Ground-Based Radar Interferometry of Sea Ice

Round 1

Reviewer 1 Report

This work is a comprehensive description of the potential and capability of the Gamma portable radar interferometer to assess the dynamics and morphology of sea ice. The manuscript is well organized, the exposition is fluid and the approach is rigorous.

I do not have particular comments to raise as I believe the paper deserves to be published in the present form.

 

Author Response

Dear reviewer,

We greatly appreciate your time and effort reviewing this manuscript. Thank you very much. 

With best regards,

Dyre Dammann

Reviewer 2 Report

The paper describes the results of a ground-based interferometric experiment in the Arctic to measure strain on ice floes. It includes the desciption of observation geometry, the measurement principle, a sensitivity analysis, simulation results and a discussion of real strain measurements and potential error sources.

Although validation data are missing, the presented elaboration is self-contained and convincing. To my knowledge, the paper is the first of its kind and thus merits publication.

However, there are a couple of statements requiring correction and/or additional explanation:

1. Section 2.1.: Interferomtry is a more general concept than just for measuring displacements. As detailed in eq (1), it can be used for topographic measurements, or atmospheric delays as well. Pls. reformulate!

2. Eq (7): In Fig. 1 B_s is B. Pls adjust for consistency. Is h_a given for \alpha = 0. Pls. clarify! Also the second and third term are usually negligible. Pls comment!

3. Eq. (11) does not describe the height std. Pls. correct the statement in line 133 or introduce a further equation for the height std.

4. Fig. 3 (b) and (d): Warm legend colors do not fit the lines in the plot. Pls. check!

5. Line 210: " A tilt will potentially reduce \gamma_sp (Eq. 8) resulting in increased noise (Eq. 10 and 11)." I do not agree with this rather general statement. \gamma_sp has not been quantified in this paper.
In my opinion, a tilt of few degrees will not impact the coherence noticeably. When answering this question, please indicate the bandwidth of the radar. This parameter has not been given so far.

6. Line 238: Pls. delete the last part of the phrase (starting from ",and thus tilt ...", as there are no errors in slant range due to tilt. Fig 3d shows errors in height.

7. Line 318: ERA5 is undefined. Pls. introduce the abbreviation and give proper citation.

8. Line 321: 0500 -> 05:00, 0700 -> 07:00

9. Line 329ff: Strain and strain rate are the main quantities derived from the interferometric measurements. However, there is no explanation given, how these two quantities relate to the measured observable (displacement in LOS). What are the respective measurement units? A clear explanation is also needed for the choice scanning mode for strain and stare mode for strain rate.
How do you compute the average strain rate "between acquisitions"? What is the standard deviation?

10. line 355-356: There is a reference to Fig 6(c) at this point, which I could not understand. Scan measurments and stare measurement are presented for different days. The first (March 10) discusses shear strain, whereas the second (March 4) concludes convergent strain. Given that these are taken on different days, why do you claim consistency? Additional explanation is required at this point!

11. Figure 9 caption: There is no parametrisation concerning the number of looks in Fig9(c). Remove "and number of independent looks" or state "and assuming 4 independent looks".

 

Author Response

Please see attachment

Author Response File: Author Response.pdf