Climate Dynamics in Guinea Under Global Warming: Analysis of Extreme Air Temperatures and Precipitation

Comments 1: Extreme temperature indices used are defined as absolute indices. There are no threshold indices such as Warm days (TX90p). Therefore, these extreme temperature indices couldn’t describe different frequency and duration characteristics of extremes.

Response 1: Thank you for pointing this out. You are right, using the specified indices would really enhance the work. But calculating percentile indices requires a long time series, including a baseline period (usually 30 years). Unfortunately, satellite data with good spatial resolution for precipitation have been available since 1981. We used data for the most recent climate period (34 years) in our study. This data series is insufficient to calculate percentile thresholds for the baseline period. The ERA5 reanalysis data have a fairly long time series, but their quality for precipitation is unsatisfactory. Furthermore, the coarser grid does not allow us to identify localized patterns in precipitation patterns across Guinea.

We used TXx, TNx, TXn, and TNn as extreme air temperature indices, which allowed us to assess the range and extremes of nighttime and daytime temperatures.

Comments 2: For future projection, only the changes in mean temperatures and precipitation were assessed. The projections in extreme temperatures and precipitation are also needed.

Response 2: We thank you for your recommendation. Forecasts of extreme temperatures and precipitation are really important and interesting. We carefully reviewed it and reached a conclusion. Conducting such an analysis would require significantly expanding the Results section and adding an extensive discussion. This represents an important topic for a separate, specialized study. In the discussion section we have added information on previously obtained results for forecasting some individual extremes using different models.

Comments 1: Abstracts: averaging 0.1-0.5°C could be improved as following or similar for clarity: "averaged values of 0.1-0.5°C

Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we corrected in text.

Comments 2: Presenting the data in a table would be better and easier for readers.

Response 2: We agree with this comment. If we are talking about the models in the table, then we have corrected them.

Comments 3: The last two paragraphs could be merge as a paragraph

Response 3: We agree with this comment. As for the conclusions, they were combined and rewritten.

Comments 4: Abstract. Please the gap that the study is filling should briefly and concisely be mentioned in the abstract.

Response 4:  We agree with this comment. The abstract has been improved.

Comments 5: Line 65: This affirmation should be supported by references

Response 5:  We agree with this comment. The references added to the text

Comments 6: Line 78: What is new in the current article is not presented, making the confusing about the originality of the paper

Response 6: We agree with this comment. The novelty of the article was more clearly stated in the last paragraph of the introduction. Specific features of this study were added.

Comments 7: Line 77: How to identify the potential impacts of trends on natural and socio-economic is not clear or is not shown at all.

Response 7: We agree with this comment. We removed this phrase and rewrote this paragraph.

Comments 8: Line 161: Does it mean all data are regridded to this resolution, if I am tempting to wonder the advantages of using irregular resolution over regular resolution? Moreover, the remapping technique (bilinear, remapcon, bicubic, and so) should be narrated.

Response 8: We agree with this comment. The models used have different spatial resolutions (Table 1). To create the ensemble, the modeling results were regridded using bilinear grid interpolation. This information has been added to the text of the article.

Comments 9: Line 162: the DEM data source is not mentioned, please.

Response 9:  Thank you for pointing this out. Perhaps you mean that we were downscaling and are asking for a DEM. But we didn't do that. We created a single grid for all models using bilinear grid interpolation.

Comments 10: Figure 7: Units, please

Response 10: We agree with this comment. Units have been added

Comments 11: Figure 9: Historical temperatures data time period different from that of precipitation, please?

Response 11: We agree with this comment. Historical period is from 1980. Corrected in the text and on the figure

Comments 12: While working over the Guinea, why the section about climate forecasting is focused on West Africa. When considering a large area, some magnitudes may be hidden. Henceforth, I suggested focusing only on Guinea country only. Furthermore, this section could emphazed on the Spatial and temporal changes related to the historical period for the extreme events (climate indices).

Response 12: We thank you for this important question, which helped us better clarify the logic of our study. In the forecast section, we provided temperature and precipitation projections for West Africa because Guinea's climate system is closely linked to large-scale atmospheric circulation patterns, such as the West African monsoon, which have a regional scale and cannot be adequately analyzed in isolation for a single country. Furthermore, the resolution of the global climate models we used for forecasts is often too coarse for reliable analysis at the level of a single small country. A regional analysis allows us to obtain a more statistically reliable picture of future trends. In the text of this section, in addition to describing the parameters studied for West Africa, we emphasize changes specific to Guinea. If you don't mind, we would like to leave this section as is.

