Spatiotemporal Filtering for Continuous GPS Coordinate Time Series in Mainland China by Using Independent Component Analysis

Round 1

Reviewer 1 Report

The noise model is constructed based on AIC and ICA for crustal movement in China. It may be interesting to analyze the relationship between AIC and ICA because AIC depends upon the number of parameters while ICA gives the appropriate number of parameters.

Author Response

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Reviewer 2 Report

Many thanks for having submitted your article. Generally, the article is well written. However, I have some concerns about the novelty of such a study and I find that the conclusions could be slightly deeper in terms of interpretation.  More specifically:

the figures (5,8) are not described with enough detail in the text making a proper interpretation difficult. I had trouble orientating myself as I do not know the name of the Chinese regions so that I would suggest adding them in FIgure 1.

Furthermore, I do not understand the necessity to have figure 3, 4 and 7. which are not adding content. Additionally: could you please comment why you made investigations on WN+FN, PN and WN+FN+RW and not just on the optimal noise model chosen with AIC?

I would like to have more comments on figure 5 regarding geophysical interpretation. I do not understand what is meant page 11 under ""good uniform characteristics" and how you judge such features. Why are you relating these signals to geographic factors? 

What is the relationship between figure 5 and 8 if any?

I  could not understand Figure 8, particularly b,c,d. COuld you please make a better description and interpretation of it. I would like to know which insights they give to the study. What would be the conclusions from them

The beginning of the abstract should not contain "it", what do you mean here? I would suggest rephrasing the whole abstract. Otherwise, the rest of the article is well written and understandable.

I would be please to review a revised version of the manuscript that would describe the figures with more details, providing a slightly improved interpretation (particularly figure 5 and 8)

Author Response

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Reviewer 3 Report

This is a nice piece of work regarding spatio-temporal signals of crustal motion over Mainland China, measured by GPS techniques over long periods of time. The paper is well written and the results are interesting. I have very few points to be addressed by the authors and a general comment on their results.

Minor points:

[1] The reference number should accompany the author's name in the text. 
Example Line 56: 'For instance, Zhang et al. [6]...' . This facilitates the reader to locate the paper involved. Please follow this suggestion allover the text. In line 65, and line 80, separate the names and references from each other, if you wish to keep the names.

[2] Lines 300-307. Check the paragraph outlook. Also define spectral index, and how do you determine them (Table 2).

[3] Explain notation used in lines 318-323 and Figure 7, regarding year^(1/4), year^(-k/4) and year^(1/2).

[4] Give units in Table 3.

Comments:
The ICn time series shown on top of Fig.5 seem to be one of the main results of the paper. They look sometimes quite non-stationary, which make them rather interesting. Perhaps the authors should give a look at the paper by Bunde et al., Physical Review Letters, 81(3), p.729 (1998) [*], in which an
accurate analysis of time series is done. It is not required that the authors add additional calculations, but a pertinent discussion on the calculation of the so-called Hurst exponent, denoted as alpha in [*], is related to the spectral index, called gamma in [*]. Some comments on this comparison, which leads to the concept of colored noise, would be beneficial for the readers, and possibly for future investigations by the authors.

Author Response

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Reviewer 4 Report

The Abstract is poorly drafted, i.e., ... it provides a great opportunity ..., ... it helps to estimate a reliable and accurate velocity ... — what do the authors imply by 'it' here? The problem is, in fact, of the Sentence Structure that has caused this.

The Abbreviations should be redefined in the section, Introduction (or in any other appropriate Section), since the Main Body of a manuscript starts from there, i.e., please remove all the Abbreviations that have not been employed in the Abstract and ones which have been used there needs to be redefined again in the Introduction (or in any other appropriate Section).

The Research Design, particularly in Section 2.1, needs to be delineated in a much more categorical manner.

Is there a better way to present Figures 5 - East, North, and Up? The authors should be able to present these Figures as one single concatenated Figure.

The section, Conclusion, should be perhaps renamed as Conclusion & Future Directions, or to a similar variant, and probable Future Work should be thus clearly delineated in the same.

The cited Literature is pretty outdated, i.e., it is always recommended to cite the Scholarly Work from within the past three, or at the most, past five years with an exception of the early Seminal Works.

There are considerable number of issues with respect to the Language and the Sentence Structure and a careful proofreading is highly indispensable.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 4 Report

Thank you for incorporating the changes which have undoubtedly enhanced the quality of the manuscript-at-hand.

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.