Distinct Contributions of Climate Change and Anthropogenic Activities to Evapotranspiration and Gross Primary Production Variations over Mainland China
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis manuscript used an ecological model to show that evapotranspiration and gross primary productivity have increased in recent decades. The authors show that ecological restoration policies have influenced these changes in a favorable way. In general, this is a very polished manuscript. I have only a few recommendations...
- Introduction: Be explicit in what this study does to improve on the existing state of knowledge. It is unclear how this study will add to the literature.
- Provide a more detailed explanation of how ridge regression works and why it is the preferred method for the attribution.
- Why did the model perform so poorly for GPP in DHS? There is essentially no skill in that relationship.
Author Response
Responses
We have labelled the revised section as red in revised manuscript.
This manuscript used an ecological model to show that evapotranspiration and gross primary productivity have increased in recent decades. The authors show that ecological restoration policies have influenced these changes in a favorable way. In general, this is a very polished manuscript. I have only a few recommendations...
- Introduction: Be explicit in what this study does to improve on the existing state of knowledge. It is unclear how this study will add to the literature.
Response: we have revised in line 5 in Abstract section and in lines 9-14 in paragraph 3 in page 2.
- Provide a more detailed explanation of how ridge regression works and why it is the preferred method for the attribution.
Response: we have revised in the last paragraph in page 7 and first paragraph in page 8.
- Why did the model perform so poorly for GPP in DHS? There is essentially no skill in that relationship.
Response: There is a deviation in the extraction of the occupying position in the original manuscript. We have revised in section 3.1 and figure 2 in page 8 and 9.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsEvapotranspiration is an important component of the terrestrial water cycle and an important way to study regional water resources distribution and flood and drought disasters. This manuscript explores the impact and contribution of climate change and human activities on evapotranspiration in different climate regions in mainland China based on remote sensing satellite data. This is of great significance for studying the spatiotemporal evolution characteristics of regional evapotranspiration. The manuscript is rich in content, rigorous in logic, and applicable in method, but there are still some details. The corresponding details have been listed below. It is recommended that the manuscript be published after minor revision.
An introduction to the vegetation, climate and hydrological conditions of the study area should be added to the manuscript.
L108, “Model data” should be changed to “Data”.
Figure 5: The subfigures need to be described, and the legends in the subfigures are too small to be seen. Suggest changes.
Figure 6: The subfigures need to be described.
Conclusion: It is recommended to increase the line of defense for future work.
Author Response
Responses
We have labelled the revised section as red in revised manuscript.
Evapotranspiration is an important component of the terrestrial water cycle and an important way to study regional water resources distribution and flood and drought disasters. This manuscript explores the impact and contribution of climate change and human activities on evapotranspiration in different climate regions in mainland China based on remote sensing satellite data. This is of great significance for studying the spatiotemporal evolution characteristics of regional evapotranspiration. The manuscript is rich in content, rigorous in logic, and applicable in method, but there are still some details. The corresponding details have been listed below. It is recommended that the manuscript be published after minor revision.
- An introduction to the vegetation, climate and hydrological conditions of the study area should be added to the manuscript.
Response: we have revised in section 2.1 in page 3.
- L108, “Model data” should be changed to “Data”.
Response: we have revised in section 2.2 in page 3.
- Figure 5: The subfigures need to be described, and the legends in the subfigures are too small to be seen. Suggest changes.
Response: we have revised in Figure 5 and Figure 5S.
- Figure 6: The subfigures need to be described.
Response: we have revised in Figure 6 in page 13.
- Conclusion: It is recommended to increase the line of defense for future work.
Response: we have revised in first paragraph in page 20.
Author Response File: Author Response.docx
Reviewer 3 Report
Comments and Suggestions for AuthorsThe manuscript estimated ET and GPP between 1999 and 2018 over China, and quantitatively analyzed the contributions of climatic factors and anthropogenic activities to ET and GPP variations. The results seem reasonable. However, there are still some questions and major revisions needed.
(1) The net radiation Rn was used in the calculation of IPAR (Equation 13), which is unreasonable because the net radiation includes longwave radiation, and longwave radiation is not related to PAR. Also, what is the parameter of a in Equation 13?
(2) The observation data of 7 flux towers were used in the parameter optimization, but there was no DNF and DBF in the vegetation types of these 7 stations, how to determine the parameters of these two vegetation types.
