Assessment of Meteorological Drought Trends in a Selected Coastal Basin Area in Poland—A Case Study

Round 1

Reviewer 1 Report

The article deals with the important issue of assessing drought and its changes. The authors presented one of the catchment areas in northern Poland. The article is based on standard methods of drought assessment and also such an approach (statistics) in assessing long-term changes. The article, because it deals with meteorological drought, is suitable for the journal Climate (MDPI). In its current form, it does not bring new content to water science and, in my opinion, is not eligible for publication in the journal Water.

Specific comments:

Much of the Introduction relates to the description of SPI. This should be done in the Methods chapter. Here, the focus should be on a review of the literature in relation to meteorological droughts, what are the gaps in this area, what are the latest research trends. How does the current article fit into the whole against this background.

Line 78-81 The selection of the catchment area requires details. Is it representative of the entire Baltic Sea coast?

Horizontal precipitation is an important element - especially in winter. I do not find information on how parameters such as dew, glaze, rime or frost were evaluated.

The authors analyze the flow of the river Leba, but only in the methodological part (Study area). There is no relation between the obtained results and this parameter.

The data do not include the last period (2016-2022), which is very interesting from the point of view of the analysis, among other things, due to the occurrence of extreme weather events.

The Discussion and Conclusions layout is not very readable. As a reader, I expect clearly collated information about the greatest achievement of the research conducted and also the limitations.

Author Response

Dear Reviewer 1

We sincerely thank you for reviewing our paper submitted to Water. We are grateful for a thorough and constructive review. We did our best to carefully consider all comments and to improve the manuscript according to given suggestions. Attached below, please find our point-by-point responses to all your comments:

The article deals with the important issue of assessing drought and its changes. The authors presented one of the catchment areas in northern Poland. The article is based on standard methods of drought assessment and also such an approach (statistics) in assessing long-term changes. The article, because it deals with meteorological drought, is suitable for the journal Climate (MDPI). In its current form, it does not bring new content to water science and, in my opinion, is not eligible for publication in the journal Water.

- Meteorological droughts are the first stage of drought and affect water resources. They are important to the local community and water managers. The article is a preliminary study to show research gaps and determine further detailed research on the impact of meteorological droughts on water resources.

Specific comments:

Much of the Introduction relates to the description of SPI. This should be done in the Methods chapter. Here, the focus should be on a review of the literature in relation to meteorological droughts, what are the gaps in this area, what are the latest research trends. How does the current article fit into the whole against this background.

-We moved some information to methods. The article concerns meteorological droughts, so it was important for us to indicate one of the most popular indicators used to monitor meteorological drought. The obtained results did not give a clear answer, hence detailed research will be undertaken at a later stage

Line 78-81 The selection of the catchment area requires details. Is it representative of the entire Baltic Sea coast?

-The research proposed by us is the first research of this type in the coastal catchment in local terms. So far, regional studies have only used data for the Łeba meteorological station, which characterized the entire coastal area. In terms of geology and morphology, the analyzed catchment is representative of the young glacial area of north-western Poland. However, it is varied in terms of height, which affects the local differentiation of the water cycle. In terms of climatic conditions, the catchment represents the central and eastern parts of the coast and the lake district. We have added short information in the text. Generally, at this stage, it is difficult to indicate whether the studied catchment as a whole is representative for the entire southern coast of the Baltic Sea, hence the motivation to conduct further research.

Horizontal precipitation is an important element - especially in winter. I do not find information on how parameters such as dew, glaze, rime or frost were evaluated.

- The SPI index includes only precipitations, which is recorded with an accuracy of 0.1 mm. The study uses the measurement data of precipitation sums, without distinguishing between atmospheric sediments as a source of water. Observational data of meteorological phenomena from such a long period are difficult to obtain. In addition, the role of horizontal precipitation in the study area is less significant compared to the rest of Poland, especially mountainous areas, which may be indicated, for example, by the average number of days with rime, which at the stations in Łeba and Lębork does not exceed 5 days a year and is one of the lowest in Poland [IMGW PIB https://imgw.isok.gov.pl/mapy-klimaticzne/szadz.html].

