Connected Variations of Meteorological and Electrical Quantities of Surface Atmosphere under the Influence of Heavy Rain

Round 1

Reviewer 1 Report

I believe my comments have been sufficiently accounted for and the article can be accepted. However, I suggest a couple of minor typographical amendments just to make things clearer

 

1. line 142, 87% and 13% should be swapped around, otherwise the interpretation is that intramass showers produce negative conductivity increases in 87% of cases.
2. the use of "÷" to denote ranges of values can be confused with division, maybe the long dash would work better? For the editorial team to decide.

Author Response

Responses on comments of the reviewer 1

 

# Abstract

1) Comment of the reviewer: line 142, 87% and 13% should be swapped around, otherwise the interpretation is that intramass showers produce negative conductivity increases in 87% of cases.

Response: The 87% and 13% were swapped around (line 144).

 

2) Comment of the reviewer: the use of "÷" to denote ranges of values can be confused with division, maybe the long dash would work better? For the editorial team to decide.

Response: The "÷" symbols have been replaced with the "–" symbols (lines 115 and 207, Table 1).

Author Response File: Author Response.doc

Reviewer 2 Report

The study of an effect in near-surface atmospheric electricity during rainfall and different synoptic conditions corresponds to the scope of the journal and will be interesting to readers. It is recommended to publish the manuscript in “Atmosphere” after minor revision.

The authors have improved the manuscript based on previous suggestions. The abstract and the description of observations have become more detailed. However, a minor revision is required.

Notes:

• Line 131: Please cite the references for explanation of the threshold of 5 mm/h – [43] and [33].
• Line 136: It is good that the quantitative value of increase was added in “Results” and “Table A1”. I see no need for percentage values though; the ratio (or maybe dB) values seem to be enough. However, if the authors consider the percentages to be an appropriate description of increase, so be it.
  Also here, “…vs normal values” should be replaced by “undisturbed values”. It would be great if the authors also clarify the time interval that was used for calculation of undisturbed values. Because one can note on fig. 3 and 4 that the “normal values” might be different for each event (about 6x10^-15 and 2x10^-15 S/m).
• Fig. 3 and 4: I don’t understand why all the arrows have been removed from fig. 4 and text (lines 162-167). If it was not important then everything is fine. However, I asked about the arrows 1-4 in fig. 3b. The arrows 5-8 are mentioned in the text, but the arrows 1-4 are not. Please include the explanation on the arrows 1-4 (fig. 3) in the text or delete it and change the arrows numbers.

Author Response

Responses on comments of the reviewer 2

 

1) Comment of the reviewer: Line 131: Please cite the references for explanation of the threshold of 5 mm/h – [43] and [33].

Response: These references was cited in the text (line 131).

 

2) Comment of the reviewer: Line 136: It is good that the quantitative value of increase was added in “Results” and “Table A1”. I see no need for percentage values though; the ratio (or maybe dB) values seem to be enough. However, if the authors consider the percentages to be an appropriate description of increase, so be it. Also here, “…vs normal values” should be replaced by “undisturbed values”. It would be great if the authors also clarify the time interval that was used for calculation of undisturbed values. Because one can note on fig. 3 and 4 that the “normal values” might be different for each event (about 6x10-15 and 2x10-15 S/m).

Response: We consider the percentages to be an appropriate description of the increase. The phrase “… vs normal values” was changed to “undisturbed values” (line 136). To estimate the undisturbed values for each case, the 10 minute interval preceding the passage of Cb and precipitation was used. This clarification was added to article (lines 137–138).

 

3) Comment of the reviewer: Fig. 3 and 4: I don’t understand why all the arrows have been removed from fig. 4 and text (lines 162-167). If it was not important then everything is fine. However, I asked about the arrows 1-4 in fig. 3b. The arrows 5-8 are mentioned in the text, but the arrows 1-4 are not. Please include the explanation on the arrows 1-4 (fig. 3) in the text or delete it and change the arrows numbers.

