Statistical Characteristics of Spread F in the Northeastern Edge of the Qinghai-Tibet Plateau during 2017–2022

Round 1

Reviewer 1 Report (Previous Reviewer 5)

Comments and Suggestions for Authors

This paper has improved significantly through the revisions. But it can still

benefit with the improvement in English.

 

Comments on the Quality of English Language

There is still room to improve the quality of English.

Below I provide examples of such sentences that necessitate

rephrasing:

a)  33 which is manifested as the diffused and spread echoes

b) 53 and winter and depends on the latitudes.

c) 170 spread F did not occur almost in the entire month. The highest value of

d) 189 It can be seen in Figure 6 that the spread F events

e) 204 Kp was chosen to represent geomagnetic activity on this day.

f) 205 there is no positive relationship between magnetic activity

g) 208-209 under geomagnetic activity condition. During pre-midnight period, there are no positive effects on SF.

h) 211-212 winter, there are no positive effects on SF for geomagnetic con ditions at nighttime.

i) 231 the occurrence probabilities of spread F

j) 270 Gravity waves were suggested to be an important factor

k) 311 with this value and then got the height histogram.

Author Response

Comments and Suggestions for Authors

This paper has improved significantly through the revisions. But it can still

benefit with the improvement in English.

 Rsp: Thank you for your valuable comments. English language has been further improved with the help of my colleagues who have a good ability of English writing. Please see the manuscript with changes marked.doc.

 

Comments on the Quality of English Language

There is still room to improve the quality of English.

Below I provide examples of such sentences that necessitate

rephrasing:

1. 33 which is manifested as the diffused and spread echoes

Rsp: Thank you for your valuable comments. The sentence has been modified. (please see lines 30-31, page 1)

1. b) 53 and winter and depends on the latitudes.

Rsp: Thank you for your valuable comments. The sentence has been rephrased. (please see lines 50-51, page 2)

1. c) 170 spread F did not occur almost in the entire month. The highest value of

Rsp: Thank you for your valuable comments. The sentence has been rephrased. (please see lines 166-169, page 8)

1. d) 189 It can be seen in Figure 6 that the spread F events

Rsp: Thank you for your valuable comments. The sentence has been modified. (please see lines 186-187, page 9)

1. e) 204 Kp was chosen to represent geomagnetic activity on this day.

Rsp: Thank you for your valuable comments. The sentence has been rephrased. (please see lines 201-202, page 10)

1. f) 205 there is no positive relationship between magnetic activity

Rsp: The sentence has been rephrased. (please see lines 202-203, page 10)

1. g) 208-209 under geomagnetic activity condition. During pre-midnight period, there are no positive effects on SF.

Rsp: Thank you for your valuable comments. The sentence has been rephrased. (please see lines 204-206, page 10)

1. h) 211-212 winter, there are no positive effects on SF for geomagnetic con ditions at nighttime.

Rsp: Thank you for your valuable comments. The sentence has been modified. (please see lines 208-209, page 10)

1. 231 the occurrence probabilities of spread F

Rsp: Thank you for your valuable comments. The sentence has been rephrased. (please see lines 226-228, page 11)

1. j) 270 Gravity waves were suggested to be an important factor

Rsp: Thank you for your valuable comments. The sentence has been rephrased. (please see lines 264-265, page 13)

1. k) 311 with this value and then got the height histogram.

Rsp: Thank you for your valuable comments. The sentence has been rephrased. (please see lines 308-311, page 14)

Reviewer 2 Report (Previous Reviewer 2)

Comments and Suggestions for Authors

The author has made necessary improvement on the paper. Now they finally did not purely attribute the spread F into gravity waves, but really discuss the geomagnetic activity induced spread F. The paper is now ok for publication

Comments on the Quality of English Language

mino english editing needed

Author Response

The author has made necessary improvement on the paper. Now they finally did not purely attribute the spread F into gravity waves, but really discuss the geomagnetic activity induced spread F. The paper is now ok for publication

Rsp: Thank you for your valuable comments. With the help of reviewers, we have improved the quality of the manuscript. Thanks again for reviewers’ valuable work on this manuscript.

 

Comments on the Quality of English Language

mino english editing needed

 Rsp: Thank you for your valuable comments. English language has been further improved with the help of my colleagues who have a good ability of English writing. Please see the manuscript with changes marked.doc.

Reviewer 3 Report (Previous Reviewer 3)

Comments and Suggestions for Authors

1) I suggest including dip latitudes of the stations used.
2) I believe you have underlines that must be removed on lines 84-104, lines 110-111, and lines 241-252.
3) I suggest increasing the font size in Figures 7 and 12.
4) Line 203: "(right panel)".
5) Lines 199-216: Recent studies show that during geomagnetic disturbed periods equatorial plasma bubbles can reach mid latitudes. That could me mentioned.

Author Response

Comments and Suggestions for Authors

• I suggest including dip latitudes of the stations used

Rsp: Thank you for your valuable comments. We have added the dip latitude of Zhangye. (please see line 14, page 1)

• I believe you have underlines that must be removed on lines 84-104, lines 110-111, and lines 241-252

Rsp: We have removed it when we submit it. The underline plotted in the pdf file might be associated with the submitted system error.

• I suggest increasing the font size in Figures 7 and 12

Rsp: Thank you for your valuable comments. The font size in Figures 7 and 12 has been increased.

• Line 203: "(right panel)"

Rsp: The word has been corrected. (please see line 200, page 10)

• Lines 199-216: Recent studies show that during geomagnetic disturbed periods equatorial plasma bubbles can reach mid latitudes. That could me mentioned.

Rsp: Thank you for your valuable comments. The sentence has been added and we have added some citations. (please see lines 195-196, page 10)

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

Comments and Suggestions for Authors

This paper studied the statistical characteristics of spread F recorded at Zhanye station during 2017-2022. To illustrate the diurnal and seasonal variation of Spread F, the number of occurrences of Spread F was counted from 2017 to 2022. The dependence of solar activity was also taken into account in the anlaysis, which indicates the occurrence of Spread F events has a negative relationship with solar activity. Finally, by means of citing the related research of other scholars in the discussion section, eliciting the gravity waves may explain the abnoraml higher occurrence rate of Spread F at Zhangye station.  

