Determination of Microtopography of Low-Relief Tidal Freshwater Forested Wetlands Using LiDAR
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsMicrotopography of tidal freshwater forested wetlands impacts biogeochemical processes affecting the carbon and nitrogen dynamics,ecological parameters,and habitat diversity. this paper assess the high-resolution fine-scale microtopographic features of a TFFW with terrestrial LiDAR and aerial LiDAR to test a method appropriate to quantify microto- pography in low-relief forested wetlands.This study shows that a combination of water level and percentile elevation thresholding can correctly characterize the microtopography of low-relief topography, and the microtopography charac terization method described here provides a basis for advanced applications and scaling mechanistic models. This research has certain significance for microtopography of low-relief tidal freshwater forested wetlands. Therefore, I recommend accepting this manuscript for publication after some concerns being clarified with revisions.
1. Lines 135-136, with only six control points selected, are they fewer and will they meet the accuracy requirements of the experiment?
2. The size of the scale should be indicated in Figure 3.
3. In microtopographic analysis, the horizontal resolution threshold should be determined according to local conditions and should be related to the vertical accuracy, especially in the case of microtopography, where the relationship and the interaction between the two may be closer. This can be discussed in more depth.
4. The discussion section could expand on the detailed and extensive description.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsComments to text:
1. Page 1, line 10: Correct the word order: …objectives of this study were: 1) to characterize an assess...
2. Page 1, line 20: Double space between words: … planet. Freshwater tidal wetlands…
3. Page 2, line 54: Please specify the resolution range of DEM that you (or according to the literature) consider too coarse (low resolution).
4. Page 2, line 56: Same as above: what range is “very high-resolution DEM”? 0.01m? 0.001m?
5. Page 2, line 70: Suggestion to improve the verb: Moore et al. [16] used structure from motion…
7. Page 2, line 81: Add a comma: Therefore, the objectives…
8. Page 2, line 81: Correct the word order, same as in abstract: …objectives of this study were: 1) to characterize an assess...
9. Page 2, line 85: I think a more correct form is “focused” with one “s”.
10. Page 3, line 99: Double space between words: … estuary. The study site…
11. Page 3, line 101: Double space between words: … [21]. The data acquisition…
12. Page 3, line 104: What does it mean? A much more frequently given parameter of data source is the point cloud density, expressed in points per square meter. And also declared accuracy.
13. Page 3, figure 1: The figure is difficult to read. The general map should show the location of the study area on the US border / South Carolina border – this map should be smaller than the one showing the study area - its border should be marked. The map does not contain a legend (e.g. the elevation range shown on the center map). Elements of the figure can be numbered, e.g. a, b, c. You can also show the study area in the Francis Marion National Forest and the surroundings as it is now, but the applied base does not violate copyright (Google maps / OSM)?
14. Page 3, line 107-114. What criteria or methods of evaluation were used to assess the necessary size of the study area? Why is 4330 m2 appropriate, and 2000 m2 would not be enough or 5000 m2 would be not more useful? The text contains only a comparison with previously published studies and reasons for selecting the study area, without reference to its size. I suggest deleting the sentence regarding the assessment of the area.
15. Page 4, line 119-120: It is unnecessary to repeat the information from page 3 (line 101-102) about the time of data acquisition and its reasons (leaf off season etc.). It’s enough to provide this information once.
16. Page 5, figure 2: I don't quite understand the point of including Figure 2. Maybe it would be better to show the actual layout of the location where the ground scanner was located, compared to the boundaries of the study area? Then you can also show the location of the ground control points.
17. Page 6, line 154: Then, the georeferenced point cloud was subsampled and exported for further analysis.
18. Page 8, line 188-196. This paragraph is still an element of the methods description, it should be placed as chapter 3.5. – “Aerial and terrestrial point clouds comparison”. Chapter 4. could be simply called “Results”.
19. Page 8, line 201-202: The last sentence of a paragraph does not end with a dot.
20. Page 8, figure 5: I don’t understand the title of the figure. Maybe like this: “Terrestrial-based (A) and Aerial-based (B) LiDAR DEM of study area”. The highest hypsometric scale values ​​in the legend should be placed at the top.
21. Page 8, line 207-209: The t-test statistic should be reported, as well as why the probability was estimated at 0.01 (usually 0.05 in the natural sciences). It may also be useful to calculate the Cohen’s Kappa coefficient to measure similarity between these DEMs.
22. Page 9, figure 6: Maps A) and B) are unlabeled on the figure.
23. Page 9, line 241: The ASL abbreviation is written here with dots, while in other places it is written without them (e.g. Page 4, line 124; Page 13, line 330). The notation should be unified.
24. Page 11, line 283-284: Providing GCPs is a much more widely used method, also in Terrestrial LiDAR studies. And: “ placing GCPs on the ground” is pleonasm (placing ground control points on the ground…).
25. Page 12, line 297-298: This sentence (“Microtopography plays an important role in the ecological, biogeochemcal and hydrological functions of wetlands.”) is a summary of the context of the article (part of the abstract or introduction), not its conclusion.
26. Page 12, line 307-310: This sentence is not the conclusion of your article - you did not make a comparison between devices with a bathymetric / green laser and a ground, infrared one. You can transform this sentence as a hint for further methodological research.
27. Page 13, line 330: The acronym ALS stands for Airborne Laser Scanning. Also TLS – Terrestrial Laser Scanning.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe article has been significantly improved. I recommend it for further processing.
