Water Level Change Monitoring Based on a New Denoising Algorithm Using Data from Landsat and ICESat-2: A Case Study of Miyun Reservoir in Beijing

Round 1

Reviewer 1 Report (Previous Reviewer 1)

The paper is accepted in its current format.

Author Response

Thank you very much for acknowledging our article sincerely.

Reviewer 2 Report (New Reviewer)

Dear authors of the manuscript.

I congratulate you on completing and submitting your article. I read your manuscript carefully. I have several comments on the presented text, which I would like to summarize in the following lines:

- The map image of an area of interest could be more distinctive in the Study Area chapter. For example, the territory of East Asia (possibly also China) with a zoom on the Beijing region and another zoom with a representation of the Miyun water reservoir).

- The authors could have used Sentinel-2 satellite data with better spatial resolution to refine the results (in combination with the Landsat data). 

- Based on what criteria did you decide to use MNDWI when choosing the spectral index of water? Please explain this step in the manuscript.

- Why were only two images from 2008 used for research? Are only two images available with less than 10 percent cloud cover this year? (line 192)

- Authors should keep the text style according to the template, i. e. subsubsections names should not be italic (line 164, 180, 194, 219, 247, 267, 414, and 486)

- It would be appropriate to add an empty line between abstract and keywords (line 43-44)

- Keywords (line 44) should be in the same Palatino linotype font, i. e. like the entire paper.

- The Author Contributions paragraph (lines 617-622) and References paragraph (lines 645-739) sections should contain the same line spacing according to the template.

 

Author Response

According to your comments, I have responded to the reply in Word for your check. Thank you for your valuable suggestions.

Author Response File: Author Response.docx

Reviewer 3 Report (New Reviewer)

The authors investigated the possibility of detecting the water level of Miyun Reservoir dynamically and inverting water level information from unrecorded dates using data from Landsat and ICESat-2 data. A denoising method has also been proposed based on a statistical histogram to process the ATL03 single-photon data to handle the issue of large amounts of background noise in ATLAS laser data.

The corresponding water level was calculated with the obtained regression model based on the images Landsat from 2010 to 2020 the result was compared to the measured daily water level (http://nsbd.swj.beijing.gov.cn/dzxsksq.html 2009-2020).

Line 446 date range 2010-2020 or 2009-2020 as is shown in Figure 13(a)?

Based on the ATLAS laser data extracted the effective elevation information of Miyun Reservoir. What is the correlation between the inversion water level and the real water level from 2018-2020 (Figures 13 and 15) and what is the deviation between the inverted water level and the measured water level after correction and what is the root mean square error (RMSE)?

Editing: Table 1 Confusion matrix and daytime data precision analysis results.

The obtained results between inverted and measured water levels are correlated. The obtained results allow assuming that the proposed method of construction of the area-elevation (A-E) model can provide support for the development of effective monitoring of water level changes in small lakes or reservoirs.

The work is based on the analysis of the current state of the research (section 2.4. Water extraction based on Landsat images ), theoretical description, and experimental verification with the available methods. It brings elements of novelty such as a data denoising algorithm and A-E model construction. I have no major remarks to make from a formal point of view. One can expect interest and adherence in the scientific field.

 

Author Response

According to your comments, I have responded to the reply in Word for your check. Thank you for your valuable suggestions.

Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

This paper is interesting, however, there are some points that need to be considered by the authors in improving the current version of this research paper.

- A thorough proofreading for correcting the language is required.

- Please avoid the terms like "We looked into.." line 26

- Mention the names of the "other time series..."

- the abstract lacks the key findings of this study

- Citation required for lines 49-53

- Is the ESA a sub agency of the EAA? line 71-72

-Follow the numbered format for citing mutli authors e.g. Line 79: Me et al. [?]

- Correct the citation Li et al. [?] line 81.

- Zhang Xin et al [?] line 96

- What do you mean by "Certain penetrability" line 94

- The text requires to be rephrased from line 103-113; the story isn't clear

- To denoise the ICESAT2 data, you chose to apply two approaches but you didn't mention the reason for chosing these algorithms.

- What are the strengths of those algorithms, why would you go for it, what does the published literature say about it.?

- Correct the language "In this study, the research goal of this study is to ...."", line 114.

