Near Future Projection of Indian Summer Monsoon Circulation under 1.5 °C and 2.0 °C Warming
Round 1
Reviewer 1 Report
This article investigated the response of ISM to temperature rise under 1.5K and 2.0K by using CESM model data. They found some interesting results in their study. However, in order to improve it, the authors need to do some work and answer the following questions.
(1) The presentation is poor. It is too easy to list the differences in the effects of warming. I don't trust these results unless the authors show me some more reliable facts. I need to know if the atmospheric circulation system has changed position and strength on a larger scale as a result of global warming. The authors may consider including some pictures in the article, such as climatology and other elements of the 500hPa geopotential height.
(2) The study does not explain well the mechanism of the effect of global warming on ISM. They should give more physical explanations why and how the ISM is changing.
(3) Since the article mentioned East Asian summer monsoon, why they did not cite relevant papers? For example, Wang et al. (2001, JSMJ) analyzed the changes in the EASM circulation caused by ENSO that may occur more frequently due to global warming. The position of the Pacific subtropical high pressure has changed significantly.
(4) The abbreviation "IV" should be changed to "InV" or other words to avoid confusion with the number 4.
(5) Lines 119-131. Formatting needs to be adjusted.
Author Response
Reply to Reviewer #1
Near-future Projection of Indian Summer Monsoon Circulation under 1.5⁰C and 2.0⁰C Warming
Devanil Choudhury, Debashis Nath and Wen Chen.
We would like to thank the respected reviewer for giving his/her times and providing his/her valuable comments. We hereby modified our manuscript. Changes in the revised manuscript are indicated by ‘red’ color.
Comment 1: The presentation is poor. It is too easy to list the differences in the effects of warming. I don't trust these results unless the authors show me some more reliable facts. I need to know if the atmospheric circulation system has changed position and strength on a larger scale as a result of global warming. The authors may consider including some pictures in the article, such as climatology and other elements of the 500hPa geopotential height.
Reply 1: Thank you for this suggestion, we tried to improve our presentation by modifying manuscript. Unfortunately, we did not get the data from CEMS1-low warming experiments as they are no longer accessible openly. We wish to get your consideration in this matter.
Comment 2: The study does not explain well the mechanism of the effect of global warming on ISM. They should give more physical explanations why and how the ISM is changing.
Reply 2: Line 283-298, we added some possible mechanisms & few more sentences included for the east Asian scenario. We tried our best regarding this.
Comment 3: Since the article mentioned East Asian summer monsoon, why they did not cite relevant papers? For example, Wang et al. (2001, JSMJ) analyzed the changes in the EASM circulation caused by ENSO that may occur more frequently due to global warming. The position of the Pacific subtropical high pressure has changed significantly.
Reply 3: Thanks, in Line 200-204: Wang et al. (2001) added. Apart from this many more references have been added now in Introduction, Data & Methods, & Results sections.
Comment 3: The abbreviation "IV" should be changed to "InV" or other words to avoid confusion with the number 4.
Reply 4: Thank you. IV is changed to InV now as per your suggestion.
Comment 5: Lines 119-131. Formatting needs to be adjusted.
Reply 5: Formatting is done, Line: 154, 160 & 165.
Reviewer 2 Report
Comments to the Author
Review of Article “Near-future Projection of Indian Summer Monsoon Circulation 2 under 1.5⁰C and 2.0⁰C Warming” by Devanil Choudhury, Debashis Nath and Wen Chen.
This article deals with the projections of Indian Summer Monsoon response to 1.5⁰C/ 2.0⁰C warming scenarios during the period 2021—2050. For the analysis 11 member ensembles of the Community Earth System Model (CESM) mode were used. The analysis focuses on jjas (June-July-August-September) period under 1.5⁰C/ 2.0⁰C warming scenarios. This study contributes to the better understanding of the projections of ISM and the mechanism that acts as a driver for the changes during the near-future.
In my opinion, this work is valuable but the authors should improve and, discuss a bit more (add literature in) some points. I believe that the authors should provide clearer the data and variables that they used in the section of “Data and Methods”. Additionally, the statistical test that was used in the trend analysis it is not clear to me. Results are well written and show good elements regarding the projections of ISM (2021-2050) providing a mechanism that explains the main findings. In my opinion, the authors should add a short discussion regarding the results in this section.
I believe that this article has the potential to be published in Atmosphere Journal after a major revision. I suggest a bit extension of literature in Introduction as well as of discussion over the results section. I believe that these points can improve more this valuable work. Also the authors could take under consideration the suggestions and comments below.
