the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 22 May 2024
The interprovincial green water flow in China and its tele-connected effects on socio-economy
Abstract. Green water (terrestrial evapotranspiration), flowing from source regions and precipitates downwind via moisture recycling, generates surface water resources and sustains socio-economy in sink regions. However, unlike blue water, there has been limited assessment of green water flows and their tele-connected effects on socio-economy. This study used the moisture tracking dataset of 2008–2017 to quantify interprovincial green water flows in China and their socio-economic contributions. Results reveal a complex flow network where green water of each province reciprocally exchanges with each other. Despite self-recycling, green water from source provinces mainly forms precipitation in neighboring provinces, with average interprovincial flow directions from west to east and south to north. About 56 % of total green water exported from 31 provinces retains at home and contributes 43 % of precipitation in China. Our assessments show that green water from source provinces embodies substantial socio-economic values for downwind provinces with regionally varying importance. Western provinces are the largest contributors to surface water resources while southwestern and central provinces embody the highest GDP, population, and food production. About 40 % surface water resources, 45 % GDP, 46 % population, and 50 % food production of China are supported by green water from 31 provinces. There is an overall increase in embodied socio-economic value of green water flow from source to sink provinces, suggesting that less developed provinces effectively support the higher socio-economic status of developed provinces through green water supply. The results emphasize the substantial tele-connected socio-economic values of green water and the need to incorporate it for a more comprehensive and effective water resources management.
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RC1: 'Comment on egusphere-2024-1420', Anonymous Referee #1, 19 Jun 2024
Sang et al. studied the interprovincial connections of green water. They quantified this by calculate the precipitation of each province from the green water inside or outside the province. The work is based on the data generated from a previous particle tracking work. Authors connect the results with social-economic effects, which is very interesting and novel. The structure and writing of the paper are clear. However, I have some thoughts as follows:
- I don’t think authors have clear enough introduction about how they connect the green water with the social-economic value. The introduction is in lines 140-175, but not clear. There are even no dimensions of the variables, and it is hard to know the relationship between different variables in the equations.
- It looks like authors assume linear relationships between water and all the social-economic indices. I am not quite sure if this is rigorous. For example, whether the food productivity has the positive, linear relationship with water? Similar question to other social-economic indices.
- For the sections of sources and sinks of green water (sections 3.1 and 3.2), it is hard to say they are really novel as it looks like some known results with a new wrapper. You are talking about the evapotranspiration circulation by adding the ‘interprovincial’ concept.
- Authors said the data are high quality data from previous studies. I think a bit more introduction is necessary.
- It is a long-term dataset. So why not analyze the temporal variations of these teleconnections? I think this is more important to audience. The average state is also important, but they are the natural pattern which are caused by the long-term climatic conditions. We should know this basic pattern, but we cannot change it much. The more important thing is the temporal variations which represent the variations caused by some interannual variations of natural conditions or by man-made climate change. This is important to inform the future social-economic development, e.g., if such variations are good or bad and if we need actions to control or facilitate such variations.
I suggest major revision of this manuscript.
Citation: https://doi.org/10.5194/egusphere-2024-1420-RC1 -
AC1: 'Reply on RC1', Shan Sang, 15 Aug 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-1420/egusphere-2024-1420-AC1-supplement.pdf
-
RC2: 'Comment on egusphere-2024-1420', Anonymous Referee #2, 03 Jul 2024
The paper presents a novel and insightful approach to connect green water flows to their economic value across different provinces in China. The manuscript is well-structured and written. However, there are a few points that could be clarified and improved to enhance the overall impact and clarity of the study.
- The use of the UTrack dataset for processing and tracking the green water flow is commendable. But, the uncertainties associated with the input precipitation data (P) in the forward-tracking process need further elaboration.
- It would be good to include the processing scripts for the UTrack dataset and a clearer explanation how you got from the dataset to the data that is used in the already included Python notebook.
