Real-Time Measurement of Atmospheric CO2, CH4 and N2O above Rice Fields Based on Laser Heterodyne Radiometers (LHR)
, Yue Li 1,2, Guangyu Bo 2, Fengjiao Shen 3, Xiaoming Gao 1,2, Jian Zhang 4,5,* and Tu Tan 2,*Round 1
Reviewer 1 Report
This paper is purely a work report in its current state. However, scientific article elements can be added to make it more sound and informative. For instance, comparison with the conventional method and techniques. What's the prospect of LHR? Pros and cons? These issues are of sufficient interest and can be added to the discussion section.
Comment points:
Line 25 “The LHRs have strong application prospects for monitoring emissions from agricultural fields.” Is this a key implication of your work? Need more comparisons to prove your point.
Line 59-66; Line 72-77 Three techniques you mentioned: chamber gas chromatography, eddy covariance technique, and Laser Heterodyne Radiometers (LHR).
It seems like the LHR succeeded in the gas chromatography and the eddy covariance technique. Will LHR supplant them? What’s the future trend?
Line 82 Specify LO
Line 87 Specify DFB
Please check all your abbreviations and follow the general using rule. “As a general rule, all non-standard abbreviations/acronyms should be written out in full on first use (in both the abstract and the paper itself) and followed by the abbreviated form in parentheses”
Figure 4 Text is too small, and difficult to read
Equations 1,2,3 Try to give some physical explanation to the equations. What is the physical meaning of the mathematical equation? Readers want to understand the concept clearly.
Figure 5, 6,7. Please strive to make fairly good graphs. If the graph has "error bars," you should say in the caption whether they're a 95% confidence interval, standard error, or standard deviation, ...
Author Response
Re: Agronomy 2130492
Dear editor/reviewers:
Thank you for your letter and the reviewers’ comments concerning our manuscript entitled “Real-time Measurement of Atmospheric CO2, CH4 and N2O above Rice Fields based on Laser Heterodyne Radiometers (LHR)” (ID: agronomy-2130492). Your comments and suggestion are valuable and very helpful. We have read through all your comments carefully and made corrections accordingly. We revised the manuscript based on your inputs (in blue). Here below are our point-by-point responses (in black).
We thank you for allowing us to resubmit a revised version of the manuscript and we highly appreciate your time and consideration.
Best Regards,
.
Jun Li, Zhengyue Xue and Jian on behalf of all authors
Reviewer #1:
This paper is purely a work report in its current state. However, scientific article elements can be added to make it more sound and informative. For instance, comparison with the conventional method and techniques. What's the prospect of LHR? Pros and cons? These issues are of sufficient interest and can be added to the discussion section.
Response: Thank you very much for your commons and suggestions. Related content have been added to the discussion section as you suggested. Although the observation purposes of traditional methods and techniques are not consistent with what we are examined in this paper, the prospects of advantages and disadvantages of LHR are also worthwhile to be discussed.
Comment points:
Line 25 “The LHRs have strong application prospects for monitoring emissions from agricultural fields.” Is this a key implication of your work? Need more comparisons to prove your point.
Response: We are grateful for the suggestions. LHRs have the advantages of portability and high precision, which can accurately measure the concentration of greenhouse gases in a certain area. It has a strong application prospect in monitoring farmland emissions, which was summarized in our report. The previous measurement results [ref 17, 20] and the corresponding measurement results in this paper would effectively prove that LHRs have strong application prospects for monitoring emissions from agricultural fields. Other observation methods such as satellite observations, ground-based Fourier Transform Spectrometers could not obtain real-time gas concentrations over paddy fields, this monitoring technique for emissions detection is ineffective.
Line 59-66; Line 72-77 Three techniques you mentioned: chamber gas chromatography, eddy covariance technique, and Laser Heterodyne Radiometers (LHR). It seems like the LHR succeeded in the gas chromatography and the eddy covariance technique. Will LHR supplant them? What’s the future trend?
