Assessing and Predicting Nearshore Seawater Quality with Spatio-Temporal Semivariograms: The Case of Coastal Waters in Fujian Province, China
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsI congratulate the authors for the excellent article. The introduction is very thorough and reviews the state of the art. The English is very fluent and easy to read. The theoretical concepts and the results of their application are well presented, but I only have a few comments and suggestions to improve your work:
page 7 - line 222 - words Variogram ST; R and gstat - could be higligthed, as they are functions of the R software;
page 8 - lines 227-230 - graphics a, b, c, d e and f of figure 5 should be in the same page;
page 9 - figure 6: (i) it is not clear the fitting of the teoretical and the empirical variograms; (ii) the scale of the empirical and theoretical graphics (variograms) must be the same; (iii) the range of each variogram could be enhanced by a sign; (iv) the dimension of the text in the graphs could be improved.
page 9 - differences between the range of the empirical and the theoretical variograms should be commented and presented in table 1.
page 10 - line 296: words krigeST and gdstat are functions of the R software and should be in italics;
page 10: figure 7: scale of map (c) should be the same as the other maps (a-f);
page 11 - line 319: it should be explained how the maps in figure 9 were obtained: (i) by Indicator (or morgological) kriging method, based on the indicator formalism or; (ii) by ordinary kriging, followed by a reclassification of the matrix obtained. Depending on the method used, the results vary. The most suitable method for estimating indicator variables (as it seem to be the case) is the morphological kriging method, so a commentary on the method used, its advantages and restrictions should be presented.
page 12 - line 326: it should be referred the basis of the kriging method (indicator kriging or ordinary kriging) used to achieve the grade results.
I sen in attached the pdf with the suggestions
Thank you
Comments for author File: 
Comments.pdf
Author Response
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Reviewer 2 Report
Comments and Suggestions for AuthorsOverall, spatial-temporal geostatistical methods are not new in water quality estimation, therefore, this study is not novel in this filed. Despite the authors claimed spatial-temporal geostatistics application seawater is "new" (from the abstract). Based on the method, I did not find the method is a newly proposed method, instead, the authors used existing method and packages.
My biggest concern is in Line 213, about the data used in the study: "We use the last five years (2019–2023) of annual water quality data..." what is the temporal resolution of the data? If each each year has only one value for each location, the whole method is not valid in this study.
The introduction referred a lot of research based on AL/ML, while the whole work they did have nothing to do with AL/ML, nor any comparison in the discussion with AL/ML. It's important to present the cutting edge research in seawater quality filed, however, the purpose of including them is to support the necessity of your research. This part need to be heavily modified. Based on my knowledge, AI/ML requires high quality data, which is alway challenging in water quality.
In the method, a lot of the equation are not necessary, since you are not developing new methods, all you presented are others' work. You can simplify these. Also, figure 1 is not needed, just define these terms (e.g., sill) in text.
In the results, all figures are hard to read. The common issues are: the texts too small, the resolution is too low, legend hard to read, the colors in the maps cannot be differentiated from each other (fig 3,4; fig 7, 8).
Comments on the Quality of English Language
The actual English is good in this manuscript, but there are a lot of terms are not appropriate. For example, "diluted water" (Line 193), I am not sure what do you mean; kriging is not an algorithm (Line 355)
There are a lot of vague expression in the paper, for example, Line 244-245: "show a certain degree of correlation over time", this need to be quantified like "how many days or month?" In table 1, what are the units?
Some repeats in the writitng, e.g., Lines 344-346 says the same thing as Lines 340-343. Lines 349-251 repeated the previous sentences.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThank you for your invitation to " Assessing and Predicting Nearshore Seawater Quality With Spatio-Temporal Semivariograms: The Case of Coastal Waters in Fujian Province, China ". This study proposes a new method that applies the kriging interpolation algorithm to empirically generated spatio-temporal semivariograms to assess and predict seawater quality. I read the manuscript carefully, I think the manuscript still needs a lot of improvement before it can be published.
1. In the method section, after 101 lines are written, you can directly introduce the algorithm used in the experiment, instead of writing a bunch of hypotheses, expressions such as suppose and if we suppose do not need to appear in the method part. By the way, I suggest the author can concise the method section.
2. Line 140 “….we are doing here”, the expression too colloquial.
3. The Figures that appear in the paper does not look very clearly, suggest the authors can adjusting it?
4. The line 232, the author shows the Figure 4. But I think it is not Figure 4, should Figure 5.
5. It would be better to put the introduction of the model in section 3.4 in the method section, and it is enough to write the analysis of the experimental results here.
6. In section 4.1, time series trend analysis can be added based on the results.
7. In line 316, since inorganic nitrogen and reactive phosphate are the primary factors that exceed the secondary category in the coastal waters of Fujian, the argument for this as the main influencing factor does not seem convincing.
8. The final summary part can be listed in sections to highlight the key points.
9. Discussion section is very important in the paper. Readers can understand the current research deficiencies and prospects through discussion. So, please added discussion part.
However, I believe that this manuscript could make more contribution to this research filed, and suggest that the author carefully revise.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for Authorssome minor comments as follows:
1) Is there any adjustment rule for model parameters. Please explain it clearly.
2) The final conclusion is not listed in sections, and only explains the advantages of the algorithm, without telling the important conclusions of the experiment in the paper. and the contribution of the paper is not clearly written.
Author Response
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Author Response File: Author Response.pdf
