Fair-Weather Near-Surface Atmospheric Electric Field Measurements at the Zhongshan Chinese Station in Antarctica

Round 1

Reviewer 1 Report (New Reviewer)

Very interesting article. I am recommending accept with minor corrections. But there are some minor issues that require your attention.

 

- Abstract needs to contain (to include) five main elements: 

1.     Introduction. This is the first part of the abstract, and should be brief and attractive to the reader at the same time. ... (one to two sentences) 

2.     Research significance. This usually answers the question: Why did you do this research? (one to two sentences) 

3.     Methodology. ... (one to two sentences)

4.     Results. ... (one to two sentences)

5.     Brief summary of the conclusions. (one to two sentences)

A good informative abstract acts as a surrogate for the work itself. An abstract is a 150- to 250-word paragraph that provides readers with a quick overview of your work and how the article is organised. It should express your central idea and your key points; it should also suggest any implications or applications of the research you discuss in the paper.

 

- Do you think combining the discussion with conclusion is a good structure for this paper? Because I think your chapters are already separated, and the sentence that starts with 'In summary, to study the baseline variability characteristics' is already separating the discussion and conclusion chapters of the paper. Why not just separate the two, and check if the chapters address the requirements of each chapter. The conclusion is the best chapter to outline your key findings and key conclusions. You should make use of the conclusion chapter to make your article more readable, and since most readers would focus a great deal of their attention on the conclusion, this section should make the key conclusions more visible (and hence more interesting).  

 

- Did you consider the potential values of using new technologies and algorithms for the future improvements of the Electric Field Measurements at the Zhongshan Chinese Station

because fro example, low memory devices that also require low energy, could run for a very long period of time, without human intervention. There is a new article on this topic, titled ‘Algorithms for Artificial Intelligence on Low Memory Devices’ - see: https://ieeexplore.ieee.org/document/9502714  Because one section that seems to be missing from your paper is the 'future directions' and the 'limitations of the study'. It would be interesting to see a few sentences review and comparison of your work in the discussion chapter, in relations to this recent study in a related topics.

 

Otherwise, I think this is a really interesting study and I think it deserves publication. Well done. 

 

 

I am looking forward to reading the updated version of this article. 

Author Response

Dear Editors and Reviewers:

Thank you for your kind letter of our manuscript (applsci-1907198), "Fair-Weather Near-Surface Atmospheric Electric Field Measurements at the Zhongshan Chinese Station in Antarctica" on August 24, 2022. We have studied the reviewers’ comments carefully and made revisions, which are shown in green. Please find attached the revised version, which we would like to submit for your kind consideration.

We thank the time and efforts of the both referees to evaluate and improve the manuscript, and would like to respond the referees as follows. Our response are enclosed in brackets [ ] and are marked by red, just placed following the original comments.

 

Reviewer #1: Very interesting article. I am recommending accept with minor corrections. But there are some minor issues that require your attention.

- Abstract needs to contain (to include) five main elements: 

1. Introduction. This is the first part of the abstract, and should be brief and attractive to the reader at the same time. ... (one to two sentences) 
2. Research significance. This usually answers the question: Why did you do this research? (one to two sentences) 
3. Methodology. ... (one to two sentences)
4. Results. ... (one to two sentences)
5. Brief summary of the conclusions. (one to two sentences)

A good informative abstract acts as a surrogate for the work itself. An abstract is a 150- to 250-word paragraph that provides readers with a quick overview of your work and how the article is organised. It should express your central idea and your key points; it should also suggest any implications or applications of the research you discuss in the paper.

Response: [Thank you for your detailed comments and very useful suggestions regarding the abstract. We have already studied your proposals and improved the abstract on lines 18-23 in the revised version.]

- Do you think combining the discussion with conclusion is a good structure for this paper? Because I think your chapters are already separated, and the sentence that starts with 'In summary, to study the baseline variability characteristics' is already separating the discussion and conclusion chapters of the paper. Why not just separate the two, and check if the chapters address the requirements of each chapter. The conclusion is the best chapter to outline your key findings and key conclusions. You should make use of the conclusion chapter to make your article more readable, and since most readers would focus a great deal of their attention on the conclusion, this section should make the key conclusions more visible (and hence more interesting).  

Response: [Thank you for your very important and useful comments. As you suggested, we apologize for ignoring this detail before, the conclusion section should be separated out and it should be more highlighted and focused. We have made the discussion and conclusion separated in the revised version.]

- Did you consider the potential values of using new technologies and algorithms for the future improvements of the Electric Field Measurements at the Zhongshan Chinese Station

because fro example, low memory devices that also require low energy, could run for a very long period of time, without human intervention. There is a new article on this topic, titled ‘Algorithms for Artificial Intelligence on Low Memory Devices’ - see: https://ieeexplore.ieee.org/document/9502714  Because one section that seems to be missing from your paper is the 'future directions' and the 'limitations of the study'. It would be interesting to see a few sentences review and comparison of your work in the discussion chapter, in relations to this recent study in a related topics.