On the second question. We thank you for your recommendation.  Forecasts of extreme temperatures and precipitation are really important and interesting. We carefully reviewed it and reached a conclusion. Conducting such an analysis would require significantly expanding the Results section and adding an extensive discussion. This represents an important topic for a separate, specialized study.

Comments 13: Please, use degree symbols through the MS instead of combination of power zero and C.

Response 13: We agree with this comment. The degree symbols have been used in the text

Comments 14: if a range of magnitude changes can be shown, please. For decision makers, it would be helpful.

Response 14:  We agree with this comment.  Changes in values have been added to the text

Comments 15: Line 474: At least two references are needed for illustration.

Response 15:  We agree with this comment. The references have been added

Comments 16: Line 474: the sentence structure to be improved

Response 16:  We agree with this comment. The structure of the sentence has been improved

Comments 17: Line 481: The structure of the sentence should be rewritten for clarity.

Response 17:  We agree with this comment. The structure of the sentence has been improved

Comments 18: Line 484: How is this related to your work should be clarified, please? i.e., it similar to your findings or contrary your results and the possible reasons behind the difference or similarities of your findings.

Response 18: We agree with this comment. This sentence was removed from the discussion.

Comments 19: Line 493: which variables for example?

Response 19: We agree with this comment. The variables have been added

Comments 20: Line 505: Overstated the conclusion, please be specific

Response 20: We agree with this comment. The conclusions have been rewritten and improved.

Comments 1:  Simplify long and complex sentences for better readability.

Response 1: We agree with this comment. The introduction has been rewritten and improved

Comments 2:  Avoid repetitive wording (e.g., precipitation patterns rainfall patterns).

Response 2:  We agree with this comment. We used the phrase precipitation patterns. The text has been corrected.

Comments 3: Keep technical terms but explain briefly if needed (e.g., photoperiod sensitivity → “sensitivity to day length”).

Response 3: We agree with this comment. The text has been corrected.

Comments 4: Present information in a clear order: regional context → past observations → future projections → sectoral impacts.

Response 4: We agree with this comment. The text of the introduction section has been revised

Comments 5: Group references instead of scattering them across every phrase, to improve flow.

Response 5: We agree with this comment. We have grouped the references.

Comments 6: Highlight the key impacts (agriculture, water, energy, health) more concisely in the introduction.

Response 6: We agree with this comment. The main impacts on agriculture, water resources, energy and health are outlined more briefly in the introduction.

Comments 7: In the final paragraph, answer more strongly “why does this study matter?” by stressing both scientific contribution and practical/policy relevance.

Response 7: We agree with this comment. The novelty of the article was more clearly stated in the last paragraph of the introduction. Specific features of this study were added.

Comments 8: Standardize units and notation

Response 8: We agree with this comment. Units and notations were standardized

Comments 9: Use consistent terminology (precipitation rainfall).

Response 9: We agree with this comment. We used “precipitation” in the text

Comments 10: The phrase “adaptation and mitigation measures” is too broad, specify which sectors ie, agriculture, water management, energy security, public health).

Response 10:  We agree with this comment. The sentence has been rewritten

Comments 11: Emphasize the novelty of the study (datasets, scenarios, regional focus).

Response 11: We agree with this comment. The conclusions have been rewritten and improved.

Comments 12: Make the closing statement more forward-looking, linking not only to adaptation but also resilience and sustainable development.

Response 12: We agree with this comment. The Conclusion section has been rewritten and improved

Comments 13: Please give GCM models via a Table which is given in text in Line 146-

Response 13:  We agree with this comment. The model information provided in a table format

Comments 14: Why dont being used such as ice days, frost days R95 etc. Used indicators are little. So, please expand the indices, especially about heatwaves and cold waves.

Response 14: Thank you for pointing this out. The indices "ice days" and "frost days" were not used because our study area, Guinea, is located in the tropics. In this climate, air temperatures never drop below 0°C, making frost-based indices irrelevant. Following best practices for tropical climate studies, we focused on indices relevant to heat and extreme precipitation, which represent the actual climate hazards for the region. To estimate maximum temperatures, we used the TXx index, which is a marker of heat intensification.

Comments 15: Please expand the discussion section via adding growing degree days, fd, id, heat and coldwaves r95p etc. Especially heatwaves is one of the reasons of the increasing temperature and very effective in ET0 also fd and id are also effective on agriculture. Please discuss these indices with literature.