- Additionally, this preprint (https://www.researchsquare.com/article/rs-4177311/v1) indicates that the water balance in the UTrack dataset does not appear to be closed, which leads to under- and overestimations of P and ET in either tracking direction. While this may be difficult to solve in the scope of this study, its implications should be discussed and made aware of. How could such uncertainties be addressed and how do they influence the results of this study?
- While the paper shows a novel approach of linking green water flows to economic values, the connection between green water and socio-economic outcomes needs more clarity.
- Green water appears to be treated similarly to blue water under the assumption that all green water flows can be used by humans and directly transferred into an economic value. But large parts of the flows probably remain inaccessible for direct human use and are rather important for indirect ecosystem services, and the stability of the carbon and hydrologic cycle.
- More clarity is needed to understand how the link between the green water flows and the socio-economic values are made. This is the novel part of this paper and would benefit from making this connection clearer. For instance, sections 3.1 and 3.2 present results which aren’t really novel but rather an exploration under a different geographical lens. Section 3.3 presents the novel results of this study and hence, by streamlining 3.1 and 3.2 space could be made to focus and expand on the connection between green water and socio-economic values in China.
Overall, this manuscript presents a significant contribution to the understanding of green water flows and their economic implications. Addressing the points mentioned above could help in refining the arguments and improving the clarity and robustness of the presented findings.
Citation: https://doi.org/10.5194/egusphere-2024-1420-RC2 -
AC2: 'Reply on RC2', Shan Sang, 15 Aug 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-1420/egusphere-2024-1420-AC2-supplement.pdf
- The use of the UTrack dataset for processing and tracking the green water flow is commendable. But, the uncertainties associated with the input precipitation data (P) in the forward-tracking process need further elaboration.
-
RC3: 'Comment on egusphere-2024-1420', Anonymous Referee #3, 05 Jul 2024
Review of the manuscript:
The interprovincial green water flow in China and its tele-connected effects on socio-economy
Comments
The present manuscript provides an emblematic example of integrating green water flows at a sub-national level in water management strategies. It expands on recent studies that highlighted the socio-economic value of green water teleconnections. The topic is suitable for publication and of interest to the readership of EGUsphere.
I would recommend the publication of this paper after major revisions. In the following, there are some comments that the authors may want to consider when revising their manuscript. These revisions should enhance the manuscript's clarity and depth.
Specific comments:
Abstract:
Lines 15-16: Pay attention to verb consistency for better clarity and flow.
Lines 19-21: The dataset used for the analysis is not well introduced or explained. Provide a more detailed and concise explanation of the data used.
Line 22: Include the specific value of the average self-recycling ratio.
Lines 32-35: This passage is unclear. Consider rephrasing and supporting it with specific results.
Introduction:
Line 45: Consider adding additional references for the average global terrestrial moisture recycling ratio. Rockström (2023) cites Tuinenburg (2020), they are essentially the same reference.
Lines 60-61: Clarify the period of reference for the change mentioned. Specify when the change occurred and add recent references for support.
Lines 99-103: This section is unclear. Rephrase for better clarity.
General Comments:
The Introduction could benefit from clearer explanations of certain passages. Include a characterization of China’s moisture recycling patterns, atmospheric circulation, and climatic seasonality to frame the phenomenon of moisture flows. For instance, compare the importance of moisture recycling in China to other regions globally.
Discuss the socio-economic background of the Chinese provinces involved. Highlight key socio-economic sectors and societal issues/characteristics of these regions.
Explain why analyzing green water flows at an inter-regional scale is significant, both generally and specifically for China.
Data and Methods:
General Comment: This section requires substantial improvements.
Structure: Separate the Data and Methods into two subsections. Move Figure 1 to the Methods subsection and provide detailed explanations in the caption.
Figure 1: The caption should be more detailed to enhance understanding.
Lines 127-138: Provide a more detailed explanation of the reconstruction of flows from the UTrack dataset. Clarify the processing with zonal statistics, possibly using equations or schemes for better comprehension.
Socio-economic Analysis: Since this is the core of the study, it needs a more in-depth analysis. Explain the significance of green water flows for the variables considered. How do they contribute to the services these variables represent?
