Multiscale Variability and the Comparison of Ground and Satellite Radar Based Measures of Peatland Surface Motion for Peatland Monitoring

Round 1

Reviewer 1 Report

The article is important for understanding the relationship between peatlands and climate changes. It should be emphasized that not only climate and weather affect peatlands, but peatlands also affect the climate in the long term, because they are not only a carbon storage and actively absorb carbon from the air in their growth.

Second remark: the study would be more complete if the results of measurements in the visible, infrared and, possibly, radio ranges made from UAVs or manned airplanes were added.

Author Response

Thank you for the kind review

Second remark: the study would be more complete if the results of measurements in the visible, infrared and, possibly, radio ranges made from UAVs or manned airplanes were added.

Although this would indeed be interesting it is felt that this is out of the scope of this study and would add additional complexity

Reviewer 2 Report

Thanks for your work. Frankly speaking, it is great, but there is some small questions needed to be addressed before publicaiton

1. The Keywords is too many, you can do some selective it would be better
2. The introduction is detailed, but it is too long, making it a little bit challenging for reading.
3. In line 126, what if you can define the specify the SAR image? Sentinel or Terra-X or ALOS? Since different sensors have different resolutions. Similar in 253, I think you can check this resolution, because if you use 5*1 multilook, the resolution will be 25 to 30m, if you 15*3 multilooks,
4. In figure 1 , can you label the number on the figures?
5. In line 245, Terra Motion Limited’s in-house 245 Punnet software is free-download or commercial? l, if it is free to access, you can give the website. The read would be greatly appreciated.
6. In line256, please cite the reference for the equation V_vert
7. In result part, Site M-F show obvious fluctuation, whether it contains some uncertainty from processing INSAR, because this value seems too large amplitude.
8. In your discussion part, why you didn’t consider the soil moisture is also a disturbance factor for your result. In addition, Using a simple equation to transfer velocity along LOS into vertical direction, also provides extra bias.

Author Response

1. The Keywords is too many, you can do some selective it would be better

Reduced

1. The introduction is detailed, but it is too long, making it a little bit challenging for reading.

We have attempted to make this more concise, although feel this is required to properly cover the limitations of the ground techniques as these are often underestimated

1. In line 126, what if you can define the specify the SAR image? Sentinel or Terra-X or ALOS? Since different sensors have different resolutions. Similar in 253, I think you can check this resolution, because if you use 5*1 multilook, the resolution will be 25 to 30m, if you 15*3 multilooks,

The SAR image is Sentinel-1 although the pixels are resampled to 80x90m during the APSIS processing, clarified in text

1. In figure 1 , can you label the number on the figures?

I have corrected the figure caption to make clearer but am currently unable to make changes as I am away from the office

1. In line 245, Terra Motion Limited’s in-house 245 Punnet software is free-download or commercial? l, if it is free to access, you can give the website. The read would be greatly appreciated.

The Punnet software is a patent pending commercial software used exclusively by Terra Motion Ltd

1. In line256, please cite the reference for the equation V_vert

_{This is just common knowledge, derived from geometry and so no reference is available}

1. In result part, Site M-F show obvious fluctuation, whether it contains some uncertainty from processing INSAR, because this value seems too large amplitude
2. Yes this is a result of the actual motion exceeding the ambiguity threshold during unwrapping which leads to the odd fluctuations, this is a clear limitation of the approach, clarified in text further
3. In your discussion part, why you didn’t consider the soil moisture is also a disturbance factor for your result. In addition, Using a simple equation to transfer velocity along LOS into vertical direction, also provides extra bias

Soil moisture does not decrease below 35% across the drought which according to personal comm with Prof Keith Morrison at U.Reading UK shouldn't impact penetration depth, although this is discussed in the discussion.  We agree and have added clarification in methods, although for the sites chosen these were of limited scale <1km distance and the impact should be minimal.

Reviewer 3 Report

Authors demonstrate the benefit of supplementing traditional field methods with InSAR to monitor changes in surface elevation in different areas of peatlands. Results are promising and can aid in peatland monitoring and conservation, although there are still difficulties with micro-topographic movements and decorrelation from large movements during droughts that are not captured by a relatively coarse-resolution InSAR approach. This is a well-written paper. I am well-versed in InSAR applications and this paper presents a great case study of an application for InSAR peatland-bog monitoring. A have provided a few minor comments below and recommend publication after minor corrections. Well done.

General Comments

Figures: Quality is a bit low, but this may be an artifact with how the PDF was uploaded to the system. Please make sure to check uploaded figure quality before final submission.

Line-by-Line Comments

Line 8: Country (UK)?

Lines 16-17: InSAR is typically an acronym for 'Interferometric Synthetic Aperture Radar'.

Line 76: Open parenthesis and "e.g.," is incomplete here.

Line 144: Please define A.O.D.N. before using acronym.

Line 162: Superscript for km² and remove full-stop (period) "." in "Figure 1".

Line 168: Please provide a brief (1-sentence) explanation for subsite naming, e.g., M-A, M-B, etc. Although this is shown in Figure 1, the subsite naming approach is not described in the manuscript and took some time to realize these are site names. 

Line 174: Are these bulk density measurements correct? Values ranging from 0.044 g/cm3 to 0.061 g/cm3 are much less than water and only one order of magnitude above air. Is the top 50 cm of pool systems mostly composed of gas? Same comment for values in Line 179.

Line 294: Capitalize the word "august".

Line 368: Change ampersand to the word "and".

Author Response

Thankyou for the kind review

Line 8: Country (UK)?

Done

Lines 16-17: InSAR is typically an acronym for 'Interferometric Synthetic Aperture Radar'.

Done

Line 76: Open parenthesis and "e.g.," is incomplete here.

Done

Line 144: Please define A.O.D.N. before using acronym.

Done

Line 162: Superscript for km² and remove full-stop (period) "." in "Figure 1".

Done

Line 168: Please provide a brief (1-sentence) explanation for subsite naming, e.g., M-A, M-B, etc. Although this is shown in Figure 1, the subsite naming approach is not described in the manuscript and took some time to realize these are site names. 

Done now added to line 151-153

Line 174: Are these bulk density measurements correct? Values ranging from 0.044 g/cm3 to 0.061 g/cm3 are much less than water and only one order of magnitude above air. Is the top 50 cm of pool systems mostly composed of gas? Same comment for values in Line 179.

These are typical dry bulk density measurements for the acrotelm from peatland, The vegetation in near natural systems is very loosely compacted and the sample is dessicated for analysis which leads to the values observed by Avercamp et al., 2021

Line 294: Capitalize the word "august".

Done

Line 368: Change ampersand to the word "and"

Done