Temporal and Spatial Analyses of Forest Burnt Area in the Middle Volga Region Based on Satellite Imagery and Climatic Factors

Round 1

Reviewer 1 Report

In this work the authors present their analysis on burned area patterns over a large area in the Russian Federation for a period of 20 years. Their methods are based on the use of web-based platforms like GEE and satellite derived data and products. It is quite interesting due to the location these fires are recorded, not a typical fire-prone landscape, therefore consideration of climate-driven fire occurrence could provide further insight on the subject. In addition, the use of modern tools like the LandTrendR algorithm for analyzing large data volumes of satellite imagery provides new opportunities in areas of research like forest fires.

The manuscript has a good structure, it is easy for the reader to follow, and overall, the quality of presentation is satisfactory. I would like, on the other, hand to raise some questions on the research design, that if clarified can further improve its quality.

·    I think the authors should emphasize more on the advantages of using GEE based algorithms for mapping disturbances, fires, for this analysis over the MODIS standard products for instance. MODIS BA could be used alone for large-scale analysis and comparison with climatic data.

· How exactly MODIS data are used? Lines 157-163 mention the discrimination of fire areas from other disturbances but I am rather confused. This is prior to LT application? Was MODIS used as reference, or as comparison with Landsat derived results? Usually, Landsat is used for validating lower resolution products.

·   So, when in the discussion the authors mention (lines 438-430) that Landsat BA was found more than MODIS this means that a comparison was made. And this is not presented in detail in the results. I think the role of MODIS data in this study should be clarified and displayed. For example, if the smaller than 25ha fires were not considered,  to what degree this would affect the final results.

·       Was there a mask created over forest land for running LT algorithm? This is a forest-oriented application and does not perform well in agricultural land. Moreover, the LT results are aggregated at yearly step with no other time information, as far as I am aware. When the authors present the comparison of climatic factors with the BA at monthly time step, it means the Landsat BA was derived per month of the year?

·   For the accuracy assessment, could the authors clarify the proportion-based comparison at pixel level? They could include a general table-confusion matrix in the main text and omit figure 5 for example. This figure does not add to the discussion.

·      In 2.2.3, lines 219-222. It is not very clear how the filtering was applied. Pre and post fire difference was based on dNBR? You mention 3 positive NBR values during each year but I am not sure what this means.

·   Finally, the flowchart should have connectors with the general objectives, now it is just a break down of tasks and does not state the research goals.

Quality of English is ok, minor corrections needed.

Author Response

Please see the attachement.

Author Response File: Author Response.pdf

Reviewer 2 Report

This manuscript aims to investigate the temporal and spatial characteristics of burnt areas in the Middle Volga region. The conceptual foundation of this article is well-conceived; however, certain aspects and apparent errors need to be addressed to allow for a more comprehensive understanding of the results and to streamline the review process. I recommend a major revision.

Some identified errors include:

Line 103: Please provide the latitude/longitude range of the study region. Correct and clarify as needed.

Line 154: Ensure the accuracy of the path/row number.

Line 181: Specify the unit of precipitation used for later analysis.

Figure 5: Add a colorbar for clarity.

Figure 6: (a) Clarify how cumulative burnt area is calculated. It appears the figure depicts burnt area for each year. (b) Explain the rationale for excluding the year 2010 in poly fitting. Do you believe poly fitting is an appropriate approach?

Additionally, please correct all format errors in numerical values throughout the manuscript.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

I have carefully reviewed your manuscript titled "Temporal and spatial analyses of forest burnt area in the Middle Volga region based on satellite imagery and climatic factors." I commend you on the extensive work undertaken to analyze the spatiotemporal patterns of burnt areas and their correlation with climatic factors in the Middle Volga region. The research is of great importance, particularly in understanding the impact of wildfires on forest dynamics and ecosystem services.