The authors analyze the flow of the river Leba, but only in the methodological part (Study area). There is no relation between the obtained results and this parameter.

- The flows of the Łeba River are one of the elements describing the hydrological conditions. Periods of low average annual flows coincide with periods of meteorological drought. We have added the relevant entry to the article.

The data do not include the last period (2016-2022), which is very interesting from the point of view of the analysis, among other things, due to the occurrence of extreme weather events.

- The paper presents preliminary research, which is the beginning of a broader analysis of the occurrence of meteorological and hydrological drought in the entire area of north-western Poland until 2023.

The Discussion and Conclusions layout is not very readable. As a reader, I expect clearly collated information about the greatest achievement of the research conducted and also the limitations.

- We fixed it. We separated discussions and conclusions

Kind regards

Katarzyna Kubiak-Wójcicka

Małgorzata Owczarek

Izabela Chlost

Alicja Olszewska

Patrik Nagy

Author Response File: Author Response.docx

Reviewer 2 Report

The study is interesting. However, many improvements are needed before accepting it.

Abstract needs to cover the overall novelty and contribution of the study.

Introduction is not sufficient, the authors are advised to refer to : Spatiotemporal variability analysis of standardized precipitation indexed droughts using wavelet transform.  And Rainfall Variability Index (RVI) analysis of dry spells in Malaysia

The limitations of the study should be reported.

“Figure 6. Long-term variability….”, please mention a,b and c

More discussion is needed, the authors reported the findings without giving justifications.

Discussion and conclusions: Please split the discussion from conclusion 

Author Response

Review 2

Dear Reviewer 2

We sincerely thank you for reviewing our paper submitted to Water. We are grateful for a thorough and constructive review. We did our best to carefully consider all comments and to improve the manuscript according to given suggestions. Attached below, please find our point-by-point responses to all your comments:

The study is interesting. However, many improvements are needed before accepting it.

Abstract needs to cover the overall novelty and contribution of the study.

• We corrected the abstract.

Introduction is not sufficient, the authors are advised to refer to : Spatiotemporal variability analysis of standardized precipitation indexed droughts using wavelet transform.  And Rainfall Variability Index (RVI) analysis of dry spells in Malaysia

• We revised the introduction and added new literature

The limitations of the study should be reported.

• We added in the paper

“Figure 6. Long-term variability….”, please mention a,b and c

• We put signatures a, b, c

More discussion is needed, the authors reported the findings without giving justifications.

Discussion and conclusions: Please split the discussion from conclusion 

 - We completed the discussion and divided the discussion and conclusions separately

Kind regards

Katarzyna Kubiak-Wójcicka

Małgorzata Owczarek

Izabela Chlost

Alicja Olszewska

Patrik Nagy

Author Response File: Author Response.docx

Reviewer 3 Report

The paper titled ‘Assessment of meteorological drought trends in a selected coastal basin area in Poland - a case study ‘ presents the results of a study of atmospheric precipitation conditions in light of meteorological drought occurrence in the northern part of Poland in the area of Łeba River catchment. The Authors analysed drought spell occurrence based on the Standardized Precipitation Index.

1. The abstract is informative and coherent.

2. The Introduction provides essential and up-to-date information related to the topic. Most of the references were published during the last few years.

3. The results of the study are representative of the area of the Łeba catchment area since the meteorological data were derived from 7 meteorological stations located within this area and the data series are of the 60-year period.

4. The section on Materials and Methods contains all the necessary information, however, the section on Discussion needs to be deepened.

Specific comments:

L 122. The area is provided firstly in hectares, then in km2. I suggest unifying the units being used.

Figure 4 is rather low quality. Is it possible to insert into the manuscript a higher resolution map?

In Figure 8. there is: 'Total duration of drought in % a analysed...  ' shouldn't be : 'Total duration of drought in % of analysed....'

L. 364 In the sentence it should be indicated that the mentioned trends were negative/downward

Table 7 There is a lack of a table footer.

