Satellite radar altimetry for monitoring small rivers and lakes in Indonesia

Sulistioadi, Y. B.; Tseng, K.-H.; Shum, C. K.; Hidayat, H.; Sumaryono, M.; Suhardiman, A.; Setiawan, F.; Sunarso, S.

doi:https://doi.org/10.5194/hess-19-341-2015

Articles | Volume 19, issue 1

https://doi.org/10.5194/hess-19-341-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/hess-19-341-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 19, issue 1

Research article

|

19 Jan 2015

Research article |

| 19 Jan 2015

Satellite radar altimetry for monitoring small rivers and lakes in Indonesia

Y. B. Sulistioadi, K.-H. Tseng, C. K. Shum, H. Hidayat, M. Sumaryono, A. Suhardiman, F. Setiawan, and S. Sunarso

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Final revised paper (published on 19 Jan 2015)
Supplement to the final revised paper
Preprint (discussion started on 10 Mar 2014)

Interactive discussion

Status: closed

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

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- Supplement

RC C850: 'hess-2014-8 : Satellite Radar Altimetry for Monitoring Small River and Lakes in Indonesia', Anonymous Referee #1, 08 Apr 2014
- AC C1249: 'Response to Referee #1 Comments', Yohanes Budi Sulistioadi, 05 May 2014
RC C901: 'Review of "Satellite Radar Altimetry for Monitoring Small River and Lakes in Indonesia"', Anonymous Referee #2, 12 Apr 2014
- AC C1252: 'Response to Referee #2 Comments', Yohanes Budi Sulistioadi, 05 May 2014

Peer-review completion

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

ED: Reconsider after major revisions (21 May 2014) by Paola Passalacqua

Dear Dr. Sulistioadi,
Thank you very much for submitting your manuscript “Satellite radar altimetry for monitoring small river and lakes in Indonesia”. I have reviewed your manuscript, the comments submitted by the reviewers and your replies. I agree with the reviewers in the need for more detailed information on the methods used and the assumptions adopted in your analysis. If I were a reader that wants to reproduce your analysis, I would find myself unable to do so. How to select the waveforms and how to define the ranges should be clear. Also, many statements in the paper are vague. For example, reviewer 2 points at a need to be more specific in statements such as ‘reasonable accuracy'. Your proposed change to 'similar accuracy as shown by other studies' is not enough – can you be specific and list what level of accuracy are we talking about here?
I agree with the reviewers that the topic is important, but I find the level of information and quality of presentation of the results in the current manuscript below the level required for publication on HESS. I also echo the reviewers in the need of presenting the conclusions on your paper only if solidly backed-up by your analyses, while some of the results you are presenting cannot be validated. I will reconsider this manuscript if the major concerns expressed by the reviewers will be properly addressed. Make sure to consider each comment carefully, and be detailed and specific in your revised manuscript. The method has to be reproducible by the reader. I would also move some of the tables as supplementary material, while keeping for the manuscript only the most important information. Language and grammar need also to be improved throughout the manuscript.
One other option which I would like you to consider it to re-submit this manuscript as a technical note. The material seems to be more appropriate for a technical note than for a research manuscript and the length of the published paper would likely be within a few pages, particularly if reducing the study cases to what can actually be demonstrated and reducing the tables. I invite you to consider this option. I will reconsider this point after the submission of your revised manuscript.
Thanks again for submitting your work to HESS.
Sincerely,
Paola Passalacqua

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AR by Yohanes Budi Sulistioadi on behalf of the Authors (02 Jul 2014) Author's response Manuscript

ED: Referee Nomination & Report Request started (12 Jul 2014) by Paola Passalacqua

RR by Anonymous Referee #1 (28 Jul 2014)

Suggestions for revision or reasons for rejection

Review for the revised version:
Satellite radar altimetry for monitoring small river and lakes in Indonesia
By
Y. B. Sulistioadi1*, K.-H. Tseng, C. K. Shum, H. Hidayat, M. Sumaryono, A. Suhardiman, F. Setiawan, and S. Sunarso
Anonymous (Reviewer)
General comments
One of the basic premises of this study is to improve the returned RADAR altimetry echoes/waveforms from inland water bodies by carefully filtering out the non-water surface affected waveforms. Authors used these filtered waveforms after removing the outliers to monitor surface water levels and validated these space based measurements with the in-situ measurements. Currently, the operating altimetry missions were primarily designed to study the ocean surface levels. However, retracking the waveforms returned from overland allows altimetry data to retrieve surface water levels for the small water bodies and narrow rivers. Authors propose to classify the retracked waveforms into categories that primarily based on the reflectance characteristics of the inland water bodies (river and lakes). They consider the fact that inland waters are smoother than the ocean surface so as the reflectance are more mirrorlike from the inland water bodies than the diffuse reflectance coming from the ocean surface. They hypothesized four characteristic waveforms from inland bodies based on landsurfce/vegetation and boundary conditions and chose two appropriate waveforms as qualified waveforms for the retrieval of surface water levels. They test their approach to monitor surface water anomalies from a small river (40-200 m), a medium river (200-800 m) and two lakes (<1000 $\km^2$) in Indonesia, a tropical part of the world.
Given that I still have some concerns on the followings:

As has been documented by previous authors, the retrievals of water level become extremely challenging even for a medium size river (40-800 m). In this manuscript, authors also experimented on the river level retrievals in which the river widths varied from 8-45 m. In this experiment, the authors cannot even identify the crossing point from the Landsat data (resolution 30 m). The authors' use 1 m pan-sharpened IKONOS data to identify the crossing point between the river and the altimetry ground track. No Validation has been carried out. As far as I see, there is so much of uncertainty of their experiment for the water level retrievals for widths between 8-45 range. Furthermore, the comparison of the water level anomaly data and with the TRMM data (Figure 8) does not provide any added information to the manuscript. It is very hard to see if there is any correlation between these two variables. So, would you please provide any single reason that why you need to keep this section in this manuscript? (Line no 8, Page 10)

Some minor comments are given below.
Specific comments:
Page 10:
Line no 6: I see roman numerals (i) in the text in line no 16 in page 10. There is no continuation of that numbering system further in that paragraph. Please either continue it or remove it from the text.