There are some problems, which must be solved before it is considered for publication.

1.It is recommended to extend the study period to one solar cycle.

2.It is recommended to add two or three stations for the study.

3.The figure 2(b) and figure 4 in your paper are a bit blurry. Please consider replacing them with clearer ones. 

4.The experimental part is not sufficient and it is suggested to introduce gravity wave data for analysis.

5.The significance of this paper is not expound sufficiently. The author need to highlight this paper's innovative contributions

Comments on the Quality of English Language

Extensive editing of English language required

Author Response

Open Review

(x) I would not like to sign my review report
( ) I would like to sign my review report

Quality of English Language

( ) I am not qualified to assess the quality of English in this paper
( ) English very difficult to understand/incomprehensible
( ) Extensive editing of English language required
(x) Moderate editing of English language required
( ) Minor editing of English language required
( ) English language fine. No issues detected

 

	Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	( )	( )	(x)	( )
Are all the cited references relevant to the research?	( )	(x)	( )	( )
Is the research design appropriate?	( )	( )	(x)	( )
Are the methods adequately described?	( )	( )	(x)	( )
Are the results clearly presented?	( )	( )	(x)	( )
Are the conclusions supported by the results?	( )	( )	(x)	( )

Comments and Suggestions for Authors

This paper studied the statistical characteristics of spread F recorded at Zhanye station during 2017-2022. To illustrate the diurnal and seasonal variation of Spread F, the number of occurrences of Spread F was counted from 2017 to 2022. The dependence of solar activity was also taken into account in the anlaysis, which indicates the occurrence of Spread F events has a negative relationship with solar activity. Finally, by means of citing the related research of other scholars in the discussion section, eliciting the gravity waves may explain the abnoraml higher occurrence rate of Spread F at Zhangye station.  

There are some problems, which must be solved before it is considered for publication.

1.It is recommended to extend the study period to one solar cycle.

Rsp: Thank you for your valuable comments. It is a good idea to study spread F over one solar cycle. Unfortunately, we only have the data in 6 years at Zhangye station.

2.It is recommended to add two or three stations for the study.

Rsp: Thank you for your valuable comments. For comparison, we have analyzed the data at Beijing in 2018 to study the effect of gravity waves on spread F at different stations.

3.The figure 2(b) and figure 4 in your paper are a bit blurry. Please consider replacing them with clearer ones.

Rsp: Thank you for your valuable comments. Figure 2(b) and figure 4 have been redrawed in the revised manuscript. However, figure 2b depends on the origin image format (png) from DPS4d.

4.The experimental part is not sufficient and it is suggested to introduce gravity wave data for analysis.

Rsp: Thank you for your valuable comments. We have added 4 pictures in Figure 11, which shows that SF almost occurred accompanied with TIDs. Some sentences were added in the revised manuscript. Please see lines 283-289, pages 13.

“The mid-latitude spread F is mainly caused by TIDs [4, 5], moreover, TIDs are the manifestation of gravity waves in the ionosphere [1, 35, 36]. To further study the relationship between spread F and TIDs/gravity waves, Figure 11 shows variations of the virtual heights at various frequencies on some typical days (January, 15, March 11, October 12, in 2017, and January 18 in 2019). The black lines in Figure 11 indicate the downward movement of the phase velocity of TIDs in the ionosphere, and gray parts represent the duration of SF. It could be seen that TIDs can occur frequently during the occurrence of SF.”

5.The significance of this paper is not expounded sufficiently. The author needs to highlight this paper's innovative contributions.

Rsp: Thank you for your valuable comments. Some sentences were added in the revised manuscript. Please see lines 11-16, pages 1.

“Previous research suggested that the source of travelling ionospheric disturbances (TIDs) over China is located in the southeastern and northeastern edge of the Qinghai–Tibet Plateau. Till now, there are no ground-based observations of the ionosphere in this region. Recently, an advanced digital ionosonde was installed at Zhangye station (39.2°N, 100.54°E) in the northeastern edge of the Qinghai–Tibet Plateau. It is an opportunity to verify the effect of gravity waves on the formation of midlatitude spread F by compared with observations in other regions of China sector.”

 

Comments on the Quality of English Language

Extensive editing of English language required

Rsp: Thank you for your valuable comments. English language has been improved with the help of my colleagues who have a good ability of English writing. Please see the manuscript with changes marked.doc

Submission Date

02 January 2024

Date of this review

21 Jan 2024 13:16:40

 

Reviewer 2 Report

Comments and Suggestions for Authors

This paper reports the spread F of a mid-latitude station near the Qinghai-Tibet plateau. The diurnal, seasonal and solar cycle variations are presented in detail. However, the discussion on the formation of spread F needs some improvement. I recommend the paper to have a major revision before suitable for publication

 

 

Main comments: for the exploration of the seasonal anomalies of spread F, the auhor attributes this to the solar activity and point out that GW pattern might vary with solar cycle. However, note that Vadas 2007 is only a simulation result. The author shall try to find papers providing observation evidence on GW pattern varying with solar cycle.

 

Also, the author directly arguing that spread F in mid-latitudes are caused by gravity waves. At least, they shall provide some description on the geomagnetic activity impacts on spread F. I suggests the author starts discussing the possible mechanism from the diagnostic terms of F region plasma, namely chemistry, transport due to EXB drift, neutral wind and ambipolar diffusion

 

Line 64 further investigation

 

 

Line 64-66 re-write the sentence as

 

While many studies have investigated the diurnal, seasonal, and solar cycle variations of midlatitude spread F, the formation mechanism of midlatitude spread F still requires further research due to the complex interplay of numerous factors

 

Line 89-98 the author just mention Fig 2, but did not give detailed description of the results in Fig 2

 

Fig 3 what is the grey part on the subplots??