L 451. It seems to me, that something is missing in the sentence. Please the Authors to rewrite this sentence.

Overall, in my opinion, the manuscript brings essential knowledge regarding the field of hydrometeorology in the area of northern part of Poland in the area of Łeba River catchment, therefore after some improvements I do recommend it be published in the journal of Water.

Author Response

Review 3

We sincerely thank you for reviewing our paper submitted to Water. We are grateful for a thorough and constructive review. We did our best to carefully consider all comments and to improve the manuscript according to given suggestions. Attached below, please find our point-by-point responses to all your comments:

The paper titled ‘Assessment of meteorological drought trends in a selected coastal basin area in Poland - a case study ‘ presents the results of a study of atmospheric precipitation conditions in light of meteorological drought occurrence in the northern part of Poland in the area of Łeba River catchment. The Authors analysed drought spell occurrence based on the Standardized Precipitation Index.

1. The abstract is informative and coherent.
2. The Introduction provides essential and up-to-date information related to the topic. Most of the references were published during the last few years.
3. The results of the study are representative of the area of the Łeba catchment area since the meteorological data were derived from 7 meteorological stations located within this area and the data series are of the 60-year period.
4. The section on Materials and Methods contains all the necessary information, however, the section on Discussion needs to be deepened.

Specific comments:

L 122. The area is provided firstly in hectares, then in km2. I suggest unifying the units being used.

• We corrected.

Figure 4 is rather low quality. Is it possible to insert into the manuscript a higher resolution map?

• We corrected. We set the map with a larger size.

In Figure 8. there is: 'Total duration of drought in % a analysed...  ' shouldn't be : 'Total duration of drought in % of analysed....'

• We corrected.

1. 364 In the sentence it should be indicated that the mentioned trends were negative/downward

- We have refined the information.

Table 7 There is a lack of a table footer.

• We set the footer.

L 451. It seems to me, that something is missing in the sentence. Please the Authors to rewrite this sentence.

• We corrected.

Overall, in my opinion, the manuscript brings essential knowledge regarding the field of hydrometeorology in the area of northern part of Poland in the area of Łeba River catchment, therefore after some improvements I do recommend it be published in the journal of Water.

Author Response File: Author Response.docx

Reviewer 4 Report

Drought is one of the most destructive hydrological hazards effecting the human life directly. Therefore, it is important to analyze the previous or present droughts to minimize the effects of it. As the authors mentioned in their study, Standardized Precipitation Index (SPI) was widely used in recent studies to understand the drought variability. Also, this approach was recommended by the World Meteorological Organization (WMO).

Even the method itself is not novel and it was already tested in many areas, It always has an importance to test it under different climatic conditions as the authors underlined that point. Shortly, I agree with the authors it is going to make a difference to utilize SPI in smaller catchments.

It seen that most parts of the manuscript was already changed and improved.

I have following suggestions for the authors;

Line 153-155: The sentence “The even distribution of runoff in different time scales, despite the prevailing varied hydrometeorological conditions, is the result of the dominant share of underground supply in the total runoff.” Is too long. It is hard to understand the meaning of it. I suggest to re-write it.

Line 160: It would be better adding the explanation of SQ and SSQ under the figure 2.

Line 172: I suggest adding a column to the Table 2 to show the standard deviation of the Average annual precipitation in years 1956-2015. It will be helpful for readers to understand how it varies over years.

Line 180: “….even they are not complete” The authors must explain what they mean in this sentence. What is the approach if the time series are not complete ?

Line 267-Line 293: I suggest adding a description of the trend coefficients at the end of the Tables. A brief description of how it was calculated..

Line 375: The title is discussion and conclusions, however there is one another title named as “conclusion”. I suggest removing the title discussion and conclusions. It would be better to add the discussion section at the end of the results section. And the discussion section can be briefer.