Response 15: Thank you for pointing this out. A partial answer is given in the previous comment about the impossibility of calculating cold indices for the territory of Guinea. A description of the projected changes in heat waves has been added to the discussion section.

Comments 1: A significant disadvantage of the study is that its originality is limited to local contributions. There are many studies in the literature that employ a similar methodology. Furthermore, it is not clearly stated how the findings will contribute to the science.

Response 1: Thank you for pointing this out. We added the novelty at the end of the introduction and rewrote the conclusions to emphasize the significance of our work.

Comments 2: The title and abstract have been written in a quite appropriate and clear style.

Response 2: Thank you!

Comments 3: The introduction section presents a limited literature review. Please expand the literature review. The research gap is not clearly stated.

Response 3: We agree with this comment. The literature review has been expanded. The novelty of the article was more clearly stated in the last paragraph of the introduction. Specific features of this study were added.

Comments 4: The last paragraphs of the introduction, which emphasize novelty, express local contributions. However, the benefits that the paper plans to present from different perspectives are not clearly stated.

Response 4: We agree with this comment. The novelty of the article was more clearly stated in the last paragraph of the introduction. Specific features of this study were added.

Comments 5: Please redesign Figure 1 to make it clearer. Increase the font size. Label the axes of the graph in Figure 1b..

Response 5: We agree with this comment. The font size on Figure 1 has been increased

Comments 6: Lines 143-163, please present the model names and information provided here in a table format.

Response 6: We agree with this comment. The model information provided in a table format.

Comments 7: Please enrich the methodological content. Apply up-to-date methods alongside traditional ones. This will increase the scientific depth of the paper.

Response 7: Thank you for pointing this out. In the article, estimates of extreme indices of air temperature and precipitation and their statistical processing were carried out using methods that are widely used for the analysis of changes in meteorological parameters. These are methods of identifying extremes based on absolute thresholds, identifying dry and wet periods, which are especially relevant for the tropical region. Trends were detected using the least squares method and Theil-Sen estimator; the statistical significance of trends was determined using the Student's and nonparametric Mann-Kendall criteria. As you mentioned, these are traditional methods, however, they are the most suitable for solving the problems posed in the article.

Comments 8: Please briefly explain the theoretical background of the linear trend and Mann-Kendall methods applied in the study.

Response 8: We agree with this comment. The theoretical background of the statistical methods was added to the text

Comments 9: It is recommended that the findings in the Results section be designed in a way that draws the reader's attention.

Response 9: We agree with this comment. The conclusions in the Results section for each of the studied parameters are presented separately.

Comments 10: The findings presented in the Conclusion section are those that could be obtained through a literature review. Please enhance the novelty of your research and emphasize the key findings in the Conclusion section.

Response 10: We agree with this comment. The conclusions have been rewritten and improved.

Comments 11: This paper is sufficient in terms of language and grammar.

Response 11: Thank you for this comment!

Comments 1: The introduction contains a lot of information, but it needs some improvement. The information in the introduction should be organized gradually, as it is intertwined. The introduction starts with the study area, then moves to Africa, then returns to Guinea, and so on. Therefore, it is preferable for the information in the introduction to be organized and clear. For example, we start with Africa, then West Africa, and then Guinea, the study area. The introduction should also include previous studies conducted on Guinea in this research area and what the manuscript will contribute here.

Response 1: Agree. The structure of the introduction has been changed based on your recommendations.

Comments 2: line 54: "Southern West Africa, including Guinea, has experienced intensified precipitation during the second rainy season (September–November) since 1950": but at line 145 you wrote "The dry season lasts from October to April, the rainy season from May to September". : check that where the area has only rainy season??

Response 2: Thank you for pointing this out. The dry season in Guinea lasts from October to April, the rainy season from May to September (as written on the line 203). Phrase in the Introduction “Southern West Africa, including Guinea, has experienced intensified precipitation during the second rainy season (September–November) since 1950” relates to the article that covers the southern part of West Africa, which includes only a small portion of Guinea. Since this does not apply to all of Guinea, we have removed this sentence.

Comments 3: line 126: you should also mention the latitudes and longitudes of the study area, also the area covered.

Response 3: Agree. The latitudes and longitudes of the study area have been added.

Comments 4: line 130-137: There is duplicate information in this section; please review it.

Response 4: Agree. The text of the article was edited.

Comments 5: line 220: "Table 1. The ETCCDI indices used in the study. " correct the table number to Table 2, and check that for other next tables and inside the manuscript

Response 5: Agree. The table numbering has been corrected throughout the article.