Response: Laser Heterodyne Radiometers (LHR) will not supplant chamber gas chromatography, eddy covariance technique. Chamber gas chromatography and eddy covariance technique are used for real-time all-weather surface flux emission measurements. LHRs and developed inversion algorithms are mainly used in the Earth 's atmospheric column abundance measurement, it can be extended to a larger area of greenhouse gas content change monitoring. In the future, three measurement methods combined to build a three-dimensional large-scale real-time emission monitoring system would be considered.
Line 82 Specify LO Line 87 Specify DFB. Please check all your abbreviations and follow the general using rule. “As a general rule, all non-standard abbreviations/acronyms should be written out in full on first use (in both the abstract and the paper itself) and followed by the abbreviated form in parentheses”
Response: Thank you for your careful inspection. We agree with the comment and re-write the contents in the revised manuscript.
Figure 4 Text is too small, and difficult to read
Response: We agree with the comment and modify the figure 4 in the revised manuscript.
Equations 1,2,3 Try to give some physical explanation to the equations. What is the physical meaning of the mathematical equation? Readers want to understand the concept clearly.
Response: LHRs belong to the field of remote sensing detection. We construct a forward model and solve the equation by inversion algorithm to obtain the gas column abundance over the final farmland. Equation 1: the forward model we constructed, which represents the process of solar radiation absorption by gas. Equation 2 is the method we use to solve the equation. The total column abundance above paddy field is calculated by Equation 3.
Figure 5, 6,7. Please strive to make fairly good graphs. If the graph has "error bars," you should say in the caption whether they're a 95% confidence interval, standard error, or standard deviation, ...
Response: Thank you for the common. We agree with the comment and re-write the figure caption in the revised manuscript.
Reviewer 2 Report
Interesting paper that addresses current issues not only in the open field but above all in the livestock sector. There is no specific statistical validation of the results, the observed results are assumed to be valid, the importance of the sampling points in the atmosphere should be investigated and her height from the soil surface, the advantages and limits that this study can determine for the crop can be investigated, especially if there are relationships between gas emission and yield and qualitative aspects. The conclusions have to be completely redone as they must not be a restatement of the results but rather an opportunity to highlight advantages, limitations, critical issues of future developments or a starting point for application possibilities of the study
Author Response
Re: Agronomy 2130492
Dear editor/reviewers:
Thank you for your letter and the reviewers’ comments concerning our manuscript entitled “Real-time Measurement of Atmospheric CO2, CH4 and N2O above Rice Fields based on Laser Heterodyne Radiometers (LHR)” (ID: agronomy-2130492). Your comments and suggestion are valuable and very helpful. We have read through all your comments carefully and made corrections accordingly. We revised the manuscript based on your inputs (in blue). Here below are our point-by-point responses (in black).
We thank you for allowing us to resubmit a revised version of the manuscript and we highly appreciate your time and consideration.
Best Regards,
Jun Li, Zhengyue Xue and Jian on behalf of all authors
Reviewer #2:
Interesting paper that addresses current issues not only in the open field but above all in the livestock sector. There is no specific statistical validation of the results, the observed results are assumed to be valid, the importance of the sampling points in the atmosphere should be investigated and her height from the soil surface, the advantages and limits that this study can determine for the crop can be investigated, especially if there are relationships between gas emission and yield and qualitative aspects. The conclusions have to be completely redone as they must not be a restatement of the results but rather an opportunity to highlight advantages, limitations, critical issues of future developments or a starting point for application possibilities of the study
Response: We are grateful for the suggestion and refined discussion. We rewrite our conclusions in the revised manuscript. In the discussion section, we add the advantages, limitations, key issues for future development of the starting point for research and application possibilities of heterodyne radiometers. In addition, our main research content is the relationship between greenhouse gas concentration changes in paddy fields and crop planting status. Unlike gas chamber gas chromatography and vorticity correlation techniques, we measured not the emission flux of surface crops, but also the change of greenhouse gas column abundance from surface to stratosphere in a large area. Therefore, it is difficult to determine the relationship between gas emission and yield and quality. In future work, we will focus on the combined use of multiple technologies, build a three-dimensional observation network to monitor emissions in real time, and further determine the relationship between gas emissions and yield and quality.