Equation 1:
- Consider incorporating the areal extension of the provinces. Using population density instead of population, and expressing surface water resources per unit area, would be more appropriate. Similarly, express food production per area rather than gross food production. Use GDP per capita (GDP/P) instead of gross GDP.
- Address the role of irrigation and irrigation infrastructure in food production to avoid overestimating the contribution of green water flows. Differentiating between irrigated and rainfed productivity could be insightful.
- Include units of measure.
Equations 2 and 3:
The focus shifts to the consumption patterns of each province. However, Equation 1 deals with food production, which does not equate to food consumption. Food production in one province might be exported elsewhere. Clarify whether the study focuses on production, consumption, or both, and how these dynamics are analyzed.
General comment: Consider revising Equations 1,2 and 3 to enhance the rigour of the analysis.
Results:
Section 3.1:
Figure 2: The figure has great potential but needs improvements.
- Increase its size for better readability of numbers and histograms.
- Clarify the label of the right bar in the figure, caption, and text. Consider rephrasing for better understanding.
Lines 195-237: The discussion on PRR, DPR, and DSR contains a lot of information that is difficult to visualize. Consider creating a figure to represent these results to help the discussion of socio-economic implications.
Line 214: Provide a definition of westerly winds for a general audience. Also, it is the first time in the manuscript that atmospheric circulation is considered explicitly (see comment about the Introduction)
Section 3.2:
Suggest swapping the order with Section 3.1. The geographic visualization of flows in Section 3.2 aids in understanding the results presented in Section 3.1.
Section 3.3:
This section is well-written and interesting. However, given its significance to the analysis, consider expanding and providing more in-depth discussion.
Discussion:
Overall, this section is well-structured and written, but improvements are needed:
- Enlarge Figure 5 for greater clarity.
- Provide a deeper discussion on the uncertainty of tracked precipitation at the provincial level.
- Lines 429-431: The sentence “Our attempt... [..]” is redundant here and would be more appropriate at the end of the discussion.
General Comments for Discussion and Conclusions:
- Include a more in-depth description of the limitations of the socio-economic analysis to add value to these sections and the overall study.
- Discuss potential improvements for this type of socio-economic analysis.
- Since this study is presented as a starting example of integrating green water teleconnections into water management strategies for socio-economic applications, it would be beneficial to elaborate on additional steps needed to achieve this goal.
- Consider discussing other variables that could enhance the analysis of socio-economic implications.
Supplementary Figures and Tables are not cited, and thus integrated in the text. Please integrate them in the main text.
-
AC3: 'Reply on RC3', Shan Sang, 15 Aug 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-1420/egusphere-2024-1420-AC3-supplement.pdf
- AC4: 'Reply on AC3', Shan Sang, 17 Aug 2024
Status: closed
-
RC1: 'Comment on egusphere-2024-1420', Anonymous Referee #1, 19 Jun 2024
Sang et al. studied the interprovincial connections of green water. They quantified this by calculate the precipitation of each province from the green water inside or outside the province. The work is based on the data generated from a previous particle tracking work. Authors connect the results with social-economic effects, which is very interesting and novel. The structure and writing of the paper are clear. However, I have some thoughts as follows:
- I don’t think authors have clear enough introduction about how they connect the green water with the social-economic value. The introduction is in lines 140-175, but not clear. There are even no dimensions of the variables, and it is hard to know the relationship between different variables in the equations.
- It looks like authors assume linear relationships between water and all the social-economic indices. I am not quite sure if this is rigorous. For example, whether the food productivity has the positive, linear relationship with water? Similar question to other social-economic indices.
- For the sections of sources and sinks of green water (sections 3.1 and 3.2), it is hard to say they are really novel as it looks like some known results with a new wrapper. You are talking about the evapotranspiration circulation by adding the ‘interprovincial’ concept.
- Authors said the data are high quality data from previous studies. I think a bit more introduction is necessary.
