River ice phenology and thickness from satellite altimetry:  potential for ice bridge road operation and climate studies

Zakharova, Elena; Agafonova, Svetlana; Duguay, Claude; Frolova, Natalia; Kouraev, Alexei

doi:https://doi.org/10.5194/tc-15-5387-2021

Articles | Volume 15, issue 12

https://doi.org/10.5194/tc-15-5387-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/tc-15-5387-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 15, issue 12

Research article

|

07 Dec 2021

Research article |

| 07 Dec 2021

River ice phenology and thickness from satellite altimetry: potential for ice bridge road operation and climate studies

Elena Zakharova, Svetlana Agafonova, Claude Duguay, Natalia Frolova, and Alexei Kouraev

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Final revised paper (published on 07 Dec 2021)
Preprint (discussion started on 16 Dec 2020)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'review of work using altimetry data to study river ice', Anonymous Referee #1, 04 Feb 2021
- AC1: 'Reply on RC1', Elena Zakharova, 15 Mar 2021
RC2: 'Review of River ice phenology and thickness from satellite altimetry', Anonymous Referee #2, 08 Feb 2021
- AC2: 'Reply on RC2', Elena Zakharova, 15 Mar 2021

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Publish subject to revisions (further review by editor and referees) (19 Mar 2021) by Moritz Langer

AR by Elena Zakharova on behalf of the Authors (15 Apr 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (20 Apr 2021) by Moritz Langer

RR by Anonymous Referee #2 (25 May 2021)

RR by Anonymous Referee #3 (02 Jun 2021)

Suggestions for revision or reasons for rejection

Summary:
In this study, the authors have developed an algorithm to derive river ice phenology and thickness from satellite altimetry more specifically using the
backscatter coefficient. The paper intends to provide complementary methods to estimate ice phenology and thickness as these parameters are important for ice road safety and climate studies. The results were compared to in situ data. Though the algorithm to predict the date of ice onset and melt is premature, the overall result has potential and adds value. Before the paper potentially can be accepted I recommend some changes. Please, see the comments below

General comments:

1) The methodology is only vaguely described, this needs to be improved. In section 4.1 a flow diagram could help to show the algorithm and then adding a more mathematical description would also help. Please, also provide more detail regarding the manual approached which seems to work better. In 4.2 It is not clear how it was decided that expression (1) was the best choice. If possible please add a figure that demonstrates how the relationship between the accumulated backscatter and the in situ ice thickness was established and what it looks like.

2) The method sections should be expanded with a section describing how the results are validated and all the additional analysis performed, which currently is described in the result section.

3) Currently, the result section is a mixture of results, methods, and an interpretation of the results. Though, a matter of style, this in my opinion makes the paper difficult to read and understand. In this case, it is more difficult to separate the actual result obtained from data, methods, and statistics from the author's interpretation. I, therefore, recommend rearranging this section, so the result section only objectively presents the results.

4) Section 3.2, I do not understand why this section is in the data section, since you do not use the waveform info in the algorithm, or am I missing something. I would not expect that you will find two peaks (related to the ice/air and ice/water surfaces) in a Jason waveform due to the bin distance of 46 cm and an expected ice thickness of approximately 1 m, at least not often. The two peaks are not clearly seen in figure 4. Maybe this section should be moved to a discussion section regarding improving the algorithm.

5) In the discussion section I lack some comments on the strengths and weaknesses of the method and its use. e.g. One limitation is that you need in situ data to establish the thickness relationship, but if the relationship can be applied for another river it will add value.

6) The paper contains many language errors and should be proofread by a native English speaker or a proofreading service.

Specific comments

Title: consider changing it to "River ice phenology and thickness from satellite altimetry. Potential for climate studies and ice bridge road operation

L 61-62: How does this work, maybe add a sentence.
L 63: "High resolution" please define.
L 114 "installation of .." -> "formation of "
L 122-123: Do not write "significant" unless you have performed a test
L 171. "In our previous studies (Kouraev et al., 2005; Zakharova et al., 2019, 2020), we noted that over" -> Previous studies (Kouraev et al., 2005; Zakharova et al., 2019, 2020), showed ..."
L 322 What do you mean by an "acceptable accuracy"?
L 335 "A significant difference" rephrase if you have not performed a test
L 350: "Error" is an imprecise formulation please clarify; RMSE, sd, ...

+ several languages errors not specified

Figures:

Figure 1: Please add lines to indicates the branches of the Ob River. Color code the VS used as training and test.
Figure 3: Are the red lines based on in situ data? please explain in the figure text.
Figure 6: put the three figures on one line

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ED: Reconsider after major revisions (further review by editor and referees) (10 Jun 2021) by Moritz Langer

AR by Elena Zakharova on behalf of the Authors (10 Aug 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (19 Aug 2021) by Moritz Langer

RR by Anonymous Referee #3 (03 Sep 2021)

RR by Anonymous Referee #2 (13 Sep 2021)

ED: Publish subject to minor revisions (review by editor) (15 Sep 2021) by Moritz Langer

AR by Elena Zakharova on behalf of the Authors (18 Oct 2021) Author's response Author's tracked changes Manuscript

ED: Publish as is (01 Nov 2021) by Moritz Langer

AR by Elena Zakharova on behalf of the Authors (08 Nov 2021)

Short summary

The paper investigates the performance of altimetric satellite instruments to detect river ice onset and melting dates and to retrieve ice thickness of the Ob River. This is a first attempt to use satellite altimetry for monitoring ice in the challenging conditions restrained by the object size. A novel approach permitted elaboration of the spatiotemporal ice thickness product for the 400 km river reach. The potential of the product for prediction of ice road operation was demonstrated.