Abstract
In my opinion, the abstract is well written and clear for the reader.
Introduction
A general comment: I recommend the authors extend the literature regarding the ISM and future projections in order to enrich this work. For example, there are previous papers that are referred to the mechanism and evolution of ISM during the future using model simulations. In their analysis the authors analyze data from the CESM1 model that uses a CMIP5 model. In my opinion, a small paragraph regarding the result of previous works regarding the future projections and variability of ISM can improve this interesting work. There are previous studies that investigate the ISM using CMIP5 simulations, observations and other data set.
1. In page 2, lines 88-94. I believe that it would be better to move these lines (or to rephrase this lines) in the section of “Data and Methods”. In my opinion, it is important to give in a clear way the data and tools that the authors used in the study in this section.
Data and Methods
In my opinion, this section needs some improvements. Some points are not so clear to me. I believe that should be given elements regarding the spatial - temporal resolution of model, the period of the analysis and the variables that used in this work.
· The authors give some information regarding the model simulation used here. Could you please provide more info regarding the spatial and temporal resolution of these simulations? Additionally, I suggest the authors refer in this section the period (jjas period) and that their analysis is focused on the years from 2021 to 2050 (near-future period).
I suggest the authors rephrase a bit the lines 95-98 with the following “….. was designed to assess the historical (1920-2005) and projected climate changes (2006–2100) in the presence of internal climate variability.”
· I recommend the authors give in the text the geographical domain of the studied region (ISM) in order to make it clearer to the reader.
1. In the final sentence of “Introduction” section the authors said that low level wind speed and precipitation used for the analysis.
I suggest the authors refer in the text the variables that analyzed in this study in the section of “Data and Methods”.
What about the SLP variable that you used in the Results section? The authors do not refer SLP in the paragraph of “Data and Methods”. Could you please clarify?
2. Page 3, Lines 102-116: The authors give some elements regarding the CESM-LE.
In my opinion, it will be valuable if the authors provide some literature elements regarding the use of a.) multimodel mean and b.) CESM-LE to study future projection trends. Of course the authors discuss about this issue in the conclusion section but I also suggest to enrich a bit more the section of “Data and Methods”. Additionally, I recommend the authors give some elements regarding the RCPs scenarios, the 1.5⁰C/ 2.0⁰C warming scenarios and the relation between them.
3. Page 3, lines 19-23: The authors present the linear trends estimated by a linear fit equation. Do the authors used a statistical significance test for the calculated trend analysis? Could you please clarify?
(Please also see my comments in the following section, “Results - comment 1”).
Results
The authors present their results in a well written way giving an explanation regarding their findings. I suggest a short discussion regarding their main results. It would be great of interest if the authors give a short discussion regarding the results of this work comparing to the results of other previous studies which have used other data sets.
1. Maybe I am missing something but it is not clear to me if the trends in the figures are statistically significant. Are the trends in colored areas in figures significant? (Please also see my comments in the section, “Data and Methods - comment 4”).
2. Page 6, lines 242-251. In this paragraph you said that ISM depends on north-south pressure gradient and you investigate the behavior of SLP.
In my opinion, you should give some elements regarding the SLP in the section of “Data and Methods”. If I understood correctly, it is the first time that the SLP is referred in this study. (Please also see my comments in the section, “Data and Methods - comment 2”).
Conlcusion
The conclusion section is clear and well written.