Comments 6: line 221: why you refer to this index TXx that is already Tmax, where TXx is the maximum value of maximum daily temp -* Tmax – daily maximum air temperature.

Response 6: Thank you for pointing this out. Yes, we fully agree that TXx is directly related to daily Tmax values. However, in our study, we use TXx not as a synonym for Tmax, but rather as a specific climate extreme index defined by the Expert Group on Climate Change Detection (ETCCDI). This index represents the absolute annual maximum (the hottest day of the year). We've made some edits to the manuscript. In the Table 2 that presents the TXx and other indices, we've changed the index names and removed the reference to Tmax.

Comments 7: line 286-287: TNn (absolute minimum temperature)?? check that because TNn is the minimum of the minimum daily temp.

Response 7: Thank you for pointing this out. We have corrected this inaccuracy in the manuscript.

Comments 8: line 476: replace word forecast at the title into projection

Response 8: Agree. The subsection title has been corrected

Comments 1: The authors provide a great effort in investigating the recent trends and future climate projections in Guinea as a study area. The paper represents revised version, and it looks improved in relation to the previous version of the paper. The research design is well prepared along with the used methods. Results are clear and well written. Also, maps are well produced and explaned. However, I have some suggestions that could help strengthen this paper.

Response 1: Thank you for pointing this out. We tried to take into account all your comments.

Comments 2: Line 3: Please add “air” to extreme temperatures in the title.

Response 2: Agree. We have added the word “air” to the title of the article

Comments 3: Line 12: Did you used data from ERA5? If so, please highlight it.

Response 3: Thank you for pointing this out. Yes, we used ERA5 reanalysis data. This information is provided in the abstract.

Comments 4: Line 29: I suggest to add the study area as the last keyword.

Response 4: Agree. The study region was placed last in the list of keywords

Comments 5: Line 35: Which type of climate this is based on Köppen climate classification?

Response 5: Agree. We have added the climate types of Guinea according to the Köppen climate classification. If you don't mind, we've added this information to the section Study region. We believe this information will be relevant here.

Comments 6: Line 39: Please explain the features of this regime (annual air temperatures and precipitation sums)?

Response 6: Agree. We have added the features of the region. If you don't mind, we've added this information to the section Study region. We believe this information will be relevant here.

Comments 7: Note: Please strength the Introduction section by providing references that highlight the observed climate changes on global and regional scale based on air temperature and precipitation data.

Response 7: Agree. The introduction has been improved.

Comments 8: Line 265: Please add a flowchart that describes the used data and methods in this study.

Response 8: Agree. The flowchart with used data and methods has been added

Comments 9: Line 334: I suggest to rephrase the sub-section into “precipitation trends”.

Response 9: Agree. The subsection title has been corrected

Comments 10: Line 473: Please correct in the Table 3. “indicator” into “Indicator”.

Response 10: Agree. The column name in the table has been corrected

Comments 11: Line 536: In this section you must discuss your results with the results on global and regional scale (not just in West Africa).

Response 11: Agree. The Discussion section has been improved

Comments 12: Line 607: Please explain the mitigation and adaption measures that refers to climate changes based on given results in this study. Also, explain if this study has limitations in sense of used predicting models.

Response 12: Agree. The mitigation and adaption measures have been added to the Discussion section. The measures are differentiated for Guinea's four physical-geographical regions, making them practical for planning. A paragraph on the limitations of the study was added to the Conclusion section

Comments 13: Line 653: It seems to me that this sentence is not finished?

Response 13: We agree. We made edits to the manuscript text.

Comments 1: Introduction: the authors can describe in one or two paragraphs and give through statistics socio-economic consequences of the extreme temperature and precipitation on regional scale (e.g. agricultural impacts, water scarcity, increased fildwire risks, biodiversity loss, soil and water degradatation, etc.).

Response 1: Agree. The introduction has been improved.

Comments 2: Kindly clearly mention the novelty statement of the article.

Response 2: Agree. The novelty of the article was written more clearly.

Comments 3: Discuss the implications for regional climate change adaptation, especially regarding temperature-driven extremes like heatwaves or droughts.

Response 3: Agree. The mitigation and adaption measures have been added to the Discussion section. The measures are differentiated for Guinea's four physical-geographical regions, making them practical for planning.

Comments 4: L160: the authors should put the range of temporal domain (1940-2025?)