 

Line 118 add ‘,’ after sunset

 

Line 119 event occurred almost everyday

 

Line 148 higher

 

Line 149 relatively lower

 

Line 159 that appeared in summer

 

Fig 8 what is the vertical dotted line on these subplots

 

Line 252 remove ‘influencing’

 

 

Line 253, 257, 258, 259 please be consistent on the density, so these three studies means neutral density, right??

 

Line 260-261 this ‘backstage manuplator’ is not suitable here, the author can just say play key roles

 

 

Line 271 gravity waves

 

Line 273-274 Therefore, the high occurrence probabilities of spread F at Zhangye may be attributed to the presence of strong gravity waves

 

Line 293 Therefore, more active gravity waves cause higher spread F occurrence in autumn and winter, which causes seasonal abnormalities of spread F

Comments on the Quality of English Language

moderate english revision needed

Author Response

Open Review

( ) I would not like to sign my review report
(x) I would like to sign my review report

Quality of English Language

( ) I am not qualified to assess the quality of English in this paper
( ) English very difficult to understand/incomprehensible
( ) Extensive editing of English language required
(x) Moderate editing of English language required
( ) Minor editing of English language required
( ) English language fine. No issues detected

 

	Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	( )	(x)	( )	( )
Are all the cited references relevant to the research?	( )	(x)	( )	( )
Is the research design appropriate?	( )	(x)	( )	( )
Are the methods adequately described?	( )	(x)	( )	( )
Are the results clearly presented?	( )	(x)	( )	( )
Are the conclusions supported by the results?	( )	(x)	( )	( )

Comments and Suggestions for Authors

This paper reports the spread F of a mid-latitude station near the Qinghai-Tibet plateau. The diurnal, seasonal and solar cycle variations are presented in detail. However, the discussion on the formation of spread F needs some improvement. I recommend the paper to have a major revision before suitable for publication 

Main comments: for the exploration of the seasonal anomalies of spread F, the author attributes this to the solar activity and point out that GW pattern might vary with solar cycle. However, note that Vadas 2007 is only a simulation result. The author shall try to find papers providing observation evidence on GW pattern varying with solar cycle. Rsp: We have added cite of Liu et al. (2017). (please see lines 322-323, page 14)

Liu, X., J. Yue, J. Xu, R. R. Garcia, J. M. Russell, III, M. Mlynczak, D. L. Wu, and T. Nakamura, Variations of global gravity waves derived from 14 years of SABER temperature observations, J. Geophys. Res. Atmos., 2017, 122, 6231–6249, doi:10.1002/2017JD026604.

 

Also, the author directly arguing that spread F in mid-latitudes are caused by gravity waves. At least, they shall provide some description on the geomagnetic activity impacts on spread F. I suggest the author starts discussing the possible mechanism from the diagnostic terms of F region plasma, namely chemistry, transport due to EXB drift, neutral wind and ambipolar diffusion.

Rsp: Thank you for your valuable comments. We have added some description on the geomagnetic activity impacts on spread F (please see lines 185-187, page 9). We totally agree with the comments, the geomagnetic activity can affect the occurrence of spread F depending on the local time. But the geomagnetic activity is not the point of this study, and in this study, statistical studies show that geomagnetic activity might have a little impact on spread F (please see Figure 8), Su et al. (2006) also suggest the occurrence of midlatitude irregularities apparently is not affected by the magnetic condition. therefore, we did not discuss geomagnetic activity in more detail in this study.

Su, S. Y., Liu, C. H., Ho, H. H. and Chao, C. K., Distribution characteristics of topside ionospheric density irregularities: Equatorial versus midlatitude regions, J. Geophys. Res., 2006, 111, A06305, doi:10.1029/2005JA011330.

 

Line 64 further investigation

Rsp: The word has been replaced. (please see line 62, page 2)

Line 64-66 re-write the sentence as

While many studies have investigated the diurnal, seasonal, and solar cycle variations of midlatitude spread F, the formation mechanism of midlatitude spread F still requires further research due to the complex interplay of numerous factors

Rsp: Thank you for your valuable comments. The sentence has been rewritten. (please see lines 60-62, page 2)

 

Line 89-98 the author just mention Fig 2, but did not give detailed description of the results in Fig 2

Rsp: Thank you for your valuable comments We have added some description of Fig 2. (please see lines 92-98, pages 3-4).

 

Fig 3 what is the grey part on the subplots??

Rsp: The grey parts indicate the data missed in Figure 3, and we have added description on Fig 3. (please see lines 99-101, page 4)

Line 118 add ‘,’ after sunset

Rsp: We have added. (please see line 121, page 5)

Line 119 event occurred almost everyday

Rsp: Thank you for your valuable comments. The sentence has been modified. (please see lines 121-122, page 5)

 

Line 148 higher

Rsp: The word has been modified. (please see line 150, page 7)

 

Line 149 relatively lower

Rsp: The word has been modified. (please see line 151, page 7)

Line 159 that appeared in summer

Rsp: The sentence has been modified. (please see lines 157-158, page 7)

Fig 8 what is the vertical dotted line on these subplots

Rsp: The solar 10.7 fluxes increase apparently after the vertical dotted line. We have added explanation. (please see line 178-179, page 9).

Line 252 remove ‘influencing’

Rsp: The word has been removed. (please see line 247, page 11)

Line 253, 257, 258, 259 please be consistent on the density, so these three studies means neutral density, right??

