Interannual Variability of Water Level in Two Largest Lakes of Europe

Round 1

Reviewer 1 Report

in the paper,the R, the correlation coefficient , and  R²  , coeffieient determination are used to verify  the accuracy of simulation results. in  hydrolgy modelling, R can not be used to represent the accuracy. in  general , the root mean square error or Nash-SUtchiffe coefficeent  are used. please use this.

Author Response

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Reviewer 2 Report

 

Review of

“Interannual Variability of Water Level in Two Largest Lakes of Europe”

by  Andrey G. Kostianoy*, Sergey A. Lebedev, Evgeniia A. Kostianaia and Yaan A. Prokofiev

 

The authors have carried out an interesting study about investigating the interannual variability of the level of Ladoga and Onega lakes comparing three specialized altimetry databases versus in-situ records at water level gauge stations. Moreover, information on air temperature and precipitation acquired at three meteostations located at Ladoga and Onega lakes was used to investigate interannual trends in the regional climate change. Finally, the authors discuss the potential impact of the lake level rise and regional climate warming on the infrastructure and operability of railways in this region.

The objective is clearly stated at the end of the introduction section, the paper is pretty well referenced and most illustrations are also in good shape. Moreover, the ms is interesting, well-written and easy-to-read. However, the title does not reflect the content of the paper and the organization is susceptible to being improved.  The ms needs a Study Area section, Methodology must be completed and part of the discussion have to be moved to the Results. Furthermore, a most effective Discussion should be performed as some of the Conclusions had not been analysed previously. Thus, in my humble opinion, I really think this paper could be accepted for publication as soon as some medium revisions had been performed. Some typos and specific comments are presented in the attached pdf file.

 

Comments for author File: Comments.pdf

Author Response

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Reviewer 3 Report

This paper investigates the interannual variability of the level of Ladoga and Onega lakes, according to satellite altimetry data for 1993-2020. The authors used three specialized altimetry databases: DAHITI, G-REALM, and HYDROWEB. Water level data from these altimetry databases were compared with in-situ records at water level gauge stations. Information on air temperature (1945-2019) and precipitation (1966-2019) acquired at three meteostations located at Ladoga and Onega lakes was used to investigate interannual trends in regional climate change. 

In general, studies comparing different data for the Two largest Lakes of Europe are important for resolving the Interannual Variability of Water levels in these Lakes.  In this manuscript, there are two significant shortcomings that need to be addressed; first, it is not clear how the different products (DAHITI, G-REALM, and HYDROWEB) are being used.  
Water level data from these altimetry databases were compared with in-situ records at water level gauge stations.  It is not clear what the originality of the study is.  Is this the first such study, there are no others? Finally, what differentiates this work from other similar works?
Overall, this could be an interesting project. However, in the current state, and with the current results, I cannot recommend without substantial revision and improvement. There is certainly value in research, even when we find few or no relationships, as is the case here. That the manuscript should be revised before another submittal.

Specific comments:
However, the manuscript needs some clarification about the methodology to estimate linear trends (amplitudes and other factors)and their errors. 
Has seasonality been removed when estimating the linear trend? 
"For Lake Onega, the situation is different" - probably unnecessary this sentence.
Table 6. - maybe e.g. instead of 0.839224 it is 0.84.
What does a "positive trend".

Author Response

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Round 2

Reviewer 1 Report

please explain the meaning of R² coefficient determination and its difference with the E, correlationcoefficient.  

 

Author Response

Comment by Reviewer 1, Second round

Please explain the meaning of R² coefficient determination and its difference with the E, correlation coefficient.  

Dear Reviewer 1,

The correlation coefficient R is a measure of linear correlation between two data sets. It is the ratio between the covariance of two variables and the product of their standard deviations. It is a normalized measurement of the covariance, which has a value between −1 and +1. In general, the coefficient of determination R² is a measure of how well the observed outcomes are reproduced by the model. For the case of the linear regression, R² is equal to R*R (square of the correlation coefficient).

With best wishes,

Andrey Kostianoy

Reviewer 2 Report

Thanks to the authors for their thorough revision of the manuscript which has improved it greatly

Author Response

Thank you very much for the support of our manuscript.

With best wishes,

AK

Reviewer 3 Report

The authors of "Interannual Variability of Water Level in Two Largest Lakes of Europe " have incorporated the main suggestions from the revision, therefore this reviewer has no problem recommending acceptance of the manuscript in present form.

Author Response

Thank you very much for the support of our manuscript.

With best wishes,

AK