Please provide the (a), (b)...(h) numbering for the different tiles in Figure 3. Please refer each figure number when you discuss it in the text.
Furthermore, I would like to mention here that Michailovsky et al. (2012) provided the highest weight coefficient to water waveform, whereas other waveforms get lower weight coefficients in their approach to select the most appropriate waveforms that are less contaminated by land. Any comments about the pros and cons between two approaches are helpful for the readership. They also have an outlier removal methods based on the statistical properties of the waveforms.

Line no 22:
Page 11
Line no 11: Citation for the reference is not correct. The "deSa, 2007" needs to be corrected as "de Sa, 2007".
Furthermore, this citation is also not correctly given in the reference section. The correct reference should be as follows (Please format it according to the journal style):
De Sá, J. P. M. (2007) Applied Statistics Using SPSS, STATISTICA, MATLAB and R. 2nd edition. Springer-Verlag, Germany.

Page 12
Line no 28: please replace "best" from "better"

Page 13 and Page 14
Line no 27-4: I strongly question about the section from Line number 27 (page 13) - 4 (Page no 14). This section does not add anything to this manuscript. It is questionable on how authors can make a recommendations based on something that they have not really shown in the manuscript.

As authors pointed out in their manuscript, the footprint of the Envisat is ~850x2 m (Line no 8, Page 10). As has been documented by previous authors, the retrievals of water level become extremely challenging even for a medium size river (40-800 m). In this case, authors are experimenting on river widths ranging from 8-45 m. Authors even cannot identify the crossing point from the Land sat data (resolution 30 m). The authors' in this case use 1 m pan-sharpened IKONOS data to identify the crossing point between the river and the altimetry ground track. No Validation has been carried out. As far as I see, there is so much of uncertainty of their experiment for the widths between 8-45 ranges. Furthermore, the comparison of the water level anomaly data and with the TRMM data (Figure 8) does not provide any added information to the manuscript. It is very hard to see if there is any correlation between these two variables. So, would you please provide any single reason that why you need to add this section into this manuscript?

Line no 18/19: Please either use Fig. x or Figure x. Please be consistent with whatever you selected throughout the manuscript text.

Referee Report: PDF

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RR by Anonymous Referee #2 (04 Aug 2014)

ED: Reconsider after major revisions (18 Aug 2014) by Paola Passalacqua

AR by Yohanes Budi Sulistioadi on behalf of the Authors (29 Sep 2014) Author's response Manuscript

ED: Publish subject to minor revisions (Editor review) (16 Oct 2014) by Paola Passalacqua

Dear Dr. Sulistioadi,
Thank you for submitting the revised version of your manuscript and addressing the reviewers’ comments. There is still editing needed for this manuscript before publication. I list below several corrections and please pay particular attention to your introduction and conclusions; the material in between appears to be more polished, but the intro and conclusions need work.
- page 4 line 4: while medium rivers are defined as those with
line 9: challenge
line 12: A number of researchers
line 14: develop a global
line 15: accounts
line 20: as well as recent ones
line 24: repeats
line 24: repeat period for
line 28: of the returned
- page 5, line 4: belong
Line 8: why is there a question mark after power spectra?
Line 16: by adding a
Line 19: introduced the Sea
Page 6, line 3: procedures
Line 5: period after ‘interest’
- Page 7, line 2: wetlands form
Same line, what does ‘fitth hundreds kilometres’ mean?
Line 5-6: need rephrasing, the part starting with ‘agricultural farms’ does not work with what is in the sentence.
- Page 8, lines 9-10: needs rephrasing. ‘are then averaged’? ‘into 18’
- Page 9, line 9: of the remote sensing imagery
Line 14: ‘Previous work’ or ‘A previous study”
Line 16: ‘hypothesis’
- Page 10, line 6: by other surfaces
Line 19: further processing
- Page 11, line 19: ‘sample’ may be a better word than ‘measurement’
- Page 16, line 19: of monitoring
Lines 21-24: needs rephrasing. Separate into two sentences? Or delete from ‘further highlights’
Page 17, line 1: needs rephrasing. ‘In contrast to what previously found’
Line 5: RMSE used earlier. The sentence needs also rephrasing. Remove the i.e. portion or put in (), and the average of what quantity?
Line 7: ‘water body’ the line also needs rephrasing. ‘is the smallest water body analyzed from satellite altimetry’?
Line 9; ‘encountered in our analysis’
‘selection of a range of measurements’
‘its waveform shape’ refers to? Unclear from the sentence

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AR by Yohanes Budi Sulistioadi on behalf of the Authors (22 Oct 2014) Author's response Manuscript

ED: Publish subject to technical corrections (04 Nov 2014) by Paola Passalacqua

AR by Yohanes Budi Sulistioadi on behalf of the Authors (10 Nov 2014) Author's response Manuscript

Short summary

This paper investigates the possibility of monitoring small water bodies through Envisat altimetry observation. A novel approach is introduced to identify qualified and non-qualified altimetry measurements by assessing the waveform shapes for each returned radar signal. This research indicates that small lakes (extent < 100 km2) and medium-sized rivers (e.g., 200--800 m in width) can be successfully monitored by satellite altimetry.