However, I believe the manuscript requires major revisions before it can be considered for publication. I have outlined several specific concerns and suggestions below:

1. Clarity and Structure:

   • The introduction could benefit from providing a clearer background on the significance of studying forest burnt areas, particularly in the Middle Volga region. Additionally, a brief overview of previous research in the field would be helpful.
   • The methodology section lacks detail on the specific procedures and parameters used in the analyses. Providing a more comprehensive description, including the rationale behind the chosen methods, will enhance the reproducibility of your study.

2. Data and Analysis:

   • Clarify the satellite imagery sources and sensors used in your analysis. Specify the bands or wavelengths employed and explain how they contribute to the accuracy of your results.
   • In the temporal trend analysis, provide more information on why the Mann-Kendall test and Theil-Sen’s slope estimator were chosen, and how the LandTrendr algorithm integrates with Google Earth Platform.
   • Include a discussion on potential limitations and uncertainties associated with remote sensing time series analysis in forest fire detection.

3. Results and Discussion:

   • Present the results in a more structured and reader-friendly format. Use clear headings and subheadings to guide the reader through the key findings.
   • Elaborate on the ecological implications of the observed spatiotemporal patterns. What do the irregular fire occurrences mean for forest regeneration and ecosystem services in the Middle Volga region?

4. Accuracy Assessment:

   • Provide additional details on the 581 test sites used in the accuracy assessment. Were they randomly selected? What criteria were applied to choose these specific sites?

5. Conclusions:

   • The conclusion section should provide a concise summary of the main findings and their implications. Highlight how your research contributes to the existing body of knowledge on wildfires and forest dynamics.

6. Language and Style:

   • The manuscript would benefit from professional proofreading to ensure clarity and coherence in writing.

In conclusion, your research has the potential to make a significant contribution to the field of forest fire dynamics. Addressing the above concerns will enhance the overall quality and impact of your manuscript. I look forward to reviewing the revised version.

Moderate editing of English language required

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors appear to have made required corrections, thus clarifying my concerns, though not all of them.

Author Response

Dear reviewer, we would like to express our gratitude once more for your valuable comments and suggestions.

Reviewer 2 Report

The authors have made some corrections to the manuscript as per my previous suggestions, but there are still numerous formatting errors present. The methodology is not clear enough to understand the results. I recommend major revision.

For instance, in Figure 8, there is inconsistency in the representation of float numbers, with some using "." as a decimal separator and others using ",". Additionally, it is customary in research to employ the color scheme of blue-white-red to denote correlation levels. Therefore, the use of blue-green-red to display correlation results, especially with non-significant correlations appearing in a strong green color, appears unconventional and might lead to confusion. Consider revising the color scheme; using blue for negative correlations, red for positive correlations, with significant correlations highlighted in bold, and insignificant ones in black.

The authors need adding more detailed information to the methodology section to understand the results.

In Figure 7, which illustrates correlations for each pixel, it would be helpful to clarify which pixels exhibit significant correlations. Do these results include data from the year 2010?

Regarding the Table 2, could you please provide details on how the numbers were derived? Were the variables area-averaged first and then calculated correlation, or were the correlation is the average of correlation of each pixel? Additionally, I suggest adjusting the format of the float numbers in this table for consistency.

Furthermore, regarding the establishment of the multi-regression equation, could you elaborate on the methodology? Was it determined by averaging correlations or by employing polynomial fitting on the area-averaged variables? Additionally, clarification is needed on how May to September data were utilized.

Author Response

Dear reviewer, we sincerely appreciate the time you dedicated to reviewing our manuscript and providing additional valuable suggestions for its improvement. Please find the responses in the attached file.

Author Response File: Author Response.pdf

Reviewer 3 Report

Since the authors have revised the manuscript as per the suggested comments, the manuscript may be accepted for publication.

Author Response

Dear reviewer, we would like to express our gratitude once more for your valuable comments and suggestions.

Round 3

Reviewer 2 Report

The authors have responded to my questions appropriately. I recommend accepting the manuscript. Congratulations!