Response: [Thank you. These relevant descriptions have been added on lines 371-376 in the revised version. We will consider new measurement techniques and AI algorithms in the near future, and we have already made many attempts to do so now, thanks again.]

Otherwise, I think this is a really interesting study and I think it deserves publication. Well done. 

I am looking forward to reading the updated version of this article. 

Response: [Thank you for your positive comments.]

 

We tried our best to improve the manuscript and made some changes in the manuscript. We earnestly appreciate the Editors/Reviewers’ work and hope that the corrections will be met with approval. Once again, thank you very much for your comments and suggestions.

Author Response File: Author Response.doc

Reviewer 2 Report (New Reviewer)

New interesting measurements of the fair weather electric field are presented in the paper.

The authors have shown the difference of this field in clear Antarctica and above dirty populated grounds.

It would be interesting to add in future simultaneous measurements of air conductivity for better understanding of the results.

Also models of the ionospheric electric field must be used to separate the income of the variations of the ionospheric potential above the observatory. Now the authors only mention this income.

Nevertheless the paper is interesting and can be published as it is.

 

Couple minor corrections:

 

Line 41: 60 km is too much. Less than 5% of the potential difference ionosphere-ground is above 20 km and much less above 30 km as shown in Fig. 5 in [V.V. Denisenko, M.J. Rycroft, R.G. Harrison. Mathematical Simulation of the Ionospheric Electric Field as a Part of the Global Electric Circuit. Surveys in Geophysics, 2019. 40(1), 1-35. DOI: 10.1007/s10712-018-9499-6]

 

Line 290 and further: numbers like 111.5% are senseless precise, 110% looks more correct.

Author Response

Dear Editors and Reviewers:

Thank you for your kind letter of our manuscript (applsci-1907198), "Fair-Weather Near-Surface Atmospheric Electric Field Measurements at the Zhongshan Chinese Station in Antarctica" on August 24, 2022. We have studied the reviewers’ comments carefully and made revisions, which are shown in green. Please find attached the revised version, which we would like to submit for your kind consideration.

We thank the time and efforts of the both referees to evaluate and improve the manuscript, and would like to respond the referees as follows. Our response are enclosed in brackets [ ] and are marked by red, just placed following the original comments.

 

Reviewer #2: New interesting measurements of the fair weather electric field are presented in the paper.

The authors have shown the difference of this field in clear Antarctica and above dirty populated grounds.

It would be interesting to add in future simultaneous measurements of air conductivity for better understanding of the results.

Also models of the ionospheric electric field must be used to separate the income of the variations of the ionospheric potential above the observatory. Now the authors only mention this income.

Nevertheless the paper is interesting and can be published as it is.

Response: [Thank you for your detailed and positive comments. Your suggestions were very helpful. As you suggest, we are considering the use of an integrated detection device which can detect several physical parameters in real time, including positive and negative ion concentration, atmospheric conductivity, special gases and meteorological conditions. Sorry, we apologize for the missing the separation the income of the variations of the ionospheric potential above the observatory before and we will study the model in more details later on.]

 

Couple minor corrections:

Line 41: 60 km is too much. Less than 5% of the potential difference ionosphere-ground is above 20 km and much less above 30 km as shown in Fig. 5 in [V.V. Denisenko, M.J. Rycroft, R.G. Harrison. Mathematical Simulation of the Ionospheric Electric Field as a Part of the Global Electric Circuit. Surveys in Geophysics, 2019. 40(1), 1-35. DOI: 10.1007/s10712-018-9499-6]

Response: [Thank you. The Fig. 5 in that paper has been studied and “60 km” has been removed in the revised version.]

Line 290 and further: numbers like 111.5% are senseless precise, 110% looks more correct.

Response: [Thank you and all the numbers like 111.5% have been changed.]

 

We tried our best to improve the manuscript and made some changes in the manuscript. We earnestly appreciate the Editors/Reviewers’ work and hope that the corrections will be met with approval. Once again, thank you very much for your comments and suggestions.

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

The paper presents measurements of the fair-weather electric potential gradient (PG) at locations in the Antarctic and in Beijing, and shows a diurnal curve with a shape similar to the classic Carnegie one. However, the magnitude of the PG found at the Zhongshan Station exceeds values found elsewhere by nearly a factor of three. Furthermore, even the measurement taken in Beijing with a similar system give PG values at least 50% larger than standard ones.

   This discrepancy is extraordinarily large so requires extraordinarily strong justification. The authors suggest some forms of measurement error, none of which are convincing, not least because they are unlikely to cause systematic error of this magnitude. Neither is it plausible that the actual PG at Zhongshan Station can depart so strongly from typical values, as the explanations given are questionable or just very vague ("geological conditions", "mostly ice and snow"?!). Previous measurements elsewhere in the Antarctic (which the paper failed to cite) show PG curves not very different from the Carnegie one, including the magnitude, e.g.: Deshpande, C.G. and Kamra, A.K., (2001) J. Geophys. Res., 106, 14207-14218; Reddell, B. D. et al. (2004) J. Geophys. Res., 109, A09308; Jeeva, K., et al. (2016) J. Geophysical Res. 121, 12-593.

