A Refined Four-Stream Radiative Transfer Model for Row-Planted Crops
Round 1
Reviewer 1 Report
The authors presented a refined radiative transfer model for row planted crops. They took row space into consideration for a more accurate estimation. The result was compared with RGM model. The MFS model, which is proposed in this paper, is obviously faster than the RGM model because RGM is a numerical model and MFS is not. Besides the comparison with computer simulated data, this work also tried to validate its work with in-situ experiment data when viewing zenith angle is 60 degree, and the result looks good. I recommend this work to be published, bu need some revises, as commented below.
Major comments:
- Line 542: In Table 3, the average difference is roughly large at first two stages, and is smaller at last two stages. Does it mean the proposed MFS model does not perform well when space between crop rows is relatively large?
- Line 548: For the validation using in-situ data, I’d like to see more comparison at varied viewing zenith angles. The in-situ data is collected from +60 degree to -60 degree, and it will be good to show another one or two sets of comparison.
Minor comments:
- Line 162: ‘ef’ is missing in Fig.1(a).
- Line 190: In Eq(16), A_2 should be revised for consistent font as other symbols.
- Line 460: For Fig. 4, 6, 8, and 10, I recommend the legend to be changed to stage_rv1,2,3 and cv, which is more clear than LAI value.
Author Response
Reviewer #1
The authors presented a refined radiative transfer model for row planted crops. They took row space into consideration for a more accurate estimation. The result was compared with RGM model. The MFS model, which is proposed in this paper, is obviously faster than the RGM model because RGM is a numerical model and MFS is not. Besides the comparison with computer simulated data, this work also tried to validate its work with in-situ experiment data when viewing zenith angle is 60 degree, and the result looks good. I recommend this work to be published, but need some revises, as commented below.
Major comments:
Line 542: In Table 3, the average difference is roughly large at first two stages, and is smaller at last two stages. Does it mean the proposed MFS model does not perform well when space between crop rows is relatively large?
Response: Yes, the reviewer is correct. When the fraction of the distance of between-rows was large, the systematic deviation occurred between the two models, e.g., the maximum absolute value for the average difference in Stage_rv1 was 22.64% in Table 1, and the maximum absolute value for the average difference in Stage_rv2 was 13.76%. The primary reason is that the two models have different algorithms to calculate the DRF of the soil of between-rows. The MFS uses a one-dimensional integral equation (Eq. (E-1) Supplementary Material E), which calculates the isotropic DRF of the soil of between-rows. The RGM is a three-dimensional computer model, which calculates the anisotropic DRF of the soil of between-rows (e.g., the brown squares shown in Fig. 2 are approximated as an anisotropic soil). Therefore, as the distance of between-rows increases, the area fraction of soil increases, and the difference in DRFs become more obvious. We have discussed and clarified this difference in our revised manuscript (see page 25, lines 639-648).
Line 548: For the validation using in-situ data, I’d like to see more comparison at varied viewing zenith angles. The in-situ data is collected from +60 degree to -60 degree, and it will be good to show another one or two sets of comparison.
Response: Agreed. We have added another set of comparisons from +50 degree and -50 degree as suggested by the reviewer (see page 23, lines 573-577). The statistics of this comparison have also been added in Table 4.
Minor comments:
Line 162: ‘ef’ is missing in Fig.1(a).
Response: Indeed. We have added ‘ef’ in Fig. 1(a). Please refer to page 4, line 160.
Line 190: In Eq(16), A_2 should be revised for consistent font as other symbols.
Response: Implemented. Please see page 5, line 201.
Line 460: For Fig. 4, 6, 8, and 10, I recommend the legend to be changed to stage_rv1,2,3 and cv, which is more clear than LAI value.
Response: Agreed. We have changed the legend as suggested by the reviewer. Please refer to page 14, Line 471; page 16, line 492; page18, line 522; and page 20, line532
Author Response File: 
Author Response.docx
Reviewer 2 Report
I suggest to publish the manuscript without any negative comments.
Comments for author File: 
Comments.pdf
Author Response
Reviewer #2
I suggest to publish the manuscript without any negative comments.
Response: Thank you for your support.
Reviewer 3 Report
In general, the manuscript is well written, with a clear and simple language. Figures and tables are appropriate and illustrate very well the most relevant results of the study. However, I have a couple considerations before the paper can be accepted for publication: 1) The Introduction must be greatly improved by adding newer references; and 2) The authors must rewrite the conclusions, evidencing the actual importance of the study and the most important findings.
Author Response
Reviewer #3
In general, the manuscript is well written, with a clear and simple language. Figures and tables are appropriate and illustrate very well the most relevant results of the study. However, I have a couple considerations before the paper can be accepted for publication: 1) The Introduction must be greatly improved by adding newer references; and 2) The authors must rewrite the conclusions, evidencing the actual importance of the study and the most important findings.
Response: Agreed. We have improved the Introduction section by adding newer references (see page 26, lines 711-712; page 27, lines 737-760; pages 28, lines 727-768; page 28, 792-794). Moreover, we have also rewritten the Conclusion section and further emphasized the importance and the main findings of our study as suggested by the reviewer (see pages 25-26, lines 673-684).
Author Response File: Author Response.docx