(3) The manuscript says that the contributions of climatic factors and anthropogenic on ET and GPP are calculated using ridge regression, but the method is not described in detail, and it needs to be added how to determine the contribution of different factors.
(4) What are the possible reasons for the poor estimation of the GPP at DHS station in Figure 2?
(5) The manuscript does not introduce how the LAIH and LAIH trend values are determined, and needs to be added. Figure 6c shows that there is trend value of LAI and LAIH each year, how is it calculated?
(6) Line 355, “28.50% in SubT” should be “47.55% in SubT” according to Table 2.
(7) The English writing needed improved.
Comments on the Quality of English LanguageThe English writing needed improved.
Author Response
Responses
We have labelled the revised section as red in revised manuscript.
The manuscript estimated ET and GPP between 1999 and 2018 over China, and quantitatively analyzed the contributions of climatic factors and anthropogenic activities to ET and GPP variations. The results seem reasonable. However, there are still some questions and major revisions needed.
- The net radiation Rn was used in the calculation of IPAR (Equation 13), which is unreasonable because the net radiation includes longwave radiation, and longwave radiation is not related to PAR. Also, what is the parameter of a in Equation 13?
Response: we have revised in equation 14 and in the fourth paragraph in page 6.
- The observation data of 7 flux towers were used in the parameter optimization, but there was no DNF and DBF in the vegetation types of these 7 stations, how to determine the parameters of these two vegetation types.
Response: The parameters about DNF and DBF vegetation types are respectively referenced parameters calibrated in ENF and EBF vegetation types and total ET and GPP in the precious literatures.
- The manuscript says that the contributions of climatic factors and anthropogenic on ET and GPP are calculated using ridge regression, but the method is not described in detail, and it needs to be added how to determine the contribution of different factors.
Response: we have revised in section 2.3.3 in page 7 and 8.
- What are the possible reasons for the poor estimation of the GPP at DHS station in Figure 2?
Response: There is a deviation in the extraction of the occupying position in the original manuscript. We have revised in section 3.1 and figure 2 in page 8 and 9.
- The manuscript does not introduce how the LAIH and LAIH trend values are determined, and needs to be added. Figure 6c shows that there is trend value of LAI and LAIH each year, how is it calculated?
Response: we have revised in the second paragraph in section 2.3.3 in page 7.
- Line 355, “28.50% in SubT” should be “47.55% in SubT” according to Table 2.
Response: we have revised in the second paragraph in page 14.
- The English writing needed improved.
Response: we have revised the errors and details in the whole manuscript.
Author Response File: Author Response.docx
Reviewer 4 Report
Comments and Suggestions for AuthorsThe article deals with a very important topic for understanding the anthropogenic impact on the exchange of Carbon and water between the surface and the atmosphere. The article is written in a clear language, easy to follow. However, while the methods for obtaining ET and GPP are well detailed, the method to identify vegetation changes disturbed by climate factors and anthropogenic activities, the residual trend method, lacks clarity. Specifically, the article should provide more information on how LAI components are obtained (LAIC induced by climate, LAIH disturbed by human activities, and a negligible residual). A revision to clarify this issue is needed.
Specific comments:
Line 109: Here ‘Meteorological data’ are being described instead Meteorological factors.
Line 159: The number of equations are from Leuning et al, 2008? please clarify
Eq. 4 - How Rn is calculated? only solar radiation is the input meteorological data
Line 190: review andεin
Section 2.2.2 – in this section is necessary to describe what optimization method was used
Section 2.3.2 The residual trend method (Radda et al.,2021) must be better described in section 2.2.3. It is the main method used in this paper and must be clearly described.
Line 305 – 315: review Figure number
Line 305 – 306: review subscript kg-1
Line 194 and Line 368 – Table 2
The variable abbreviations in Table 2 – Line 368 must be described in the text
Figure 5 - please clarify what are the legends for left, central and right panel
Line 438: is SW or SR?
Author Response
Responses
We have labelled the revised section as red in revised manuscript.
The article deals with a very important topic for understanding the anthropogenic impact on the exchange of Carbon and water between the surface and the atmosphere. The article is written in a clear language, easy to follow. However, while the methods for obtaining ET and GPP are well detailed, the method to identify vegetation changes disturbed by climate factors and anthropogenic activities, the residual trend method, lacks clarity. Specifically, the article should provide more information on how LAI components are obtained (LAIC induced by climate, LAIH disturbed by human activities, and a negligible residual). A revision to clarify this issue is needed.
