation threshold; extreme high/low temper-ature; extreme precipitation
Point 3: The abstract has too many redundant details. They are more important for the description of the methodology and the results. It must be clear, specific/concise.
Response 3: We are grateful for the suggestion. We have reduced the summary to make it simpler and clearer.
Abstract: The BCC-CSM2 model is the second generation of the Beijing Climate Center Climate System Model developed by the National Center of China Meteorological Administration. Using the outputs of two resolution versions of the BCC-CSM2 model: BCC-CSM2-MR and BCC-CSM2-HR, the simulation performance on the climate characteristics in Northwest China is compared. The BCC-CSM2-HR has a better ability to simulate the detailed distribution of the climate averaged state of temperature and precipitation in Northwest China, and can delineate the influence of topography in detail. The extreme events in Northwest China are further evaluated using the BCC-CSM2-HR and the observation data from the China Meteorological Data Center. The BCC-CSM2-HR can well simulate the spatial distribution of extreme climate events in North-west China, and the spatial distribution of TXx, TNx, TXn, and TNn in Northwest China show closer proximity to the observation than that of TX90p, TN90p, TX10p, TN10p, even extreme heavy precipitation. The case study of the extreme weather events shows that the BCC-CSM2-HR has the best simulation performance for extreme high temperature events in Northwest China, followed by extreme low temperature events, and the worst simulation ability for extreme pre-cipitation events.
Point 4: Figure 1 is still a "mute map". The authors have only bolded the lines. Please see the proposal in the previous report about what a topographic map can contain.It is suggested to add details related to topographic marks - contours, elevation, settlement and various types of boundary lines (international, provincial, etc.), etc. On the other hand, it is also necessary to put a legend for the map.
Response 4: Thank you for your rigorous comments. We have made further modifications to Figure 1 to make it compliant.
Point 5: It is suggested to create a Results and Discussion chapter, because it is logical. The Conclusion chapter should be separate and contain the specific scientific contribution of the research.
Response 5: We apologize for the problems in the revised manuscript. In the second revision, we have put the discussion to the Results and Discussion chapter and found it better.
Author Response File: Author Response.pdf
Reviewer 3 Report
Thank you for responding to inquiries.
Author Response
Thanks for your comments and suggestions.
