the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Measurement report: Rocket-borne measurements of heavy ions in the mesosphere and lower thermosphere – Detection of meteor smoke particles
Abstract. We present data from flights of two improved ion mass spectrometers in the mesosphere and lower thermosphere region. The instruments were optimized to detect large ion masses of up to m/z 2000 and 20000 respectively, for analysis of meteor smoke particles. The flights were performed in the frame of the PMWE campaign, initiated and coordinated by IAP/Kühlungsborn, to investigate polar mesospheric winter radar echoes in Andøya/Norway in 2018 and 2021. Both flights were successful and allow to investigate the mass number and chemical composition of charged meteor smoke particles. We found a complex and divers composition of positively and negatively charged molecules and particles. While at altitudes below 85 km we observed negatively charged particles of up to several thousands of atomic mass units, above this altitude we found possible building blocks of these large particles that form right after their ablation from the parent meteorite material. While in the first flight we detected no positively charged molecules and ion clusters above m/z 100, we measured positive and negative ions with masses up to around m/z 400 in the second flight. Due to the very large mass range of m/z 20000 used in the second flight and the subsequent lower mass resolution, unambiguous mass identification is not possible. Comparing our findings to proposed meteor smoke particle compounds by other authors, our observations would be consistent with Magnetite, Fayalite and Forsterite. However, other possible compounds cannot be excluded.
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RC1: 'Comment on egusphere-2024-1631', Anonymous Referee #1, 25 Jun 2024
This paper on mass spectrometric measurements of heavy ions in the meteor ablation zone adds considerably to the little that is known. On of the authors discovered these many years ago and this builds on that legacy. The paper is well written and applicable to a variety of atmospheric questions and should be published after minor revision. I have two points that will improve the paper slightly and a few grammar type corrections.
The altitude vs mass graphs include a lot of dark blue points. These seem to be ignored in some of the description. I am guessing because they are thought to be noise in the multiplier but I didn’t see this description. The authors should be addressed by a short description of what is signal and what is noise.
These types of particles have been proposed to be part of a cycle that leads to meteor radio afterglows. A sentence or so mentioning this important is probably appropriate. Association between Meteor Radio Afterglows and Optical Persistent Trains, K.S. Obenberger, J.M. Holmes, S.G. Ard, J., Dowell,, N.S. Shuman, G.B. Taylor, S.S. Varghese, and A.A. Viggiano J. Geophys. Res. 125 10.1029/2020JA028053 (Sep 2020).
Page 5. Define PFTBA
Page 5, Table 2, RF Voltage maximum, not RF voltage since it is variable.
Page 9, beginning of rocket launches. I don’t know what a mesospheric winter echo is, so it should be defined.
Page 17, line 19 line 247, smoother not more smooth
First paragraph of summary. Divers is twice mentioned – should be diverse.
Citation: https://doi.org/10.5194/egusphere-2024-1631-RC1 -
RC2: 'Comment on egusphere-2024-1631', Anonymous Referee #2, 30 Jun 2024
This paper is a comprehensive presentation and analysis of recent observations of positive and negative ion mass spectra in the polar D and E region using a new cryogenic quadrupole mass filter based on a former, established design. The main objective are in situ studies of the composition of meteoric smoke particles (MSP). The authors suggest the detection of several positive and negative species, mostly containing Fe (iron), in line with models and some previous observations.
The results are based on only two flights, including some inconsistent results between the flights. More flights and further instrumental improvements should be pursued to confirm the composition altitude structure. Nevertheless, the paper is an important new contribution continuing several decades of D region ion and heavy ion measurements.
In this context I recommend to add Chesworth, E.T. and Hale, L.C. (1974), Ice particulates in the mesosphere. Geophys. Res. Lett., 1: 347-350. https://doi.org/10.1029/GL001i008p00347 as an example and review of earlier work on mesospheric heavy ions (not only icy aerosols), even though these were not all mass spectrometer measurements.
I recommend publication in its present form after some minor fixes and clarifications.
The paper is well written, however, there are some typos and other errors. I recommend using a good spell and grammar checker. A few sentences were unclear (for me or a general reader); they can be rewritten to improve the general flow and understanding.
L.3. frame —> framework
L.3. PMWE introduce acronym
L.4. IAP introduce acronym
L.5 allow —> allowed
L.6. divers —> diverse
where is the significant result? key points? This could be made stronger in the abstract.