Rsp: Yes, it is, we also modified the sentences to avoid ambiguity. (please see lines 248, 252, 253,255, page 11)

Line 260-261 this ‘backstage manipulator’ is not suitable here, the author can just say play key roles

Rsp: Thank you for your valuable comments. We have replaced the phrase. (please see line 255, page 11)

Line 271 gravity waves

Rsp: The word has been modified. (please see line 265, page 12)

Line 273-274 Therefore, the high occurrence probabilities of spread F at Zhangye may be attributed to the presence of strong gravity waves

Rsp: Thank you for your valuable comments. We have replaced the sentence. (please see lines 267-268, page 12)

Line 293 Therefore, more active gravity waves cause higher spread F occurrence in autumn and winter, which causes seasonal abnormalities of spread

Rsp: Thank you for your valuable comments. We have replaced the sentence. (please see lines 309-310, page 14)

 

Comments on the Quality of English Language

moderate english revision needed

Rsp: Thank you for your valuable comments. English language has been improved with the help of my colleagues who have a good ability of English writing. Please see the manuscript with changes marked.doc

 

Submission Date

02 January 2024

Date of this review

14 Jan 2024 03:23:50

 

Reviewer 3 Report

Comments and Suggestions for Authors

This work discusses the occurrence of spread F in the ionosphere in midlatitude regions, focusing on the influence of atmospheric gravity waves. Using an advanced digital ionosonde installed at the Zhangye station, located on the northeastern edge of the Qinghai-Tibet Plateau. The investigation statistically analyzes diurnal, seasonal, and solar cycle variations in spread F occurrence probabilities. The results reported by the authors indicate significantly higher occurrence rates in Zhangye, attributed to gravity waves in the northeast Qinghai-Tibet Plateau, with seasonal implications and a negative relationship with solar activity.

I congratulate the authors on the work they have done so far, but according to my assessment, some clarifications, adjustments and improvements are needed. The manuscript is well-written, with good quality figures and graphical resources. My major concern with the work is its low contribution; it would be advisable for the authors to clarify the contribution of their research. Another deficiency in the paper that needs correction is the absence of a methodology section. This section should include explanations of how the data from the digisonde were treated, the procedures for pre-screening and outlier removal, and, in essence, all steps of data processing critical for this instrument should be presented. It is highly recommended, as explained below (item 3), to include two or more case studies to enhance the content of the work and elucidate the authors' arguments, thereby reinforcing their hypothesis and improving the paper's overall quality. Finally, I believe that the conclusion could also be improved. The following are my comments.

Major comments

1) How was the spread F identified? What were the criteria?This information is important and should be included in the text to inform readers.

2) Why the index selected for evaluation of the geomagnetic conditions (quiet/disturbed) was Ap? Also, depending on the time of the storms/substorms, their effects on ionosphere may take place several hours later. Did you consider these aspects?

3) As mentioned by the authors, previous studies already proposed that topographic characteristics of that region could lead to the existence of upward propagating waves, therefore, it is difficult to understand the novelty of the present work. Perhaps it would be more insightful to evaluate cases of gravity waves and spread F using the resources of the ionosondes (oscillations in the heights for distinct frequencies, etc.) instead of using hundreds of days piled up, what led to a dilution of possible signatures of gravity waves. It is difficult to remove the contribution of seasonal transition from possible gravity wave contributions when all the data is stacked.

Minor comments

1) Lines 22-23: “Ionograms also show”.

2) Line 33: “Booker and Wells”.

3) Line 35: “widely accepted”.

4) Lines 36-37: This sentence needs rephrasing.

5) Line 63: “might be due”.

6) Line 68: “in the northeastern” instead of “where right in the northeastern”.

7) Lines 89-98: Why is the text underscored?

8) Line 89: “SF” was not defined.

9) Line 119: “spread events occurred”.

10) Line 120-121: This sentence needs rephrasing.

11) Lines 223-234: Why is the text underscored?

12) Line 271: “gravity” in

 

 

Author Response

Open Review

(x) I would not like to sign my review report
( ) I would like to sign my review report

Quality of English Language

(x) I am not qualified to assess the quality of English in this paper
( ) English very difficult to understand/incomprehensible
( ) Extensive editing of English language required
( ) Moderate editing of English language required
( ) Minor editing of English language required
( ) English language fine. No issues detected

 

	Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	( )	(x)	( )	( )
Are all the cited references relevant to the research?	( )	( )	(x)	( )
Is the research design appropriate?	(x)	( )	( )	( )
Are the methods adequately described?	(x)	( )	( )	( )
Are the results clearly presented?	(x)	( )	( )	( )
Are the conclusions supported by the results?	( )	( )	(x)	( )

Comments and Suggestions for Authors

This work discusses the occurrence of spread F in the ionosphere in midlatitude regions, focusing on the influence of atmospheric gravity waves. Using an advanced digital ionosonde installed at the Zhangye station, located on the northeastern edge of the Qinghai-Tibet Plateau. The investigation statistically analyzes diurnal, seasonal, and solar cycle variations in spread F occurrence probabilities. The results reported by the authors indicate significantly higher occurrence rates in Zhangye, attributed to gravity waves in the northeast Qinghai-Tibet Plateau, with seasonal implications and a negative relationship with solar activity.

I congratulate the authors on the work they have done so far, but according to my assessment, some clarifications, adjustments and improvements are needed. The manuscript is well-written, with good quality figures and graphical resources. My major concern with the work is its low contribution; it would be advisable for the authors to clarify the contribution of their research. Another deficiency in the paper that needs correction is the absence of a methodology section. This section should include explanations of how the data from the digisonde were treated, the procedures for pre-screening and outlier removal, and, in essence, all steps of data processing critical for this instrument should be presented. It is highly recommended, as explained below (item 3), to include two or more case studies to enhance the content of the work and elucidate the authors' arguments, thereby reinforcing their hypothesis and improving the paper's overall quality. Finally, I believe that the conclusion could also be improved. The following are my comments.

Major comments

• How was the spread F identified? What were the criteria? This information is important and should be included in the text to inform readers.

Rsp: Thank you for your valuable comments. The criteria are based on Handbook of Ionogram Interpretation and Reduction (Piggott, W.R., Rawer, K., 1972.), and we have added in the revised manuscript. we also modified Figure 2 to show how to identify spread F.

Piggott, W.R., Rawer, K., 1972. U.R.S.I. Handbook of Ionogram Interpretation and Reduction. World Data Center A for Solar-Terrestrial Physics NOAA, Boulder, Colorado, pp. 17–18.

• Why the index selected for evaluation of the geomagnetic conditions (quiet/disturbed) was Ap? Also, depending on the time of the storms/substorms, their effects on ionosphere may take place several hours later. Did you consider these aspects?

