Research on small-scale structures of ice particle density and electron density in the mesopause region

Tian, Ruihuan; Wu, Jian; Ma, Jinxiu; Liang, Yonggan; Li, Hui; Yuan, Chengxun; Jiang, Yongyuan; Zhou, Zhongxiang

doi:https://doi.org/10.5194/angeo-37-1079-2019

Articles | Volume 37, issue 6

https://doi.org/10.5194/angeo-37-1079-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/angeo-37-1079-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 37, issue 6

Regular paper

|

05 Dec 2019

Regular paper |

| 05 Dec 2019

Research on small-scale structures of ice particle density and electron density in the mesopause region

Ruihuan Tian, Jian Wu, Jinxiu Ma, Yonggan Liang, Hui Li, Chengxun Yuan, Yongyuan Jiang, and Zhongxiang Zhou

Download

Final revised paper (published on 05 Dec 2019)
Preprint (discussion started on 05 Mar 2019)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

- Printer-friendly version

- Supplement

RC1: 'Review of ‘The research on small-scale structures of ice particle and electron density in the mesopause region’ by Tian et al.', Anonymous Referee #1, 12 Apr 2019
- AC1: 'Response letter', Ruihuan Tian, 26 Jun 2019
RC2: 'The research on small-scale structures of ice particle density and electron density in the mesopause region', Anonymous Referee #2, 22 Jun 2019
- AC2: 'Response letter', Ruihuan Tian, 26 Jun 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (further review by editor and referees) (18 Jul 2019) by Andrew J. Kavanagh

AR by Ruihuan Tian on behalf of the Authors (22 Jul 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (23 Jul 2019) by Andrew J. Kavanagh

RR by Anonymous Referee #1 (23 Jul 2019)

Suggestions for revision or reasons for rejection

Review of the first revision of ‘The research on small-scale structures of ice particle and electron density in the mesopause region’ by Tian et al.

The authors have made significant revisions to the original manuscript (particularly the ionospheric plasma model) that have strengthened it significantly. They are to be credited/acknowledged for this. However, the prime issue with the first revision still exists. The authors have not made a persuasive case of the advance made by this work relative to other work in the field. This is not clarified in the Abstract, Introduction, or most importantly, the Conclusions section. Therefore, the manuscript is still not worthy of publication in its current state until this critical issue is addressed through further major revisions. Some examples of this inadequacy are as follows:

1. Abstract: The authors do not note the uniqueness or novelty of the growth model. Is it the first of its kind or an advance over previous models? This must be clarified to make the case that this is work suitable for publication in Annales Geophysicae. The last few sentences state the results of applying the plasma model to the neutral density obtained with the model. The conclusion is correct, but is it also well known by a number of previous investigations (both modeling and data). Again, the question arises what is the novelty or contribution of the work. The reader is again brought back to the fact that the neutral model (and incorporating it into the plasma model) is most likely the primary contribution of the manuscript. However, this is poorly articulated and a persuasive case not made.

2. Introduction: The authors state near the end of the Introduction that ‘this study is trying to explain the formation of these ice particle irregularities through a growth and motion model.’ Is this model new? If so, how is it different from past work ? How does the new model allow the authors to solve an unknown critical problem in the field? Why is this problem important in the grand scheme of advancing the state-of-the-art in the field. Also how does incorporating this (possible new) neutral model into the ionospheric plasma model (which is the same as past models) facilitate resolution of important unresolved issues in the field. Without such a clarification, no persuasive case has been made on how the work is novel.

3. Conclusions: The Conclusion section also does not make a persuasive case of the novelty of the work. The first paragraph, for the most part, just reiterates the model. The second paragraph should make the case for novelty of the overall contribution. It is stated ‘When the radius distribution function of condensation nucleus is Gaussian, stable small-scale ice particle density structures can be obtained based on the growth and motion model.’ Is this the primary contribution ? If so, why is it important? Has this already been known before or have other models been able to produce this result? It is also stated ‘Furthermore, the reduction of electron density and the increment of ion density are about half the charge number density of ice particles, which is in line with the results under diffusion equilibrium approximations.’ Why is this important ? Has it been shown with other models before ? To reiterate, it is very difficulty to understand the contribution or importance of the work from the Conclusion section.