- It is a long-term dataset. So why not analyze the temporal variations of these teleconnections? I think this is more important to audience. The average state is also important, but they are the natural pattern which are caused by the long-term climatic conditions. We should know this basic pattern, but we cannot change it much. The more important thing is the temporal variations which represent the variations caused by some interannual variations of natural conditions or by man-made climate change. This is important to inform the future social-economic development, e.g., if such variations are good or bad and if we need actions to control or facilitate such variations.
I suggest major revision of this manuscript.
Citation: https://doi.org/10.5194/egusphere-2024-1420-RC1 -
AC1: 'Reply on RC1', Shan Sang, 15 Aug 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-1420/egusphere-2024-1420-AC1-supplement.pdf
-
RC2: 'Comment on egusphere-2024-1420', Anonymous Referee #2, 03 Jul 2024
The paper presents a novel and insightful approach to connect green water flows to their economic value across different provinces in China. The manuscript is well-structured and written. However, there are a few points that could be clarified and improved to enhance the overall impact and clarity of the study.
- The use of the UTrack dataset for processing and tracking the green water flow is commendable. But, the uncertainties associated with the input precipitation data (P) in the forward-tracking process need further elaboration.
- It would be good to include the processing scripts for the UTrack dataset and a clearer explanation how you got from the dataset to the data that is used in the already included Python notebook.
- Additionally, this preprint (https://www.researchsquare.com/article/rs-4177311/v1) indicates that the water balance in the UTrack dataset does not appear to be closed, which leads to under- and overestimations of P and ET in either tracking direction. While this may be difficult to solve in the scope of this study, its implications should be discussed and made aware of. How could such uncertainties be addressed and how do they influence the results of this study?
- While the paper shows a novel approach of linking green water flows to economic values, the connection between green water and socio-economic outcomes needs more clarity.
- Green water appears to be treated similarly to blue water under the assumption that all green water flows can be used by humans and directly transferred into an economic value. But large parts of the flows probably remain inaccessible for direct human use and are rather important for indirect ecosystem services, and the stability of the carbon and hydrologic cycle.
- More clarity is needed to understand how the link between the green water flows and the socio-economic values are made. This is the novel part of this paper and would benefit from making this connection clearer. For instance, sections 3.1 and 3.2 present results which aren’t really novel but rather an exploration under a different geographical lens. Section 3.3 presents the novel results of this study and hence, by streamlining 3.1 and 3.2 space could be made to focus and expand on the connection between green water and socio-economic values in China.
Overall, this manuscript presents a significant contribution to the understanding of green water flows and their economic implications. Addressing the points mentioned above could help in refining the arguments and improving the clarity and robustness of the presented findings.
Citation: https://doi.org/10.5194/egusphere-2024-1420-RC2 -
AC2: 'Reply on RC2', Shan Sang, 15 Aug 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-1420/egusphere-2024-1420-AC2-supplement.pdf
- The use of the UTrack dataset for processing and tracking the green water flow is commendable. But, the uncertainties associated with the input precipitation data (P) in the forward-tracking process need further elaboration.
-
RC3: 'Comment on egusphere-2024-1420', Anonymous Referee #3, 05 Jul 2024
Review of the manuscript:
The interprovincial green water flow in China and its tele-connected effects on socio-economy
Comments
The present manuscript provides an emblematic example of integrating green water flows at a sub-national level in water management strategies. It expands on recent studies that highlighted the socio-economic value of green water teleconnections. The topic is suitable for publication and of interest to the readership of EGUsphere.
I would recommend the publication of this paper after major revisions. In the following, there are some comments that the authors may want to consider when revising their manuscript. These revisions should enhance the manuscript's clarity and depth.
Specific comments:
Abstract:
Lines 15-16: Pay attention to verb consistency for better clarity and flow.
Lines 19-21: The dataset used for the analysis is not well introduced or explained. Provide a more detailed and concise explanation of the data used.
Line 22: Include the specific value of the average self-recycling ratio.
Lines 32-35: This passage is unclear. Consider rephrasing and supporting it with specific results.
Introduction:
Line 45: Consider adding additional references for the average global terrestrial moisture recycling ratio. Rockström (2023) cites Tuinenburg (2020), they are essentially the same reference.