Rsp: Thank you for your valuable comments. The Ap index can be converted from the Kp index, and the Ap index indicates the strength of the earth's magnetism in one day. Moreover，the effect of storm on SF depends on the local time. We have also preliminarily studied the effect of Ap index on SF, and we found that geomagnetic activity was the most active in 2017; however, the occurrence probability of midlatitude spread F was neither the highest nor the lowest. Su et al. also said that the occurrence of midlatitude irregularities apparently is not affected by the magnetic condition. Since our study is not a case study, but a statistical study, therefore, we did not discuss the specific effects of storm on it in detail here.

Su, S. Y., Liu, C. H., Ho, H. H. and Chao, C. K., Distribution characteristics of topside ionospheric density irregularities: Equatorial versus midlatitude regions, J. Geophys. Res., 2006, 111, A06305, doi:10.1029/2005JA011330.

3) As mentioned by the authors, previous studies already proposed that topographic characteristics of that region could lead to the existence of upward propagating waves, therefore, it is difficult to understand the novelty of the present work. Perhaps it would be more insightful to evaluate cases of gravity waves and spread F using the resources of the ionosondes (oscillations in the heights for distinct frequencies, etc.) instead of using hundreds of days piled up, what led to a dilution of possible signatures of gravity waves. It is difficult to remove the contribution of seasonal transition from possible gravity wave contributions when all the data is stacked.

Rsp: Thank you for your valuable comments. Previous research suggested that the source of travelling ionospheric disturbances (TIDs) over China is located in the southeastern and northeastern edge of the Qinghai–Tibet Plateau. Till now, there are no ground-based observations of the ionosphere in this region. Recently, an advanced digital ionosonde was installed at Zhangye station (39.2°N, 100.54°E) in the northeastern edge of the Qinghai–Tibet Plateau. It is an opportunity to verify the effect of gravity waves on the formation of midlatitude spread F by compared with observations in other regions of China sector.

These sentences mentioned above also have been added in the abstract of the revised manuscript. Moreover, we carried out the relationship between gravity waves/tids and spread F by iso-frequency plots (oscillations in the heights for distinct frequencies), please see lines 284-290, page 13. Mid-latitude spread F is mainly associated with mstids (Bowman, 1990). Iso-frequency plots also show that many TIDs can be observed frequently before the occurrence of spread F.

Bowman, G. G., A review of some recent work on mid-latitude spread-F occurrence as detected by ionosondes, J. Geomagn. Geoelectr., 1990, 42, 109-138, doi: 10.5636/jgg.42.10910.1541/ieejfms1990.111.5_494.

 

Minor comments

• Lines 22-23: “Ionograms also show”.

Rsp: The mistake has been modified and we also rephrase the sentence. (please see lines 23-24, page 1)

• Line 33: “Booker and Wells”.

Rsp: The mistake has been modified. (please see line 33, page 1)

• Line 35: “widely accepted”.

Rsp: Thank you for your valuable comments We have rephrased the sentence so the problem doesn't exist. (please see lines 34-35, page 1)

4) Lines 36-37: This sentence needs rephrasing.

Rsp: The sentence has been rephrased. (please see line 35-36, page 1)

• Line 63: “might be due”.

Rsp: Thank you for your valuable comments We have rephrased the sentence so the problem doesn't exist. (please see lines 58-59, page 1)

6) Line 68: “in the northeastern” instead of “where right in the northeastern”.

Rsp: The sentence has been modified. (please see lines 63-64, page 2)

7) Lines 89-98: Why is the text underscored?

Rsp: Sorry, we have removed the underline now. (please see lines 85-101, pages 3-4)

8) Line 89: “SF” was not defined.

Rsp: We have added the defined. (please see line 9, page 1)

9) Line 119: “spread events occurred”.

Rsp: The sentence has been modified. (please see lines 121-122, page 5)

10) Line 120-121: This sentence needs rephrasing.

Rsp: The sentence has been rephrased. (please see lines 122-123, page 5)

11) Lines 223-234: Why is the text underscored?

Rsp: We have removed the underline. (please see lines 220-230, pages 10-11)

12) Line 271: “gravity” in

Rsp: The word has been modified. (please see line 264, page 12)

 

Submission Date

02 January 2024

Date of this review

12 Jan 2024 17:50:17

 

Reviewer 4 Report

Comments and Suggestions for Authors

Review of "Statistical Characteristics of Spread F in the Northeastern Edge 2 of the Qinghai–Tibet Plateau during 2017-2022" by Liu et al.

 

Summary: This paper investigates the occurrence of spread F in the ionosphere, focusing on the Zhangye station on the northeastern edge of the Qinghai–Tibet Plateau. The study employs statistical analysis of spread F events recorded from 2017 to 2022. The results reveal similar diurnal, seasonal, and solar cycle variations as in previous studies, with the highest occurrence probabilities observed post-midnight, in summer and winter, and a negative correlation with solar activity. Notably, the occurrence rates of spread F at Zhangye station are unusually high compared to other midlatitude stations. The study suggests that gravity waves in the northeast of the Qinghai–Tibet Plateau may contribute to this abnormality. The paper is effectively written and includes comprehensive figures. However, I suggest a more thorough exploration of the gravity wave mechanism. It seems the authors attribute Spread F events in autumn and winter to gravity waves, primarily inspired by Wan's article, but there's a need for a more detailed explanation of the mechanism and supporting evidence for the process. Adding this discussion could enhance the paper's depth and provide a clearer understanding.

 

Specific Comments and Suggestions:

Line 30-33: Please add citation(s) about the scales of spread F structure range that you find appropriate. I just searched and found this one, Abdu, M. A., Muralikrishna, P., Batista, I. S., & Sobral, J. H. A. (1991). Rocket observation of equatorial plasma bubbles over Natal, Brazil, using a high‐frequency capacitance probe. Journal of Geophysical Research: Space Physics, 96(A5), 7689-7695.

 

Line 41-42: “... TIDs 41 are influenced by gravity waves.” Please add citation(s) for this statement. This article shows a good example in which TIDs can be directly caused by gravity waves: Xu, S., Yue, J., Xue, X., Vadas, S. L., Miller, S. D., Azeem, I., ... & Zhang, S. (2019). Dynamical coupling between hurricane matthew and the middle to upper atmosphere via gravity waves. Journal of Geophysical Research: Space Physics, 124(5), 3589-3608.