   From the information given in the paper it is not possible to decide on the causes of the biases at Zhongshan Station and in Beijing, as insufficient details of lab calibration and the field mill installations, or their possible differences, are given. For example, the authors may not have taken into account the form factor of the installation, to correct for field distortion by the mast - this can in principle account for a two or three-fold discrepancy.

   In addition to missing detail, the meaning of some statements is unclear, for example: "Fair weather is in regions that are not strongly disturbed by weather or aerosols" (line 53), and other statements are questionable, e.g. why would "local geological conditions" impact the PG so strongly? The fact that "Beijing is densely populated" might lead to increased PG (due to pollution reducing atmospheric conductivity), not a value lower than at Zhongshan Station as found in the paper.  It is not the case that atmospheric electricity "data from Antarctica is rare" - see examples cited above, and many other publications.

   The list of references, in addition to important omissions, has been put together carelessly: formats are inconsistent and details such as volume numbers (or pages - sometimes it is impossible to tell), publishers etc. are frequently missing.

Reviewer 2 Report

The work is definitely of great interest. The measurement of the atmospheric electric field in Antarctica is an important addition to the network of measurements at other geographical locations. The work was done with high quality. Measurement methods and measurement conditions are described in detail. A comparative analysis with another measurement point was carried out. An interesting result is the daily course of atmospheric electricity in Antarctica, which does not coincide with the Carnegie curve. Even in Antarctica, local factors such as convection and turbulence are stronger than global factors.

Reviewer 3 Report

This paper reports observations of the vertical atmospheric electric field at a coastal Antarctic site. The account of the measurements and results are presented clearly, but there are few measurements; they cover only 12 days of fair weather and there is a great deal of scatter in the data.

There are serious problems in the interpretation of the results. The main problem is that they misinterpret the nature of the global electric circuit. Although the authors refer to many papers they do not seem to have understood them.

This misinterpretation shows up in the paragraph starting on line 233; “The conduction current near the ground is approximately a constant.” They then continue as if it is constant in time. Actually, the conduction current (Jz) in the atmosphere is approximately constant in altitude at a particular time and location, but varies with time during each day, as the overhead ionospheric potential (Vi) varies. The current density is given by Ohm’s Law, Jz = Vi/R, where R is the whole column resistance from the surface to the ionosphere at that location and time. In an atmosphere with negligible diurnal variation in convection, such as at the Antarctic stations of Vostok and Concordia on the ice plateau (Burns et al., J. Atmos. Sci., 74,783, 2017) or with oceanic measurements as on the sailing ship  ‘Carnegie’, (Harrison, 2013) the column resistance R is essentially constant during the day, and the application of Ohm’s law gives the diurnal variation of Jz as due to the diurnal variation of Vi,  which is just the well-known ‘Carnegie Curve’. This is a single peak - single valley curve as illustrated by Harrison (2013), and illustrated more precisely, month by month, by Burns et al., (2017). The ‘Carnegie’ diurnal variation of Vi applies globally, as has been understood now for a century. This is because the ionospheric conductivity is so high as to act as an equipotential, except for superposed dawn-dusk potential cells in the auroral zones due to magnetospheric currents. 

So it is incorrect to say (lines 53-55) that “Thus the fair-weather AEF is mainly related to the local air conductivity and aerosol content and content.” Actually, it is mainly related to Vi, and the presence of varying aerosol concentrations act only to perturb it from the diurnal variation of the Carnegie curve.   

So in figures 4 and 5 the main cause of the dominant single peak-single valley curves is the single peak - single valley Carnegie curve, with a maximum around 15-24 UT, and a minimum around 3-9 UT. Only the deviations from the Carnegie curve can be attributed to changes in aerosol concentration near the ground.

Such deviations are also well known, and the changes in aerosol concentration affecting the AEF, as described in this paper both in Zongshan and Beijing, appear to be the ‘Sunrise Effect’ that has been described many times in the literature.

It is not true (lines 94-95) that observations of the AEF from Antarctica are rare. The Antarctic Plateau is an excellent observational site for atmospheric electricity, and observations have been made over many years at the South Pole (1982-1986), at Vostok (1998-2001 and 2003- present) and at Concordia (2009-2011), as well as at the coastal sites of Davis and Maitri. So the 12 days of data from Zongshan add little to what has already been published.

The authors seem not aware that Zongshan is in the southern auroral zone, and thus the ionospheric potential there is influenced by the magnetospheric currents that raise the potential near dawn by about 25 kV for low magnetic activity, and depress the evening ionospheric potential by the same amount. This is important for precise measurements of AEF as on the Antarctic plateau, where vertical fields of 150-200 V/m are measured, but is less important for understanding the noisy 400 V/m data from Zohngshan.   

Another misconception is that the ionospheric potential, given as about 300 kV on line 33, is different from the potential from the top of the atmosphere to the ground, given as about 250 kV on line 37. They are the same potential.