Author Response

Review 4

We sincerely thank you for reviewing our paper submitted to Water. We are grateful for a thorough and constructive review. We did our best to carefully consider all comments and to improve the manuscript according to given suggestions. Attached below, please find our point-by-point responses to all your comments:

Drought is one of the most destructive hydrological hazards effecting the human life directly. Therefore, it is important to analyze the previous or present droughts to minimize the effects of it. As the authors mentioned in their study, Standardized Precipitation Index (SPI) was widely used in recent studies to understand the drought variability. Also, this approach was recommended by the World Meteorological Organization (WMO).

Even the method itself is not novel and it was already tested in many areas, It always has an importance to test it under different climatic conditions as the authors underlined that point. Shortly, I agree with the authors it is going to make a difference to utilize SPI in smaller catchments.

It seen that most parts of the manuscript was already changed and improved.

I have following suggestions for the authors;

Line 153-155: The sentence “The even distribution of runoff in different time scales, despite the prevailing varied hydrometeorological conditions, is the result of the dominant share of underground supply in the total runoff.” Is too long. It is hard to understand the meaning of it. I suggest to re-write it.

• We corrected

Line 160: It would be better adding the explanation of SQ and SSQ under the figure 2.

• We added explanations

Line 172: I suggest adding a column to the Table 2 to show the standard deviation of the Average annual precipitation in years 1956-2015. It will be helpful for readers to understand how it varies over years.

• We added.

Line 180: “….even they are not complete” The authors must explain what they mean in this sentence. What is the approach if the time series are not complete ?

• We corrected

Line 267-Line 293: I suggest adding a description of the trend coefficients at the end of the Tables. A brief description of how it was calculated..

• The linear trend coefficients were determined with MS Excel using the least squares method according to the formula:

t_i    - values of independent variable (time – years in sequence)

Y_i  - values of dependent variable (precipitation sum) in the i-period

   -  mean value of  t

  - mean value of  Y

Line 375: The title is discussion and conclusions, however there is one another title named as “conclusion”. I suggest removing the title discussion and conclusions. It would be better to add the discussion section at the end of the results section. And the discussion section can be briefer.

- We corrected

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Thank you for the answers and corrections provided.

Unfortunately, they do not convince me enough to recommend the article for publication in the journal Water.

The main objection has not been corrected. So, it is still analyzed meteorological (not hydrological or hydrogeological) drought, which thematically fit the profile of other journals from the MDPI publishing house (e.g. Climate).

Still there is no detailed specificity of catchment selection. What is the direct effect of the sea on parameters such as humidity, wind and, consequently, rainfall?

I am not convinced by the statement that the period 1956-2015 is a preliminary study, and that adding the next few years will already be a detailed study. If there is data up to 2022 (and I assume there is) then it should be used without question.

Author Response

Review 1

Thank you for the answers and corrections provided.

Unfortunately, they do not convince me enough to recommend the article for publication in the journal Water.

The main objection has not been corrected. So, it is still analyzed meteorological (not hydrological or hydrogeological) drought, which thematically fit the profile of other journals from the MDPI publishing house (e.g. Climate).

• Precipitation is a basic component of the water cycle, so we cannot agree with the reviewer's opinion that the subject of our paper does not fit the profile of Water journal.

Still there is no detailed specificity of catchment selection. What is the direct effect of the sea on parameters such as humidity, wind and, consequently, rainfall?

• In our opinion, demonstrating the direct influence of the sea on the above-mentioned meteorological elements in the area of the studied catchment would require their more detailed seasonal analysis. The work analyzes the differences in air temperature, pointing to the thermals of the Baltic Sea waters as one of the factors shaping the thermal conditions in the coastal area. Based on the results obtained in the study, it can be concluded that in the case of the analyzed precipitation sums at all analyzed stations, the highest precipitation sums occur in summer, and autumn precipitation is higher than in spring, which is characteristic of coastal areas.

​

I am not convinced by the statement that the period 1956-2015 is a preliminary study, and that adding the next few years will already be a detailed study. If there is data up to 2022 (and I assume there is) then it should be used without question.

• We agree that including the period up to 2022 would be beneficial and possible.Despite this, we still believe that the period of 60 years to 2015 is sufficient for the first analysis of the occurrence of drought in the studied catchment.

Author Response File: Author Response.docx