 

Line 44-45: Similar to the suggestions above, more citations should be added to support the statement here.

 

Line 93: “The antennas of two ionosondes are also different.” How would that influence the observation results?

 

Line 89-98: How is a Spread F event distinguished from ionograms? For example, if 2 consecutive ionograms both observe SF events, are they defined as 2 events or 1 event? Please describe and add that information in the text and maybe circle the Spread F signature in Figure 2. I also suggest the authors include typical normal (non-SF) ionograms in Figure 2 as well.

 

Line 119: The word “daily” has ambiguity because SFs are observed during almost the night only. I suggest using “almost every day”.

 

Line 134-137: Can you make sure the way to define the SF events in article [6] about the Changchun and Urumqi cases was consistent with the current article?

 

Line 289-292: It would be great if the author could explain why gravity wave activities are related to abrupt virtual height increases in Figure 11.

Comments on the Quality of English Language

Line 166-167: however -> but

Line 208: closed -> close

Line 212: In the terms of -> In terms of 

Line 231: It is also can be seen -> It also can be seen

 

Line 276-278: This sentence is very hard to read. This might be better:

During the autumn and winter periods from 2017 to 2020, the occurrence probabilities of spread F events at Zhangye are comparable to, if not higher than, occurrences in the summer months. Notably, the probabilities observed in 2019 and 2021 during these colder seasons surpass those recorded in the respective summer periods.

 

Line 287: closed -> close

Author Response

Open Review

(x) I would not like to sign my review report
( ) I would like to sign my review report

Quality of English Language

( ) I am not qualified to assess the quality of English in this paper
( ) English very difficult to understand/incomprehensible
( ) Extensive editing of English language required
( ) Moderate editing of English language required
(x) Minor editing of English language required
( ) English language fine. No issues detected

 

	Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	( )	(x)	( )	( )
Are all the cited references relevant to the research?	(x)	( )	( )	( )
Is the research design appropriate?	(x)	( )	( )	( )
Are the methods adequately described?	( )	(x)	( )	( )
Are the results clearly presented?	(x)	( )	( )	( )
Are the conclusions supported by the results?	( )	(x)	( )	( )

Comments and Suggestions for Authors

Review of "Statistical Characteristics of Spread F in the Northeastern Edge 2 of the Qinghai–Tibet Plateau during 2017-2022" by Liu et al.

 

Summary: This paper investigates the occurrence of spread F in the ionosphere, focusing on the Zhangye station on the northeastern edge of the Qinghai–Tibet Plateau. The study employs statistical analysis of spread F events recorded from 2017 to 2022. The results reveal similar diurnal, seasonal, and solar cycle variations as in previous studies, with the highest occurrence probabilities observed post-midnight, in summer and winter, and a negative correlation with solar activity. Notably, the occurrence rates of spread F at Zhangye station are unusually high compared to other midlatitude stations. The study suggests that gravity waves in the northeast of the Qinghai–Tibet Plateau may contribute to this abnormality. The paper is effectively written and includes comprehensive figures. However, I suggest a more thorough exploration of the gravity wave mechanism. It seems the authors attribute Spread F events in autumn and winter to gravity waves, primarily inspired by Wan's article, but there's a need for a more detailed explanation of the mechanism and supporting evidence for the process. Adding this discussion could enhance the paper's depth and provide a clearer understanding.

 

Specific Comments and Suggestions:

Line 30-33: Please add citation(s) about the scales of spread F structure range that you find appropriate. I just searched and found this one, Abdu, M. A., Muralikrishna, P., Batista, I. S., & Sobral, J. H. A. (1991). Rocket observation of equatorial plasma bubbles over Natal, Brazil, using a high‐frequency capacitance probe. Journal of Geophysical Research: Space Physics, 96(A5), 7689-7695.

Rsp: The citation has been added. (please see lines 30-31, page 1)

 

Line 41-42: “... TIDs 41 are influenced by gravity waves.” Please add citation(s) for this statement. This article shows a good example in which TIDs can be directly caused by gravity waves: Xu, S., Yue, J., Xue, X., Vadas, S. L., Miller, S. D., Azeem, I., ... & Zhang, S. (2019). Dynamical coupling between hurricane matthew and the middle to upper atmosphere via gravity waves. Journal of Geophysical Research: Space Physics, 124(5), 3589-3608.

Rsp: The citation has been added. (please see line 36-38, pages 1-2)

 

Line 44-45: Similar to the suggestions above, more citations should be added to support the statement here.

Rsp: Some citations have been added. (please see lines 40-41, page 2)

 

Line 93: “The antennas of two ionosondes are also different.” How would that influence the observation results?

Rsp: Thank you for your valuable comments. The following sentences were added in the revised manuscript. please see lines 90-101, pages 3-4.

“The elevation of antennas can affect returned echoes from different positions in the ionosphere over the transmitter and then lead to some slightly different echoes on ionograms. Therefore, to test the difference of observations from these two ionosondes, Figure 2 shows two data sets of ionograms recorded by WISS and DPS-4D at the same time at Wuhan, respectively. The criterion of SF is based on Handbook of Ionogram Interpretation and Reduction [43], and the red rectangles mark the trace of the F2 layer. For the operator, Figures 2a and 2b corresponds spread F, however, there are no spread F in Figures 2c and 2d. Figure 2 show that there are no differences on identification of spread F from ionograms recorded by WISS and DPS-4D. To further study the differences between these two systems, Figure 3 shows the comparison of SF observations on some days in September and December in 2020. The black bars indicate the occurrences of spread F events and grey parts indicate the data missed in Figure 3. It can be seen that the two digital ionosondes have similar results for SF observation.”

 

 

 

Line 89-98: How is a Spread F event distinguished from ionograms? For example, if 2 consecutive ionograms both observe SF events, are they defined as 2 events or 1 event? Please describe and add that information in the text and maybe circle the Spread F signature in Figure 2. I also suggest the authors include typical normal (non-SF) ionograms in Figure 2 as well.