Response: The necessary changes were made (lines 154, 156, 157, 160 and 163, Figure 3)

Author Response File: Author Response.doc

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Observations of meteorological and atmospheric electricity parameters from the area around GO IMCES in Tomsk are presented in this study. The measurements include:

* precipitation intensity from a Vaisala RAINCAP sensor
* droplet diameter from an optical disdrometer OPTIOS
* polar electrical conductivity from an instrument called "Electroconductivity-2"
* electric field from field mills "Field-2" and CS100/CS110
* weather station and satellite data

The precipitation intensity data is used to identify periods of heavy rainfall > 5 mm/h. Weather station and satellite information are used to differentiate the heavy rainfall events by synoptic conditions like frontal storms or air mass showers. It was found that frontal storms tend to be coincide with a strong, almost instantaneous increase in negative conductivity, but this signal is not present in air mass showers.

A detailed case study of a frontal storm event and a air mass shower event is also presented to show that frontal storms and air mass shower events differ by their potential gradient signal and also the droplet size distribution.

The study is novel, linking synoptic conditions, droplet size distribution and potential gradient to conductivity with what looks like a reasonable dataset. There are some issues about the dataset that need clarification, i.e. description of instruments and methodology details, data presentation - please see more granular comments below.

# Abstract

* The abstract is vague and does not draw the reader in, below are some suggestions to improve it.
* Please expand on the motivation / impact of research
* Concluding statement can be more specific -> rain associated with frontal Cb produces a sharper change in atmospheric negative electrical conductivity than air mass showers
* Why is the conclusion on droplet size (lines 166--168) not mentioned?
* Briefly describe methodology / novelty

# Intro

* Air conductivity is dependent on air ions so work in atmospheric air ions must be considered here. See for e.g.

A. Hirsikko et al., ‘Atmospheric Ions and Nucleation: A Review of Observations’, Atmospheric Chemistry and Physics 11, no. 2 (26 January 2011): 767–98, https://0-doi-org.brum.beds.ac.uk/10.5194/acp-11-767-2011.

and references therein.

* Please mention previous work on rainfall and ion production, for e.g.

A. K. Kamra, A. S. Gautam, and Devendraa Siingh, ‘Charged Nanoparticles Produced by Splashing of Raindrops’, Journal of Geophysical Research: Atmospheres 120, no. 13 (2015): 6669–81, https://0-doi-org.brum.beds.ac.uk/10.1002/2015JD023320.

H. Tammet, U. Hõrrak, and M. Kulmala, ‘Negatively Charged Nanoparticles Produced by Splashing of Water’, Atmospheric Chemistry and Physics 9, no. 2 (16 January 2009): 357–67, https://0-doi-org.brum.beds.ac.uk/10.5194/acp-9-357-2009.

and references therein.

# Experiments

* Please include a more detailed description of the field mills and instrument used to measure polar conductivity; especially for polar conductivity; the instruments' operating principles and capabilities are critical to evaluate the scientific basis of the study, for example, if the polar conductivity is measured by a gerdien type instrument, what is the critical mobility?
* 2 different field mills are used but there is no description of how the different data sets are processed for use in this study
* lines 57 and 83: the field mill is called CS100 in line 57 and CS110 in line 83, please clarify.

# Results

* lines 97--101: Table A1 only shows 37 cases, 22 positive and 15 negative, have the ambiguous cases been omitted?
* line 98: Please describe in more detail how a "significant, short-term increase in negative electrical conductivity" is identified in each rain event.
* lines 104--106: Table A1 case 22 is an example of a frontal storm with no negative conductivity change. Case 23 is an example of air mass shower producing negative conductivity change. These examples contradict the statement. Please clarify.

# Discussion

* This discussion reads like it is a separate case study. Is it possible to connect the results to the discussion by relating the synoptic condition to the potential gradient signal and droplet diameter? For example, by stating that the frontal storm cases tend to have faster potential gradient changes and larger droplets compared to the air mass shower events (if it is true). It will be good to know that the 2 cases presented in the discussion are representative. Better if a metric for the potential gradient signal and droplet size distribution is reported for each case in table A1.
* The analysis presented hint strongly at mechanisms based on droplet size distribution and/or potential gradient fluctuations. The article will benefit from a little more discussion here.

# Appendix A

* Synoptic condition column: is the description the same for cases 16 and 17, and also 19 and 20? A little difficult to read there, can you put some spacing in to help?

Author Response

Dear reviewer! I send you responses to your questions and suggestions. Thank you for helping us improve our article!