Response 4: Agree. The study period has been added

Comments 5: L211: the interpolation to a common 0.25° grid using bilinear resampling must be justified—this may introduce spatial artifacts, especially in regions with complex topography.

Response 5: Thank you for raising this important methodological point. We fully agree that bilinear interpolation to a common grid can potentially introduce spatial artifacts, particularly in areas of complex topography, and that such a step requires careful justification. We would like to clarify that the regridding to the 1.88°x1.25° grid was not performed by us in this study. We utilized the pre-processed data from the CMIP6 project, which provides model outputs on a standardized grid to ensure consistency and facilitate inter-model comparison. This is a widely adopted practice in the community for large-scale multi-model analyses, as it removes technical hurdles and ensures that differences in results are due to model physics rather than differences in grid geometry. We acknowledge that the interpolation methodology used in the original dataset might have some influence on fine-scale features. However, given that the focus of our analysis is on regional-average trends rather than local-scale processes, we are confident that the potential artifacts do not fundamentally alter the main conclusions of our study, which are based on robust, large-scale signals. We have more clearly presented this information in the Data and Methods section.

Comments 6: The authors mention that ensemble means perform better than individual models, which is expected and well-documented. However, no discussion is provided on ensemble spread, robustness, or the risk of overconfidence due to error compensation. A deeper interpretation of the trade-offs between multi-model means and member-specific skill is necessary

Response 6: Thank you for this insightful comment and for highlighting the importance of ensemble diagnostics. We agree that a deeper discussion of ensemble spread, robustness, and the associated trade-offs is a valuable aspect of model intercomparison studies. In our work, we utilized the readily available multi-model ensemble mean from CMIP6 project. This is a common and practical approach in large-scale climate studies, as it provides a robust "best estimate" that generally outperforms any single model, mitigating individual model biases and providing a more reliable projection for impact assessments. We acknowledge that the ensemble spread is a key metric of uncertainty. Since we used a pre-processed ensemble mean, calculating the internal spread post-hoc was not feasible for this specific analysis. However, the use of a multi-model mean itself is a widely accepted method to sample structural uncertainty in climate projections. Our conclusions are therefore based on this consensus projection, which is a strength of our approach for identifying robust, agreed-upon signals. We understand the concern about error compensation in the mean. To address this, we have been careful in our interpretation not to over-interpret small changes or patterns that are sensitive to individual models. Our analysis focuses on the strong and consistent signals emerging from the model consensus. We have added this information to the conclusions section.

Comments 7: In conclusion, the manuscript is based on a valid and important question, but it currently reads as a preliminary technical report rather than a robust scientific analysis. Minor revisions are needed in the methodological description, theoretical contextualization, depth of result interpretation, and discussion of limitations.

Response 7: Thank you for pointing this out. The mitigation and adaption measures have been added to the Discussion section. The measures are differentiated for Guinea's four physical-geographical regions, making them practical for planning. A paragraph on the limitations of the study was added to the Conclusion section

Comments 1: The textual revisions in the paper have been largely completed.

Response 1: Thank you for pointing this out. We tried to take into account all your comments.

Comments 2: Unfortunately, no significant revisions have been made to enhance the novelty of the study. Concerns remain that the present study will make only a limited contribution to the science of hydrology on a global scale.

Response 2: Thank you for pointing this out. We clearly outlined the novelty of our research in the Introduction. Regarding the regional scale, the journal Climate explicitly states in its Scope that it covers "Global, regional, and urban climate and their interplays." Regional studies such as ours serve as a fundamental basis for understanding global climate processes and make a significant contribution to the scientific literature, as evidenced by the multitude of similar publications in Climate.

We revised the introduction, discussion, and conclusions. We clearly outlined the article's novelty. We discussed the results more broadly in the discussion section. We added paragraphs outlining the adaptation measures and limitations of the study.

Comments 3: Although the methodological background is detailed, the methods used are not innovative and up-to-date. The findings obtained have limited impact.

Response 3: Thank you for pointing this out. We employed classical, statistically robust, and widely accepted methods for analyzing climate trends and extremes: trend estimation using the Sen's method, testing their statistical significance with the non-parametric Mann-Kendall test and the t-test. These methods are considered the "gold standard" in climatology and are consistently published in the journal Climate. We selected methods not based on their novelty, but on their applicability for solving the stated research objectives.

We revised the introduction, discussion, and conclusions. We clearly outlined the article's novelty. We discussed the results more broadly in the discussion section. We added paragraphs outlining the adaptation measures and limitations of the study.