 

Rsp: Thank you for your valuable comments.

The criterion of SF is based on Handbook of Ionogram Interpretation and Reduction (Piggott, W.R., Rawer, K., 1972.), and we have added related statement in the revised manuscript. Please see lines 94-98, pages 4.

In this study, we did not calculate the occurrence rate of spread F on one day. This study focused on the occurrence rate of local times on different days (P(Y, M, LT)=(n(Y, M, LT))/(N(Y, M, LT))×100% ). Therefore, for instance, if the event occurred at 20:00 LT, we think it is one event when calculating the occurrence rate at 20:00 LT for all days. When there is no one at 21:00 LT, then we think that there is no occurrence on this day at 21:00 LT. However, if the event lasted from 20:00 LT to 21:00 LT. the event is considered as one case at 20:00 LT on this day. It is also considered as one case at 21:00 LT on this day. As a result, this study can avoid this question about how is a Spread F event distinguished from ionograms, which is just used to calculate the occurrence rate of spread F on one day.

 

Piggott, W.R., Rawer, K., 1972. U.R.S.I. Handbook of Ionogram Interpretation and Reduction. World Data Center A for Solar-Terrestrial Physics NOAA, Boulder, Colorado, pp. 17–18.

 

 

Line 119: The word “daily” has ambiguity because SFs are observed during almost the night only. I suggest using “almost every day”.

Rsp: The sentence has been modified. (please see line 121-122, page 5)

 

Line 134-137: Can you make sure the way to define the SF events in article [6] about the Changchun and Urumqi cases was consistent with the current article?

 

Rsp: Thank you for your valuable comments. The identification of spread F is based on the Handbook of Ionogram Interpretation and Reduction (Piggott, W.R., Rawer, K., 1972). Certainly, there are some differences on the identification of spread F depends on operators. For statitiscal studies, we think that it might be ignored.

 

Piggott, W.R., Rawer, K., 1972. U.R.S.I. Handbook of Ionogram Interpretation and Reduction. World Data Center A for Solar-Terrestrial Physics NOAA, Boulder, Colorado, pp. 17–18.

 

Line 289-292: It would be great if the author could explain why gravity wave activities are related to abrupt virtual height increases in Figure 11.

Rsp: Thank you for your valuable comments. Abrupt virtual height increases are associated with wave-like structure in the ionosphere. It is well known that wave-like structure in the ionosphere are associated with gravity waves (Bowman,1990). These sentences were added in the revised manuscript. Please see lines 301-303, pages 14.

 

Bowman, G. G., A review of some recent work on mid-latitude spread-F occurrence as detected by ionosondes, J. Geomagn. Geoelectr., 1990, 42, 109-138, doi: 10.5636/jgg.42.10910.1541/ieejfms1990.111.5_494.

 

Comments on the Quality of English Language

Line 166-167: however -> but

Rsp: The word has been replaced. (please see lines 164-165, page 8)

Line 208: closed -> close

Rsp: The word has been replaced. (please see lines 205-206, page 10)

Line 212: In the terms of -> In terms of

Rsp: The sentence has been modified. (please see lines 209-211, page 10)

Line 231: It is also can be seen -> It also can be seen

Rsp: The sentence has been modified. (please see lines 228-230, page 11.)

Line 276-278: This sentence is very hard to read. This might be better:

During the autumn and winter periods from 2017 to 2020, the occurrence probabilities of spread F events at Zhangye are comparable to, if not higher than, occurrences in the summer months. Notably, the probabilities observed in 2019 and 2021 during these colder seasons surpass those recorded in the respective summer periods.

Rsp: Thank you for your valuable comments The sentence has been replaced. (please see lines 277-280, page 13.)

Line 287: closed -> close

Rsp: The word has been replaced. (please see lines 300-301, page 14)

 

Submission Date

02 January 2024

Date of this review

22 Jan 2024 10:11:50

 

Reviewer 5 Report

Comments and Suggestions for Authors

This paper seems to be the result of adopting methodologies and approaches in similar recent papers. The level of clarity though is very low because the scientific writing is extremely bad and totally inadequate to support the main findings of this paper. The paper has to go through an extensive revision in terms of English and scientific writing and then undergo a second revision to be evaluated. I have noted a lot of issues regarding scientific writing but it will take a lot of hours to be listed here as every few lines an additional expression mistake comes up. Therefore I leave it to the authors to seek help and improve considerably the manuscript in this respect before revisiting it for a review. Below I include some points that need to be addressed in this major revision:

1)      Line282-292:There is no explanation how Figure 11 was generated and most importantly how does it contribute to the conclusions that the authors want to support.

2)      Line285-286:Why are summer months (due to Es) excluded when we  are mostly interested in afternoon and nighttime and post-midnight (as authors claim) effects where spread F is mostly expected to appear?.

3)      There are additional papers that the authors need to consider in their literature review and discussion such as the following. The justification for:

I)                    deals with mid-latitude data from multiple stations and covers an extended range of dependencies as the authors are attempting in their paper

and for

II)                  that discusses extensively the aspect of TIDs as the authors are trying to highlight I their paper

Papers I) and II) are given below.

I)                    Multi-station investigation of spread F over Europe during low to high solar activity J. Sp Weather Climate., 8, A27. https://doi.org/10.1051/swsc/2018006

II)                  Mid-latitude spread F over an Extended European area Journal of Atmos and Solar-Terrestrial Physics https://doi.org/10.1016/j.jastp.2021.105706

 

Comments on the Quality of English Language

Extensive improvement needed to enable better reviewing of the scientific aspect of the paper.