- What do you mean by " this study has certain reference for .... "

- The novelty of this study hasn't been well-highlighted, the current explanation is not convincing.

- Avoid repetition, merge the text in 129-130.

- Mean annual temperature can be a single digit and not a range e.g. 9-10 degree C

- How is the seasonal change of rainfall obvious unless you report it here? lie 131

- Naming merely 188 sq km as "vast surface" isn't just, avoid adjectives like this throughout the text.

-Use SI units instead. line 133

-Section 2.2.1: There are unnecessary details in this section that can be easily skipped.

-Figure 2: Can you explain this if it is really a histogram?

-Original data? I gues you meant Observed/Measured data? line 176

-Please change the language of your methodology, e.g instead of "the original water data in this paper are mainly acquired...", please use " the field observations used in this study were acquired...." line 177

-Line 181: What is "present", give an exact digit/year instead?

- You can't use imperative sentences e.g. "Sort the data..." Line 183

-Figure 3: Explain it, please.

- Some words have been merged from lines 187-195, correct it to make it meaningful.

- Within the above text, look at the splitout alphabets too, correct it.

-Figure4 : You need to provide this framework just after the study area, the reader can then get an idea/impression of what comes ahead rather than knowing at later.

- The methodology section is extra-large, you need to give preference to the original literature instead of repeating it here. I mean specifically section 2.3.1, 2.4 and 2.5

- The results' section doesn't follow the same pattern as already described int he introduction and methods section, there is a need to synchronize the whole paper.

-Methods and procedures have been mixed with results, lines 349-356

-You can't conclude already at the start of your results e.g. "it has the potential to iprove the ...." lines 369->

-Figure 8: Explain it well please, what do you want to show by this, keep in mind your topic!

-The actual theme of this paper has been put in a very limited space and is extremely descriptive e.g. section 3.3->

-The whole essence of the paper is gone and therefore the conclusions are not solid, the discussion part is not supportive and the authors need to restructure the whole paper.

- The author shall read the authors' guidelines before submitting their manuscript.

-

 

Reviewer 2 Report

The manuscript presents a methodology for water level monitoring of  a reservoir using the altimetric ICESat-2 and Optical Landsat satellites.    Overall this methodology is broadly employed using other satellites and the chosen sensors. This can be easily found in several references and applications in other journals or in the Remote Sensing itself.    In this sense the relevance of the article, as a monitoring methodology, only gains strength when it presents in one of its steps the innovation of the method for obtaining altimetry values from ICESat-2 by a "Noise reduction algorithm for single photon altimetry data". In this sense, I suggested changing the title to highlight this and make the title of the article more appropriate. However, it accomplishes the objective of providing information and even estimation of altitudes using the methods described.   In my view, there is no novelty relative to the methods for obtaining areas by Landsat and combining the percentiles with altimetry to estimate the Dimension-Area models.   Regarding the statistical analysis, the high values are expected, and perhaps similar ones, such as Kappa, could also have been applied.   I am curious regarding the limitations of the methods in terms of reservoir sizes (smaller ones*), or any other sort of limitations for that matter. It would be positive to include in the discussions.   The results were well presented in tables and graphs and provided support to the results/conclusions.   The final paragraph of the conclusions got me puzzled. Is there no information about water uses or human activities in the upper/lower basins of this reservoir? The statement looked too vague and obvious: "We speculate that natural and human activities both contribute to the fluctuation in the water level of Miyun reservoir, the change of water level is mainly affected by human activities, including land use change, increased water consumption due to economic growth, and the South-to-North Water Transfer Project."   Attached you find a few notes in your pdf file.   My recommendation is Reconsider after major revision addressing the points above mentioned.

Comments for author File: Comments.pdf

Reviewer 3 Report

The paper investigates the impact of climate change on water level of inland Miyun Reservoir, which is of importance and applicable to many areas in the world. The authors have done thorough analysis using multi sensor approach including data from Landsat imagery and satellite altimetry to estimate water level elevation. The results were promising and  indicated high correlation coefficient between estimated water level from the inversion method and measured water level. 

The data and methodology have been explained in details. The results and discussion sections were well written. Overall, I enjoyed reading the paper and suggest the manuscript to be accepted for publication after minor corrections. I believe the authors need to include references for the method and equations provided in the section 2.3.1.