4. Figure 3 and 6: Do these two Figures perhaps show the primary overall contribution of the work? Is the contribution the utilization of the overall model (neutral and ionospheric plasma when used together) that happens to produce results of electron fluctuations (both spatial scales and amplitudes) in line with experiments ? If this is the case this needs to be carefully clarified to help address the issues raised in 1., 2., 3. Also, has the parameter regime used in Figure 3 and 6 been explored to perhaps provide a more novel contribution on unresolved questions?

In overall summary, the authors again have not made the persuasive case (although it may exist) of the novelty of the work to the degree the manuscript warrants publication. They should be commended on greatly improving the ionospheric plasma model, however, this is now just equivalent to past work.

Hide

ED: Reconsider after major revisions (further review by editor and referees) (25 Jul 2019) by Andrew J. Kavanagh

AR by Ruihuan Tian on behalf of the Authors (14 Aug 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (26 Aug 2019) by Andrew J. Kavanagh

RR by Anonymous Referee #1 (28 Aug 2019)

Suggestions for revision or reasons for rejection

The authors have made further useful revisions on the manuscript. However, there are three further important points the authors must carefully consider and address before the manuscript is suitable for publication.

First Point: There is still the question if the work is novel. As underscored (more clearly) by the authors in the current revision of the manuscript, the particle growth model is the primary novelty. However, the ultimate result of this work is to show if the electron density structures produced with the new particle growth model are in line with experiments and can provide further insight into the process producing PMSE. The results of the author’s work conclude that meter scale electron irregularities are produced which is already well known and the question again arises if the work is novel. For instance, could other models produce meter scale irregularities? As noted in the second review (point 4), the authors need to consider if there are some parameter regimes that their current particle growth model can explain that other models cannot. A simple thing to do is to consider what parameters in the growth model controls the spatial scales of the irregularities. The authors should note that the work of Lie-Svensen considers a relatively broad range of spatial scales of irregularities from meters to 10’s of meters (using a prescribed aerosol particle density). This is of course motivated by PMSE being observed at a range of frequencies (e.g. UHF, VHF, MF, and HF) and altitudes. An important question is what actually causes the variation in spatial scales in electron structures (and the associated aerosol structures calculated with the new growth model). Are the spatial scales related to wind velocity or altitude for instance. Examples (and related work) are Bremer et al., PMSE observations at three different frequencies in northern Europe during summer, Annales Geophysicae, 1996 and Acala et al. Multifrequency observations of polar mesosphere summer echoes using alaskan radar facilities: Comparisons and scattering calculations, Radio Science, 2009.

To reiterate, the authors should consider which parameters in the new growth model can determine the spatial scales of irregularities (as noted in point 4. Of the previous review). Is this the wind speed for instance ? Also, what is the impact of altitude on the spatial scales of the irregularities? Can this be determined with the new growth model? Are longer or shorter irregularities produced as the altitude varies. These are all important questions that could potentially be answered with the model and be impactful to the community.

Second Point: The authors use the term ‘stochastic model’ for the charging. Are the authors confident they are actually using a stochastic model? This would imply using a probability model to determine the discrete charging state. It may be more appropriate to describe this as a ‘discrete charging model’ (as opposed to continuous charging) and not a stochastic model. The Lie-Svensen model uses a discrete charging model not stochastic.

Third Point: There are still lots of issues with English language and typographical errors. The manuscript must be more carefully edited.

Hide

ED: Reconsider after major revisions (further review by editor and referees) (09 Sep 2019) by Andrew J. Kavanagh

AR by Ruihuan Tian on behalf of the Authors (13 Oct 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (24 Oct 2019) by Andrew J. Kavanagh

RR by Anonymous Referee #1 (25 Oct 2019)

ED: Publish subject to technical corrections (25 Oct 2019) by Andrew J. Kavanagh

AR by Ruihuan Tian on behalf of the Authors (02 Nov 2019) Author's response Manuscript

Short summary

The density distribution of ice particles and electrons near the boundary of the polar mesosphere summer echo (PMSE) region is studied. The results show that when the radius distribution function of the condensation nucleus is a Gaussian type, for a certain range of the condensation core radius, sharp peaks with a meter scale appear in the density profiles of ice particles and electrons. These small-scale structures of electron density may be one of the causes of the PMSE phenomenon.