Some papers that may help the authors to further improve this work are the following:
• S. Sharmila, S. Joseph, A.K. Sahai, S. Abhilash, R. Chattopadhyay, Future projection of Indian summer monsoon variability under climate change scenario: An assessment from CMIP5 climate models, Global and Planetary Change, Volume 124, 2015, Pages 62-78, ISSN 0921-8181, https://doi.org/10.1016/j.gloplacha.2014.11.004
• Mishra, S.K., Sahany, S., Salunke, P. et al. Fidelity of CMIP5 multi-model mean in assessing Indian monsoon simulations. npj Clim Atmos Sci 1, 39 (2018). https://doi.org/10.1038/s41612-018-0049-1
• Preethi, B., Ramya, R., Patwardhan, S.K. et al. Variability of Indian summer monsoon droughts in CMIP5 climate models. Clim Dyn 53, 1937–1962 (2019). https://doi.org/10.1007/s00382-019-04752-x
• Lee, JY., Wang, B. Future change of global monsoon in the CMIP5. Clim Dyn 42, 101–119 (2014). https://doi.org/10.1007/s00382-012-1564-0
• Mishra, V., Thirumalai, K., Singh, D. et al. Future exacerbation of hot and dry summer monsoon extremes in India. npj Clim Atmos Sci 3, 10 (2020). https://doi.org/10.1038/s41612-020-0113-5
• Xin Huang, Tianjun Zhou, Andrew Turner, Aiguo Dai, Xiaolong Chen, Robin Clark, Jie Jiang, Wenmin Man, James Murphy, John Rostron, Bo Wu, Lixia Zhang, Wenxia Zhang, and Liwei Zou. The Recent Decline and Recovery of Indian Summer Monsoon Rainfall: Relative Roles of External Forcing and Internal Variability. Journal of Climate, 5035–5060, 2020. https://doi.org/10.1175/JCLI-D-19-0833.1
· Katzenberger, A., Schewe, J., Pongratz, J., and Levermann, A.: Robust increase of Indian monsoon rainfall and its variability under future warming in CMIP6 models, Earth Syst. Dynam., 12, 367–386, https://doi.org/10.5194/esd-12-367-2021 , 2021
• Menon, A., Levermann, A., Schewe, J., Lehmann, J., and Frieler, K.: Consistent increase in Indian monsoon rainfall and its variability across CMIP-5 models, Earth Syst. Dynam., 4, 287–300. https://doi.org/10.5194/esd-4-287-2013 , 2013
• Sanjiv Kumar, James L. Kinter, Zaitao Pan, Justin Sheffield. Twentieth century temperature trends in CMIP3, CMIP5, and CESM-LE climate simulations: Spatial-temporal uncertainties, differences, and their potential sources, JGR Atmospheres, https://doi.org/10.1002/2015JD024382 , 2016
• Qu, X., Huang, G. Different multi-year mean temperature in mid-summer of South China under different 1.5 °C warming scenarios. Sci Rep 8, 13794 (2018). https://doi.org/10.1038/s41598-018-32277-6
· Moon, S., Ha, KJ. Future changes in monsoon duration and precipitation using CMIP6. npj Clim Atmos Sci 3, 45 (2020). https://doi.org/10.1038/s41612-020-00151-w
· Kumar, K.K., Kamala, K., Rajagopalan, B. et al. The once and future pulse of Indian monsoonal climate. Clim Dyn 36, 2159–2170 (2011). https://doi.org/10.1007/s00382-010-0974-0
Author Response
Reply to Reviewer #2
We would like to thank the respected reviewer for giving his/her times and providing his/her valuable comments. We hereby modified our manuscript. Changes in the revised manuscript are indicated by ‘red’ color.
Comment 1: I recommend the authors extend the literature regarding the ISM and future projections in order to enrich this work. For example, there are previous papers that are referred to the mechanism and evolution of ISM during the future using model simulations. In their analysis the authors analyze data from the CESM1 model that uses a CMIP5 model. In my opinion, a small paragraph regarding the result of previous works regarding the future projections and variability of ISM can improve this interesting work. There are previous studies that investigate the ISM using CMIP5 simulations, observations, and other data set.
Reply 1: Thanks a lot for your comments, we have extended our literature in detail.
Comment 2: In page 2, lines 88-94. I believe that it would be better to move these lines (or to rephrase this lines) in the section of “Data and Methods”. In my opinion, it is important to give in a clear way the data and tools that the authors used in the study in this section.
Reply 2: Thank you for your suggestions. Data & Methods section is now thoroughly modified.
Data and Methods
In my opinion, this section needs some improvements. Some points are not so clear to me. I believe that should be given elements regarding the spatial - temporal resolution of model, the period of the analysis and the variables that used in this work.
Comment 3: The authors give some information regarding the model simulation used here. Could you please provide more info regarding the spatial and temporal resolution of these simulations? Additionally, I suggest the authors refer in this section the period (jjas period) and that their analysis is focused on the years from 2021 to 2050 (near-future period).
Reply 3: Spatial & temporal resolution have been added now, more details about model simulation have been included. Period and variables have also included (Line: 152-155).
Comment 4: I suggest the authors rephrase a bit the lines 95-98 with the following “….. was designed to assess the historical (1920-2005) and projected climate changes (2006–2100) in the presence of internal climate variability.”
Reply 4: This line has been removed now.
Comment 5: I recommend the authors give in the text the geographical domain of the studied region (ISM) in order to make it clearer to the reader.
