How Weather Affects over Time the Repeatability of Spectral Indices Used for Geological Remote Sensing
Round 1
Reviewer 1 Report
The article describes the multitemporal analysis of geological spectral indices using the Sentinel-2 satellite data. As such, the article fits the scope of the journal. The main contribution of the article is the finding that spectral index values depend on the soil moisture level, and the selection of images should aim for the lowest soil moisture condition. An important finding is also the recommendation that all pixels with an NDVI value above 0.1 should be masked to avoid any influence of vegetation. Moreover, the automatic data processing in the Google Earth Engine (GEE) application allows repeating the results.
The manuscript is presented in a well-structured manner. The Introduction section provides a concise picture of the current state of the studied issue. Several sentences should also be added about soil moisture as the main environmental variable of interest, especially its measurement methods and available data sources.
The methods are clearly described and the experimental design is suitable for testing the given hypothesis.
The results are detailed and well documented with graphs. However, a table summarizing the findings of whether the given index increases, decreases or is stable with an increase in soil moisture and amount of vegetation (depending on the type of surface) would help better orient the reader. Comparing the indices with soil moisture and NDVI through correlation analysis and two-dimensional scatterplots could also contribute to the interpretation of the results.
Minor errors:
A small map of the location of the study areas would be useful.
Figure 2 lacks the legend of the geological map, as well as the value ranges of the individual indices.
Author Response
Thank you for your review. Please find our response in the attached document.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The Manuscript is well-designed in a draft that is easy to read and understandable. It is seen that the title of the manuscript is suitable for the content of the study. The abstract does not fully reflect the basic information of the article. In the summary part, unnecessary information about the subject of the study is included. On the other hand, information about the interesting aspects and accuracy of the results of the study was not given. The importance and originality of the study are not emphasized in the abstract. The problem and hypothesis question addressed by the research are stated in the manuscript. However, in the introduction part, the original aspects of the study subject compared to the studies in the literature are not emphasized enough. It is seen that the results obtained in the study are generally consistent among themselves. The purpose of the study is well stated. However, the contribution of this study to the literature is not emphasized in the discussion section. Therefore, comparisons should be made with the literature studies on this subject and the results should be interpreted. For this purpose, new references can be added so that the importance and place of the study subject in the literature can be adequately understood.
My other suggestions about Manuscript are presented as follows:
Page 3 line 91
More detailed information about Table 1 should be given in the text. More detailed information should be given about the words "modified" and "translated" used in Table 1.
Page 4 line 150
In the sentence “The years 2018 and 2020 both had a single dry period in the summer”, the period numbers and the names of the months should be clearly stated.
Page 5 line 158
The sentence “In all years, the radiation flux was in spring (March–April) generally lower than in the following summer (June–August)” should be explained in more detail. Adequate information should be given about the importance of radiation flux and its relation to the subject.
Page 5 line 163
The name of the geological index in the expression “…the location of masked pixels in the images with a geological index…” should be specified.
Page 7 line 172
“There are a few areas that have relatively high index values ​​for both indices…”
This sentence should be explained in detail. Which of the two problems (multiple minerals and spectral mixing ) is more likely in the study? What effect did this study have on the results? How was this problem solved? Similar information should be mentioned in the text.
Page 7 line 180
The typo in the sentence "... index of Cudahy [16] in Fig. 2e." should be corrected as Fig.2f.
Page 8 line 190
The places of figure 3 and figure 4 in the manuscript should be in the corresponding sections on page eight. In addition, comments on the cause-effect relationship should be added to the findings given in Figure 3 in the section 3.3. Indices over time.
Page 8 line 220
“Looking at the dry periods in Fig4…”
it is seen that vegetation is high in dry periods 2 and 4 according to figure 4. Detailed information about this difference should be given and the reason should be explained.
Page 11 line 318
The relationship between variation and dry period mentioned in this sentence should be explained in more detail in the text.
Page 12 line 345
Detailed information should be given in the text about the reason why these bands were chosen as “Sentinel-2 MSI bands 2, 3, 4, 11 and 12”. For example; Are there indexes that are less affected by atmospheric effects and use different bands?
Author Response
Thank you for your review. Please find our response in the attached document (reviewer 2).
Author Response File: Author Response.pdf
Reviewer 3 Report
Review of the manuscript (article) titled How Weather Affects Over Time the Repeatability of Spectral Indices Used for Geological Remote Sensing
Below are some suggestions for improving your article.
· All references listed in References were cited in the text. However, some references should be completed or corrected.
o In line 455 should be added URL and day month year of accessing of URL.
o In references 24, 26 and 29, names of all authors are missing.
o In line 500 should be written https://doi.org/10.24381/cds.adbb2d47 (accessed on 20 January 2022) instead of Accessed 20 January 2022, https://doi.org/10.24381/cds.adbb2d47
o In lines 510, 512 and 518 should be written ESA. instead of (ESA), E.
o In lines 511, 513 and 519 should be added day of accessing of URL.
o In line 35 is written Hunt and Salisbury [8–10]. However, in references 8 and 9, the author is not only Salisbury, it should be corrected.
· In line 37 should be written MultiSpectral Scanner (MSS) instead of Multispectral Scanner (MSS).
· In line 45 should be written MultiSpectral Imagery (MSI) instead of Multi-Spectral Imager (MSI).
· In line 439 should be written MultiSpectral Imagery (MSI) instead of MultiSpectral Instrument (MSI).
· In line 75, it would be better if it is written The Google Earth Engine (GEE) [22] instead of The Google Earth Engine [GEE, 22].
· In lines 77 and 78, it would be better if it are written „Meteorological data was taken from the “global land data assimilation system (GLDAS 2.1)”, which comes at hourly intervals in 27.83 km grid cells [23,24].“ instead of „Meteorological data was taken from the “global land data assimilation system”, which comes at hourly intervals in 27.83 km grid cells. [GLDAS 2.1, 23,24].“
Author Response
Thank you for your review. Please find our response in the attached document (reviewer 3).
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The abstract has been rearranged to include the basic information of the article. In the abstract part, information about the results of the study is given. The importance and originality of the study is emphasized in the abstract. In the introduction, the originality of the study subject compared to the studies in the literature was emphasized. It is seen that the results obtained in the study are generally consistent among themselves. The contribution of the study to the literature is sufficiently emphasized in the discussion section. All corrections made in the Manuscript are sufficient for publication in the journal as such.
Congratulations,