Please see the attachment (Revised Manuscript with Changes Marked (13.10.2020).doc)

 

# Abstract

1) Comment of the reviewer: The abstract is vague and does not draw the reader in.

Response: The abstract was significantly changed (lines 12–25).

2) Comment of the reviewer: Please expand on the motivation / impact of research.

Response: The motivation / impact of research was included in the manuscript (lines 12–15).

3) Comment of the reviewer: Concluding statement can be more specific -> rain associated with frontal Cb produces a sharper change in atmospheric negative electrical conductivity than air mass showers.

Response: The concluding statement was changed (lines 21–23).

4) Comment of the reviewer: Why is the conclusion on droplet size (lines 166--168) not mentioned?

Response: The conclusion on droplet size was added (lines 23–25).

5) Comment of the reviewer: Briefly describe methodology / novelty.

Response: The methodology / novelty was described (lines 17–21).

# Intro

1) Comment of the reviewer: Air conductivity is dependent on air ions so work in atmospheric air ions must be considered here. See for e.g.

10. Hirsikko et al., ‘Atmospheric Ions and Nucleation: A Review of Observations’, Atmospheric Chemistry and Physics 11, no. 2 (26 January 2011): 767–98, https://0-doi-org.brum.beds.ac.uk/10.5194/acp-11-767-2011.

and references therein.

Response: The works on air ions was considered in the manuscript (lines 53–55).

2) Comment of the reviewer: Please mention previous work on rainfall and ion production, for e.g. A. K. Kamra, A. S. Gautam, and Devendraa Siingh, ‘Charged Nanoparticles Produced by Splashing of Raindrops’, Journal of Geophysical Research: Atmospheres 120, no. 13 (2015): 6669–81, https://0-doi-org.brum.beds.ac.uk/10.1002/2015JD023320.

10. Tammet, U. Hõrrak, and M. Kulmala, ‘Negatively Charged Nanoparticles Produced by Splashing of Water’, Atmospheric Chemistry and Physics 9, no. 2 (16 January 2009): 357–67, https://0-doi-org.brum.beds.ac.uk/10.5194/acp-9-357-2009.

and references therein.

Response: The works on rainfall and ion production was considered in the manuscript (lines 56–59).

# Experiments

1) Comment of the reviewer: Please include a more detailed description of the field mills and instrument used to measure polar conductivity; especially for polar conductivity; the instruments' operating principles and capabilities are critical to evaluate the scientific basis of the study, for example, if the polar conductivity is measured by a gerdien type instrument, what is the critical mobility?

Response: The detailed description of the instruments was included in the manuscript (lines 103–112 and 117–118).

2) Comment of the reviewer: 2 different field mills are used but there is no description of how the different data sets are processed for use in this study.

Response: The description of processing of electric field potential gradient data measured different field mill was added (lines 118–122).

3) Comment of the reviewer: lines 57 and 83: the field mill is called CS100 in line 57 and CS110 in line 83, please clarify.

Response: “CS100” was replaced to “CS110” (line 101).

# Results

1) Comment of the reviewer: lines 97--101: Table A1 only shows 37 cases, 22 positive and 15 negative, have the ambiguous cases been omitted?

Response: The ambiguous cases deliberately has been not included by us to the table.

2) Comment of the reviewer: line 98: Please describe in more detail how a "significant, short-term increase in negative electrical conductivity" is identified in each rain event.

Response: The "significant, short-term increase" is identified as the increase of negative air electrical conductivity of by more than 2 times relative to the previous undisturbed values. The description was added in the manuscript (lines 135–136).

3) Comment of the reviewer: lines 104--106: Table A1 case 22 is an example of a frontal storm with no negative conductivity change. Case 23 is an example of air mass shower producing negative conductivity change. These examples contradict the statement. Please clarify.

Response: Despite the fact that the λ– increase effect mainly was observed during the frontal Cb and mainly was not observed during the Cb intra-mass origin, there were also a few exceptions. The percentage of cases with the presence of the growth effect λ– and its absence for the frontal Cb and the Cb intra-mass origin was added in the manuscript (lines 140–142).