Reply 5: Graphical domain in text form have been added now (Line 155).
Comment 6: In the final sentence of “Introduction” section the authors said that low level wind speed and precipitation used for the analysis. I suggest the authors refer in the text the variables that analyzed in this study in the section of “Data and Methods”.
Reply 6: Thanks for your suggestion, we now included all parameters which are used in this study.
Comment 7: What about the SLP variable that you used in the Results section? The authors do not refer SLP in the paragraph of “Data and Methods”. Could you please clarify?
Reply 7: SLP now included in Data & Methods section (Line: 153).
Comment 8: Page 3, Lines 102-116: The authors give some elements regarding the CESM-LE. In my opinion, it will be valuable if the authors provide some literature elements regarding the use of a.) multimodel mean and b.) CESM-LE to study future projection trends. Of course, the authors discuss about this issue in the conclusion section, but I also suggest enriching a bit more the section of “Data and Methods”. Additionally, I recommend the authors give some elements regarding the RCPs scenarios, the 1.5⁰C/ 2.0⁰C warming scenarios and the relation between them.
Reply 8: RCP and CESM1-low warming are discussed and modified at Line: 95-100 & 124-134
Comment 9: Page 3, lines 19-23: The authors present the linear trends estimated by a linear fit equation. Do the authors used a statistical significance test for the calculated trend analysis? Could you please clarify? (Please also see my comments in the following section, “Results - comment 1”).
Reply 9: Only linear trend is considered here; significant test is not incorporated.
Comment 10: The authors present their results in a well written way giving an explanation regarding their findings. I suggest a short discussion regarding their main results. It would be great of interest if the authors give a short discussion regarding the results of this work comparing to the results of other previous studies which have used other data sets.
Reply 10: In Introduction at Line: 70-86 previous studies have been discussed & at Line: 95-115 summary is discussed.
Comment 11: Maybe I am missing something, but it is not clear to me if the trends in the figures are statistically significant. Are the trends in colored areas in figures significant? (Please also see my comments in the section, “Data and Methods - comment 4”).
Reply 11: Same as Reply 7.
Comment 12: Page 6, lines 242-251. In this paragraph you said that ISM depends on north-south pressure gradient, and you investigate the behavior of SLP. In my opinion, you should give some elements regarding the SLP in the section of “Data and Methods”. If I understood correctly, it is the first time that the SLP is referred in this study. (Please also see my comments in the section, “Data and Methods - comment 2”).
Reply 12: SLP is now mentioned in Data & Methods section.
Comment 13: Some papers that may help the authors to further improve this work are the following:
- S. Sharmila, S. Joseph, A.K. Sahai, S. Abhilash, R. Chattopadhyay, Future projection of Indian summer monsoon variability under climate change scenario: An assessment from CMIP5 climate models, Global and Planetary Change, Volume 124, 2015, Pages 62-78, ISSN 0921-8181, https://doi.org/10.1016/j.gloplacha.2014.11.004
- Mishra, S.K., Sahany, S., Salunke, P. et al. Fidelity of CMIP5 multi-model mean in assessing Indian monsoon simulations. npj Clim Atmos Sci 1, 39 (2018). https://doi.org/10.1038/s41612-018-0049-1
- Preethi, B., Ramya, R., Patwardhan, S.K. et al. Variability of Indian summer monsoon droughts in CMIP5 climate models. Clim Dyn 53, 1937–1962 (2019). https://doi.org/10.1007/s00382-019-04752-x
- Lee, JY., Wang, B. Future change of global monsoon in the CMIP5. Clim Dyn 42, 101–119 (2014). https://doi.org/10.1007/s00382-012-1564-0
- Mishra, V., Thirumalai, K., Singh, D. et al. Future exacerbation of hot and dry summer monsoon extremes in India. npj Clim Atmos Sci 3, 10 (2020). https://doi.org/10.1038/s41612-020-0113-5
- Xin Huang, Tianjun Zhou, Andrew Turner, Aiguo Dai, Xiaolong Chen, Robin Clark, Jie Jiang, Wenmin Man, James Murphy, John Rostron, Bo Wu, Lixia Zhang, Wenxia Zhang, and Liwei Zou. The Recent Decline and Recovery of Indian Summer Monsoon Rainfall: Relative Roles of External Forcing and Internal Variability. Journal of Climate, 5035–5060, 2020. https://doi.org/10.1175/JCLI-D-19-0833.1