Lines 60-61: Clarify the period of reference for the change mentioned. Specify when the change occurred and add recent references for support.
Lines 99-103: This section is unclear. Rephrase for better clarity.
General Comments:
The Introduction could benefit from clearer explanations of certain passages. Include a characterization of China’s moisture recycling patterns, atmospheric circulation, and climatic seasonality to frame the phenomenon of moisture flows. For instance, compare the importance of moisture recycling in China to other regions globally.
Discuss the socio-economic background of the Chinese provinces involved. Highlight key socio-economic sectors and societal issues/characteristics of these regions.
Explain why analyzing green water flows at an inter-regional scale is significant, both generally and specifically for China.
Data and Methods:
General Comment: This section requires substantial improvements.
Structure: Separate the Data and Methods into two subsections. Move Figure 1 to the Methods subsection and provide detailed explanations in the caption.
Figure 1: The caption should be more detailed to enhance understanding.
Lines 127-138: Provide a more detailed explanation of the reconstruction of flows from the UTrack dataset. Clarify the processing with zonal statistics, possibly using equations or schemes for better comprehension.
Socio-economic Analysis: Since this is the core of the study, it needs a more in-depth analysis. Explain the significance of green water flows for the variables considered. How do they contribute to the services these variables represent?
Equation 1:
- Consider incorporating the areal extension of the provinces. Using population density instead of population, and expressing surface water resources per unit area, would be more appropriate. Similarly, express food production per area rather than gross food production. Use GDP per capita (GDP/P) instead of gross GDP.
- Address the role of irrigation and irrigation infrastructure in food production to avoid overestimating the contribution of green water flows. Differentiating between irrigated and rainfed productivity could be insightful.
- Include units of measure.
Equations 2 and 3:
The focus shifts to the consumption patterns of each province. However, Equation 1 deals with food production, which does not equate to food consumption. Food production in one province might be exported elsewhere. Clarify whether the study focuses on production, consumption, or both, and how these dynamics are analyzed.
General comment: Consider revising Equations 1,2 and 3 to enhance the rigour of the analysis.
Results:
Section 3.1:
Figure 2: The figure has great potential but needs improvements.
- Increase its size for better readability of numbers and histograms.
- Clarify the label of the right bar in the figure, caption, and text. Consider rephrasing for better understanding.
Lines 195-237: The discussion on PRR, DPR, and DSR contains a lot of information that is difficult to visualize. Consider creating a figure to represent these results to help the discussion of socio-economic implications.
Line 214: Provide a definition of westerly winds for a general audience. Also, it is the first time in the manuscript that atmospheric circulation is considered explicitly (see comment about the Introduction)
Section 3.2:
Suggest swapping the order with Section 3.1. The geographic visualization of flows in Section 3.2 aids in understanding the results presented in Section 3.1.
Section 3.3:
This section is well-written and interesting. However, given its significance to the analysis, consider expanding and providing more in-depth discussion.
Discussion:
Overall, this section is well-structured and written, but improvements are needed:
- Enlarge Figure 5 for greater clarity.
- Provide a deeper discussion on the uncertainty of tracked precipitation at the provincial level.
- Lines 429-431: The sentence “Our attempt... [..]” is redundant here and would be more appropriate at the end of the discussion.
General Comments for Discussion and Conclusions:
- Include a more in-depth description of the limitations of the socio-economic analysis to add value to these sections and the overall study.
- Discuss potential improvements for this type of socio-economic analysis.
- Since this study is presented as a starting example of integrating green water teleconnections into water management strategies for socio-economic applications, it would be beneficial to elaborate on additional steps needed to achieve this goal.
- Consider discussing other variables that could enhance the analysis of socio-economic implications.
Supplementary Figures and Tables are not cited, and thus integrated in the text. Please integrate them in the main text.
-
AC3: 'Reply on RC3', Shan Sang, 15 Aug 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-1420/egusphere-2024-1420-AC3-supplement.pdf
- AC4: 'Reply on AC3', Shan Sang, 17 Aug 2024
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