# Discussion

Comment of the reviewer: This discussion reads like it is a separate case study. Is it possible to connect the results to the discussion by relating the synoptic condition to the potential gradient signal and droplet diameter? For example, by stating that the frontal storm cases tend to have faster potential gradient changes and larger droplets compared to the air mass shower events (if it is true). It will be good to know that the 2 cases presented in the discussion are representative. Better if a metric for the potential gradient signal and droplet size distribution is reported for each case in table A1. The analysis presented hint strongly at mechanisms based on droplet size distribution and/or potential gradient fluctuations. The article will benefit from a little more discussion here.

Response: The cases (June 17, 2019 and June 23, 2019) discussed in detail in the article (see Figure 3 and Figure 4) are representative for the frontal Cb and Cb intra-mass origin cases respectively. Additional description of the results was added to the section (lines 202–209). The droplet sizes ranges for the precipitation cases with the growth effect λ– and its absence are near and are 0.5 ÷ 7 mm and 0.5 ÷ 4 mm respectively. In view of the above, we believe that rain particle size ranges should not be included in Table A1. However, we have added this information to the main text of article (lines 204–205). The metrics for the variations of electric field potential gradient and precipitation intensity was added for each case in Table A1. The more detailed discussion of mechanisms the Cb and rain effect on the variations  of electric field potential gradient and air electrical conductivity was done (lines 206–211).

# Appendix A

1) Comment of the reviewer: Synoptic condition column: is the description the same for cases 16 and 17, and also 19 and 20? A little difficult to read there, can you put some spacing in to help?

Response: Synoptic condition description for the cases of 16 and 17, and 19 and 20 is same respectively. The necessary corrections have been made to Table A1.

Author Response File: Author Response.doc

Reviewer 2 Report

The paper authored by Kalchikhin et al. deserves to be published on Atmosphere journal after addressing the following comments.

• It is too short, which does not show any results. It needs rephrasing and elaborating.
• Page 2 Line 87, The unit of electric conductivity is not correct, shall be “S/m”, applied to the whole paper.
• Figure 3’s caption, it shall mention the case is for cold frontal heavy rain
• Figure 4’s caption, shall add the intra-mass shower.
• Figure 4’s plots, shall add the plot of electroconductivity λ–, λ+, same as Figure 3.
• Page 7 Author Contributions, it is too long, simplify them.
• Page 7 Line 188, delete”)”.
• Table A1, in the “Synoptic conditions”, it has “Occluded front (PF)”. whereas in the text, it did not analyse this case. It would be interesting to add this case and know the results. If not, please give the reason.

Author Response

Dear reviewer! I send you responses to your questions and suggestions. Thank you for helping us improve our article!

Please see the attachment (Revised Manuscript with Changes Marked (13.10.2020).doc)

1) Comment of the reviewer: It is too short, which does not show any results. It needs rephrasing and elaborating.

Response: The manuscript was rephrased and elaborated (lines 12–25, 53–59, 103–112, 117–122, 135–136, 140–142 and 204–211).

2) Comment of the reviewer: Page 2 Line 87, The unit of electric conductivity is not correct, shall be “S/m”, applied to the whole paper.

Response:The unit of electric conductivity was corrected in the whole paper (lines 106 and 115, Figure 3, Figure 4).

3) Comment of the reviewer: Figure 3’s caption, it shall mention the case is for cold frontal heavy rain.

Response: The clarification that this rain case connected with the cold front passage was added to the caption of Figure 3 (lines 177–181).

4) Comment of the reviewer: Figure 4’s caption, shall add the intra-mass shower.

Response: The clarification that this rain case connected with the intra-mass shower was added to the caption of Figure 4 (lines 183–187).

5) Comment of the reviewer: Figure 4’s plots, shall add the plot of electroconductivity λ–, λ+, same as Figure 3.

Response: Plots with the λ+ electroconductivity and the λ– to λ+ ratio were added to Figure 4.

6) Comment of the reviewer: Page 7 Author Contributions, it is too long, simplify them.

Response: The authors contributions description was reduced (lines 224–229).

7) Comment of the reviewer: Page 7 Line 188, delete”)”.

Response: Symbol ”)” was deleted (line 231)

8) Comment of the reviewer: Table A1, in the “Synoptic conditions”, it has “Occluded front (PF)”. whereas in the text, it did not analyse this case. It would be interesting to add this case and know the results. If not, please give the reason.