Specific comments:
- Line 109: Here ‘Meteorological data’ are being described instead Meteorological factors.
Response: we have revised in section 2.2 in page 3.
- Line 159: The number of equations are from Leuning et al, 2008? please clarify
Response: we have revised in last paragraph in page 4 and first paragraph in page 5.
- Eq. 4 - How Rn is calculated? only solar radiation is the input meteorological data
Response: we have revised in equation 5 in page 5.
- Line 190: review and εin
Response: we have revised in the first paragraph in section 2.3.2 in page 6.
- Section 2.2.2 – in this section is necessary to describe what optimization method was used
Response: we have revised in the first paragraph in section 2.3.2 in page 6.
- Section 2.3.2 The residual trend method (Radda et al.,2021) must be better described in section 2.2.3. It is the main method used in this paper and must be clearly described.
Response: we have revised in the second paragraph in section 2.3.3 page 7.
- Line 305 – 315: review Figure number
Response: we have revised in fourth and fifth paragraphs in section 3.3.1 page 11.
- Line 305 – 306: review subscript kg-1
Response: we have revised in fourth paragraph in section 3.3.1 page 11.
- Line 194 and Line 368 – Table 2
Response: we have revised in second paragraph in page 15 and Table 2 in page 6.
- The variable abbreviations in Table 2 – Line 368 must be described in the text
Response: we have revised in the second paragraph in page 15.
- Figure 5 - please clarify what are the legends for left, central and right panel
Response: we have revised in Figure 5 in page 12 and Figure 5S in Appendix.
- Line 438: is SW or SR?
Response: SW is right in the third paragraph in page 23.
Author Response File: Author Response.docx
Reviewer 5 Report
Comments and Suggestions for Authors1) "1999 to 2018" is commonly used to denote the 20-year time span. It's a little bit confusing. Does it mean every year between 1999 and 2018? Or are only the two years 1999 and 2008 used?
2) Please clarify the parameters in line 167.
3) Please add some discussion to Figure 2 DHS_GPP (R2=0.02).
4) Figure 2. Simulated monthly ET and GPP versus EC observations from 2003-2009. GPP observations?
5) Line 283 Figure 4 (b) (e) ET and GPP?
6) Figure 5. Please indicate which column of the figure corresponds to trends, trend significance, and statistical trends.
7) Please discuss the four sub-region trends related to the policies you mentioned.
8) Please add more references to compare your results with other studies.
9) Please revise the figure descriptions. Please provide enough information for the reader to understand the figure without referring to the main text.
Comments on the Quality of English Language
The paper is generally well-written but could benefit from some revisions to enhance clarity and flow. Consider a thorough proofreading to identify and correct minor grammatical and typographical errors.
Author Response
Responses
We have labelled the revised section as red in revised manuscript.
- "1999 to 2018" is commonly used to denote the 20-year time span. It's a little bit confusing. Does it mean every year between 1999 and 2018? Or are only the two years 1999 and 2008 used?
Response: it means every year.
- Please clarify the parameters in line 167.
Response: we have revised in second paragraph in page 5.
- Please add some discussion to Figure 2 DHS_GPP (R2=0.02).
Response: There is a deviation in the extraction of the occupying position in the original manuscript. We have revised in section 3.1 and figure 2 in page 8 and 9.
- Figure 2. Simulated monthly ET and GPP versus EC observations from 2003-2009. GPP observations?
Response: yes. GPP values are observations.
- Line 283 Figure 4 (b) (e) ET and GPP?
Response: we have revised in figure 4 in page 11.
- Figure 5. Please indicate which column of the figure corresponds to trends, trend significance, and statistical trends.
Response: we have revised in Figure 5 in page 12 and Figure 5S in Appendix.
- Please discuss the four sub-region trends related to the policies you mentioned.
Response: we have revised in the second paragraph in page 13.
- Please add more references to compare your results with other studies.
Response: we have revised in the second paragraph in page 10.
- Please revise the figure descriptions. Please provide enough information for the reader to understand the figure without referring to the main text.
Response: we have revised all the figures in the whole manuscript.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsThe numbers of the formulas are not in order.