- Menon, A., Levermann, A., Schewe, J., Lehmann, J., and Frieler, K.: Consistent increase in Indian monsoon rainfall and its variability across CMIP-5 models, Earth Syst. Dynam., 4, 287–300. https://doi.org/10.5194/esd-4-287-2013 , 2013
- Sanjiv Kumar, James L. Kinter, Zaitao Pan, Justin Sheffield. Twentieth century temperature trends in CMIP3, CMIP5, and CESM-LE climate simulations: Spatial-temporal uncertainties, differences, and their potential sources, JGR Atmospheres, https://doi.org/10.1002/2015JD024382 , 2016
- Qu, X., Huang, G. Different multi-year mean temperature in mid-summer of South China under different 1.5 °C warming scenarios. Sci Rep 8, 13794 (2018). https://doi.org/10.1038/s41598-018-32277-6
- Moon, S., Ha, KJ. Future changes in monsoon duration and precipitation using CMIP6. npj Clim Atmos Sci 3, 45 (2020). https://doi.org/10.1038/s41612-020-00151-w
- Kumar, K.K., Kamala, K., Rajagopalan, B. et al. The once and future pulse of Indian monsoonal climate. Clim Dyn 36, 2159–2170 (2011). https://doi.org/10.1007/s00382-010-0974-0
Reply 13: Thanks a lot for your suggestion, we have added some references (such as Sharmila et al., 2015; Moon & Ha, 2020, etc.) from your list.
Reviewer 3 Report
Review of “Near-future Projection of Indian Summer Monsoon Circulation under 1.5oC and 2.0oC Warming” by Devanil Choudhury et al.
In this study, the authors investigated the Indian Summer Monsoon (ISM) response to low (1.5ºC) and medium (2.0ºC) warming scenarios during the period 2021—2050 by utilizing 11 member ensembles of the state-of-the-art Community Earth System Model (CESM) model. They concluded that under a 1.5ºC warming scenario, the ISM circulation will weaken, precipitation will exhibit a decreasing trend, while ISM precipitation and circulation will strengthen under the 2.0ºC warming scenario. The authors further provided plausible reasons for the strengthening of ISM under the 2.0ºC warming scenario and they highlighted the role of the South China Sea (SCS) anticyclone and a high-pressure center near the Philippine Island. The research topic is of scientific interest and this is an interesting paper regarding the Indian summer monsoon. The presentation is very clear and the supported analysis looks good. Thus, I recommended the manuscript for publication in the Atmosphere journal with some minor text corrections.
Comments:
Lines 28-35: I suggest adding some references. Almost every sentence between lines 28-35 needs a citation.
Lines 58-60: 'The second half of the twentieth century was a period of an unprecedented increase in GHGs and aerosol concentration — so an attempt to link these changes with modeled monsoon responses to anthropogenic warming up to the middle of the twenty-first century'. Please add some references.
In Figures, the text regarding subplots (a) and (b) are not visible. Please make the font bigger size.
Author Response
Reply to Reviewer #3
We would like to thank the respected reviewer for giving his/her times and providing his/her valuable comments. We hereby modified our manuscript. Changes in the revised manuscript are indicated by ‘red’ color.
Comment 1: Lines 28-35: I suggest adding some references. Almost every sentence between lines 28-35 needs a citation.
Reply 1: Thank you for your suggestion. Several references have been added now in Introduction & Result sections.
Comment 2: Lines 58-60: 'The second half of the twentieth century was a period of an unprecedented increase in GHGs and aerosol concentration — so an attempt to link these changes with modeled monsoon responses to anthropogenic warming up to the middle of the twenty-first century'. Please add some references.
Reply 2: We deleted this line as we did not find the exact reference, also it is not necessary.
Comment 3: In Figures, the text regarding subplots (a) and (b) are not visible. Please make the font bigger size.
Reply 3: Thanks. All the figures have been modified and fixed now.
Round 2
Reviewer 1 Report
They answered most my questions. I recommend the minor revision after solving the remaining problem. The editors will make a judgment on this issue.
Author Response
Thanks for your suggestion. Manuscript has now been throughly checked, English has been polished. Presentation has been improved a bit.
Reviewer 2 Report
Regarding the article “Near-future Projection of Indian Summer Monsoon Circulation under 1.5C and 2.0C Warming” by Devanil Choudhury, Debashis Nath, Wen Chen, I believe that the authors have satisfactory addressed all the issues.
Author Response
Thanks for giving your valuable time for this review process. We have throughly checked & polished our English using in our manuscript.