Response: The rain cases connected with the occluded front passage were not described separately because they generally resemble the rain cases connected with the cold front passage.

Author Response File: Author Response.doc

Reviewer 3 Report

The manuscript studies the parameters of precipitation and fluctuations in the parameters of atmospheric electricity in the surface layer associated with the passage of cumulonimbus cloud in the southeast of Western Siberia in 2018-2019. There were 45 cases of heavy rainfall, including 8 cases of uncertain events. The simultaneous complex observations showed a significant difference in the variations in electrical conductivity during frontal heavy rain and intra-mass shower. Different distributions of droplets diameter were observed for frontal heavy rain and intra-mass showers. The study is well conducted and contains new results. The manuscript is recommended for publication in “Atmosphere” with minor revision.

• I recommend supplementing the annotation with quantitative results and details of the experiment.
• In the section 2, “Experiments”, I would recommend adding some geographic coordinates, such as the coordinates of the base station site (for an international reader).
• The label “11” is missing in the caption to Figure 1. And please unify the title of equipment “AMK-03” in line 61.
• Line 97: What defines the threshold for rain rate of 5 mm h^-1 (for example, why it is not 10 mm h^-1)? Was it resulted from comparison with meteorological observations for the area?
• Line 98: “there was a significant, short-term increase in negative electrical conductivity” – I would suggest adding a statistical description of the increase (its duration and magnitude or the slope) to quantify the difference for two major synoptic states, if possible.
• What were the synoptic conditions for the 8 cases of uncertain situations?
• Figure 3b: I think arrows 1-4 were not mentioned in the main text (lines 121-132).

Author Response

Dear reviewer! I send you responses to your questions and suggestions. Thank you for helping us improve our article!

Please see the attachment (Revised Manuscript with Changes Marked (13.10.2020).doc)

1) Comment of the reviewer: I recommend supplementing the annotation with quantitative results and details of the experiment.

Response: The quantitative results and experiment details were added to the annotation (lines 12–25).

2) Comment of the reviewer: In the section 2, “Experiments”, I would recommend adding some geographic coordinates, such as the coordinates of the base station site (for an international reader).

Response: The coordinates and altitude of the base station of GO IMCES as well as the link to its more detailed description was added to the Section 2 (lines 64–66).

3) Comment of the reviewer: The label “11” is missing in the caption to Figure 1. And please unify the title of equipment “AMK-03” in line 61.

Response: The unnecessary label “11” was deleted from Figure 1. The title of equipment “AMK-03” was unified (lines 77 and 79).

4) Comment of the reviewer: Line 97: What defines the threshold for rain rate of 5 mm h-1 (for example, why it is not 10 mm h-1)? Was it resulted from comparison with meteorological observations for the area?

Response:: The cases where the maximum rain intensity did not exceed 5 mm/h were omitted because this precipitation are light and usually do not have a significant impact to the variation of electrical quantities in the surface layer. This boundary value of rain intensity has been determined based on the analysis of our data and the work of other researchers [Bernard M. et al. Observations of the atmospheric electric field preceding intense rainfall events in the Dolomite Alps near Cortina d’Ampezzo, Italy. Meteorology and Atmospheric Physics 2019, 132, pp. 99–111].

5) Comment of the reviewer: Line 98: “there was a significant, short-term increase in negative electrical conductivity” – I would suggest adding a statistical description of the increase (its duration and magnitude or the slope) to quantify the difference for two major synoptic states, if possible.

Response: The "significant, short-term increase" is identified as the increase of negative air electrical conductivity of by more than 2 times relative to the previous undisturbed values. The description was added in the manuscript (lines 23–24 and 135–136).

6) Comment of the reviewer: What were the synoptic conditions for the 8 cases of uncertain situations?

Response: During the uncertain cases took place a difficult synoptic conditions which could not be unambiguously attributed to the frontal or intra-mass situations.

7) Comment of the reviewer: Figure 3b: I think arrows 1-4 were not mentioned in the main text (lines 121-132).

Response: The not used arrows 1-4 has been deleted from Figure 3.

Author Response File: Author Response.doc