Author Response

Open Review

(x) I would not like to sign my review report
( ) I would like to sign my review report

Quality of English Language

( ) I am not qualified to assess the quality of English in this paper
(x) English very difficult to understand/incomprehensible
( ) Extensive editing of English language required
( ) Moderate editing of English language required
( ) Minor editing of English language required
( ) English language fine. No issues detected

 

	Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	( )	( )	(x)	( )
Are all the cited references relevant to the research?	( )	(x)	( )	( )
Is the research design appropriate?	( )	(x)	( )	( )
Are the methods adequately described?	( )	(x)	( )	( )
Are the results clearly presented?	( )	( )	(x)	( )
Are the conclusions supported by the results?	( )	( )	(x)	( )

Comments and Suggestions for Authors

This paper seems to be the result of adopting methodologies and approaches in similar recent papers. The level of clarity though is very low because the scientific writing is extremely bad and totally inadequate to support the main findings of this paper. The paper has to go through an extensive revision in terms of English and scientific writing and then undergo a second revision to be evaluated. I have noted a lot of issues regarding scientific writing but it will take a lot of hours to be listed here as every few lines an additional expression mistake comes up. Therefore I leave it to the authors to seek help and improve considerably the manuscript in this respect before revisiting it for a review. Below I include some points that need to be addressed in this major revision:

• Line282-292: There is no explanation how Figure 11 was generated and most importantly how does it contribute to the conclusions that the authors want to support.

Rsp: Thank you for your valuable comments. Some sentences were added in the revised manuscript to explain how Figure 12 was generated. Please see lines 292-296, page 13.

“For virtual height histograms of ionograms, all pixels including noise are summed at each height for all frequencies on ionograms, then each pixel is weighted with this value and then got the height histogram. A virtual height-time display is obtained by converting the height histogram into a single vertical line and plotting this line obtained from each successive ionogram as a function of time [40].”

Abrupt virtual height increases are associated with wave-like structure in the ionosphere. It is well known that wave-like structure in the ionosphere are associated with gravity wave. These sentences were added in the revised manuscript. Please see lines 301-303, page14.

 

• Line285-286: Why are summer months (due to Es) excluded when we are mostly interested in afternoon and nighttime and post-midnight (as authors claim) effects where spread F is mostly expected to appear?

Rsp: Thank you for your valuable comments. Some sentences were added in the revised manuscript to explain it. Please see lines 296-300, pages 13-14.

“January, December, March and October were selected to represent winter, spring and autumn The occurrence rates of spread F are mostly similar in summer compared with observations in other regions. This study focused on the abnormal phenomena of the occurrence rate in spring, autumn, winter. Therefore, the summer months were not shown in Figure 12.”

3) There are additional papers that the authors need to consider in their literature review and discussion such as the following. The justification for:

1. I) deals with mid-latitude data from multiple stations and covers an extended range of dependencies as the authors are attempting in their pape and fo II that discusses extensively the aspect of TIDs as the authors are trying to highlight I their paper

Papers I) and II) are given below.

I) Multi-station investigation of spread F over Europe during low to high solar activity Sp Weather Climate., 8, A27. https://doi.org/10.1051/swsc/2018006

II) Mid-latitude spread F over an Extended European area Journal of Atmos and Solar-Terrestrial Physics https://doi.org/10.1016/j.jastp.2021.105706

Rsp: Thank you for your valuable comments. These citations were added in the revised manuscript. (please see lines 51-52, page 2 and lines 36-38, pages 1-2)

 

Comments on the Quality of English Language

Extensive improvement needed to enable better reviewing of the scientific aspect of the paper.

Rsp: Thank you for your valuable comments. English language has been improved with the help of my colleagues who have a good ability of English writing. Please see the manuscript with changes marked.doc

 

Submission Date

02 January 2024

Date of this review

29 Jan 2024 21:33:23

 

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

 

The author has almost answered all my questions and comments. However, there is one question that the author did not give satisfied answer and make corresponding improvements.

Also, the author directly arguing that spread F in mid-latitudes are caused by gravity waves. At least, they shall provide some description on the geomagnetic activity impacts on spread F. I suggest the author starts discussing the possible mechanism from the diagnostic terms of F region plasma, namely chemistry, transport due to EXB drift, neutral wind and ambipolar diffusion.

Rsp: Thank you for your valuable comments. We have added some description on the geomagnetic activity impacts on spread F (please see lines 185-187, page 9). We totally agree with the comments, the geomagnetic activity can affect the occurrence of spread F depending on the local time. But the geomagnetic activity is not the point of this study, and in this study, statistical studies show that geomagnetic activity might have a little impact on spread F (please see Figure 8), Su et al. (2006) also suggest the occurrence of midlatitude irregularities apparently is not affected by the magnetic condition. therefore, we did not discuss geomagnetic activity in more detail in this study.

Su, S. Y., Liu, C. H., Ho, H. H. and Chao, C. K., Distribution characteristics of topside ionospheric density irregularities: Equatorial versus midlatitude regions, J. Geophys. Res., 2006, 111, A06305, doi:10.1029/2005JA011330.

 

I think the description is too sparse, just two lines are far less enough. I think the author need a long paragraph to discuss the geomagnetic activity modulation on spread F. As the author shall make sure what they are describing is really generated by gravity waves, not from geomagnetic activity!

Comments on the Quality of English Language

minor english revision needed

Author Response

please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript has improved substantially. I would point out that the conclusion is substandard and needs to be improved. I also think that the authors should include a case study for one evening, which would set the paper apart from others in the literature. English requires revision.

Minor points:

Line 36: “equatorial spread F” Line 111: “ Figure 2 shows” Lines 136-137: Sentence must be corrected Lines 222-224: Sentence must be corrected

Comments on the Quality of English Language

The new sentences need to be grammatically revised

Reviewer 4 Report

Comments and Suggestions for Authors

The authors have generally addressed all comments raised by reviewers. I suggest accepting this paper.

Reviewer 5 Report

Comments and Suggestions for Authors

The issues I raised in my original revision have been addressed.

 

Comments on the Quality of English Language

I still believe that the scientific writing can be improved.

Below I provide some phrases that underline this point:

The criterion of SF is based

For the operator, Figures 2a and 2b corresponds spread F

Figure 4 shows that the occurrence was shown in Figure 4.of spread F as a function of local time and day of year

A recent study [7] which12] has got the similar results in the occurrence

Equatorial spread F was found has inverse association with magnetic activity [22-24], however, Su et al. suggested that the occurrence of midlatitude irregularities apparently is not affected by the magnetic condition [25].