Automated Estimation of Sub-Canopy Topography Combined with Single-Baseline Single-Polarization TanDEM-X InSAR and ICESat-2 Data

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Well done to the authors for presenting such a good manuscript. The paper was well written, its very easy to follow and it is of a good scientific quality. There were no major issues detected in this paper apart from the captioning of figures. A standard method of captioning figures is such that the caption can provide enough detail to enable the reader to understand what the figure is shown, without having to revert back to the text. There are several instances where the caption of figures/tables in the manuscript fall short of this standard. May the authors please revise the captions.

Comments for author File: Comments.pdf

Author Response

Dear reviewer:

Thank you very much for your competent comments and helpful suggestions on the manuscript. We have carefully considered your valuable comments and suggestions and give a point-by-point description of how each comment was addressed in the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors propose a process for the computation of the sub-canopy topography from single-baseline and single-polarization TanDEM-X InSAR data using the interferometric coherence and the slope. The study is generally well-written and easy to read. The proposed framework is presented clearly while the process is validated adequately and the computed results are convincing.. The major concerns are as follows.

1) Slope information is important for the proposed method. However, the slope is derived from the TanDEM DEM without removing the canopy height. So, how to consider the impact of slope uncertainty on the results?

2) The use of the inverse ration of the square distance also needs more elaboration with respect to the density of the points, the slope, the complexity of the surface used etc. Please mention advantages, disadvantages and limitations.

3) A global DEM such as the TanDEM-X DEM is computed through optimized processes. And the same exists for the data used for its computation. Does this research propose the re-computation of the TanDEM-X DEM using the proposed process?

 

Minor concerns:

1) In Fig. 1, the variables in the equations were not defined clearly. Therefore, it is difficult to follow the workflow.

2) What do you mean by "'corrected " in Fig. 1? Is it " compensated" in section 2.1? The wording 'corrected coherence' is not appropriate to refer to volume decorrelation, you need to actually calculate it, not correct the coherence. This is one of the most important parameters you are using and it is not clear what it really is.

3) How big is R? how was this value chosen?

4) Do I correctly understand that for each pixel of a given TanDEM-X scene, the SPC is computed independently?

5) Since the proposed method considers steep slope regions, it should be described how the effects of geometric distortions on InSAR are handled.

6) Please pay attention to the correct expression of formula symbols. For example, "R2" of L349 should be "R²", please check carefully

7) The abbreviation of Figure i should be Fig. i, some expressions are missing ".", such as L329.

Comments on the Quality of English Language

Generally, the manuscript is well-written and easy to read except for some minor mistakes.

Author Response

Please see the attachment

Author Response File: Author Response.pdf