L.20. an (duplicate)
L.20. DLR introduce acronym
L.20. MPI introduce acronym
L.21. LMU introduce acronym
L.22. 1980s
L.25. ions,
L.28. the instrument in detail
L.88. usec —> µsec
L.100. the mass scan increases (no comma)
L.100. negative steps in the count rate: unclear, what does this mean? the count rate drops?
L.107. PFTBA introduce acronym
L.109. ROMARA-1, but to … extent.
L.115. what is a “cone distribution”?
L.121. capitalize Mode A, Mode B
L.145. mode —> modes
L.171. unclear: what negative measurement slots? I think the white gaps in Fig. 6, but can be clearer
L.181. to explain the NO+/O2+ peak; what was the total plasma density in R-1 and R-2, from other instruments?
L.191. too sensitive for the prevailing … what does this mean? Need some kind of transition to the explanations that follow.
L.191. where is the cap ejection in Fig. 8?
L.193. how can one see the payload spin at m/z 460 in Fig. 8?
L.201. paralyzed = saturated?
L.213. why is this unexpected?
L.238. It might be helpful to reproduce a model of expected ion species from MSP here, so that the reader has a reference
L.242. Despite that …
L.259. To begin with, (comma)
L.268. “high probability” according to the measurements (interpretations?) by Hervig
L.273. At this time … this sentence is unclear, should be rewritten, this goes back to the explanation of spin signal in the spectra
L.294. diverse —> ambiguous?
L.296. ca. —> about (circa is in English c., not ca.)
L.298. diverse
L.304. —> his proposed “magnetite, …”
L.305. or deny —> nor reject
L.308. MLT region (no hyphen)
L.311. How quantitative are these total charged particle profiles? As mentioned above a comparison with an absolute electron density or positive ion density profile measured on the same payload would be helpful.
L.330. add some commas or semicolons in this listing of authors
Citation: https://doi.org/10.5194/egusphere-2024-1631-RC2 -
RC3: 'Comment on egusphere-2024-1631', Anonymous Referee #3, 12 Jul 2024
This manuscript reports the in-situ measurements of charged nanoparticles/heavy ions in the mesosphere/ lower thermosphere during two rocket flights. These are important results for research into the upper atmosphere/ionosphere because there are only few in-situ measurements of this kind. The measurements are presented appropriately. However, an evaluation of the presented measurements regarding the scientific discussion in the field is missing from the manuscript. The authors ignore theoretical work and model calculations from recent years that deal with the size and distribution of meteoric smoke particles. The connection with meteors should also be presented - albeit briefly.
The reader is left with the question how the presented work connects to the current knowledge in the field. The authors seem to refer to the “meteor smoke” as discussed in the literature, but do not adequately describe what is meant by this (One small but confusing thing is that other works use the term “meteoric smoke.”). Furthermore, the terms “clusters” and “heavy ions” are used. A comparison of the obtained results with the particle sizes and masses used by other authors is missing. This is applicable at least for the high mass numbers and it would allow the reader to assess the results in comparison to other works. The title of the manuscript seems to imply that "meteor smoke particles" are heavy ions. Water clusters are also mentioned. How are all these components connected? Theoretical works on meteoric smoke formation often start from an initial size of 0.2 nm: based on the presented measurement, can you support this assumption? How do the results link to other parameters measured during the same rocket flights? And finally, what does all this have to do with PMWE?
The manuscript needs major revision before being published in ACM.
Minor revisions and language corrections are also recommended. Points for minor revisions were also given already by other reviewers, some are given below:
line 1: we present data from “rocket” flights
line 10: m/z not defined in abstract, not defined when first used in text
line 14: ablation takes place over a height interval and the forming particles are carried in the atmosphere – please expand and provide references
line 20/21: write out or define LMU, IAP, DLR
line 39: give reference for existence of water clusters
section 2.1: table 2 is not mentioned in the text – please also check whether all figures and tables are refered to in the text
line 96: rephrase sentence: “The result is a spectrum…”
data access: there is a link given for the data, but access does not work - possibly because of a lack of documentation
Citation: https://doi.org/10.5194/egusphere-2024-1631-RC3
Data sets
PMWE1F-ROMARA Joan Stude, Heinfried Aufmhoff, and Markus Rapp https://doi.org/10.5281/zenodo.11470114
PMWE2F-ROMARA Joan Stude, Heinfried Aufmhoff, and Markus Rapp https://doi.org/10.5281/zenodo.11469720
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