Evaluation of the Vertical Distribution of Particle Shape (VDPS) method with in situ measurements and assessment of the impact of non-Rayleigh scattering

Teisseire, Audrey; Seifert, Patric; Ohneiser, Kevin; Maahn, Maximilian; Spirig, Robert; Henneberger, Jan

doi:10.5194/egusphere-2025-3923

Preprints

https://doi.org/10.5194/egusphere-2025-3923

Preprints

16 Sep 2025

| 16 Sep 2025

Evaluation of the Vertical Distribution of Particle Shape (VDPS) method with in situ measurements and assessment of the impact of non-Rayleigh scattering

Audrey Teisseire, Patric Seifert, Kevin Ohneiser, Maximilian Maahn, Robert Spirig, and Jan Henneberger

Abstract. In this study, the vertical distribution of particle shape (VDPS) method for retrieval of the vertical distribution of particle shapes and the identification of riming and aggregation processes is evaluated through comparison with in-situ measurements and co-located multi-frequency radar observations collected during the CLOUDLAB campaign in Eriswil, Switzerland. Additionally, a novel aspect of the VDPS method is introduced, enabling the derivation of the polarizability ratio using slanted-mode linear depolarization ratio (SLDR) calculated from the main peaks of the Doppler spectra of the signal-to-noise ratio (SNR) from the co- and cross-polarized channels, respectively. This enhancement allows for the detection of secondary ice production and the coexistence of multiple hydrometeor types, which would stay undetected when the retrieval is only applied to the main peak of the Doppler spectrum in the co channel. Finally, the susceptibility of the VDPS method to the effects of non-Rayleigh scattering (particle sizes close or larger than the radar wavelength) is examined. The obtained results were found to demonstrate the potential of the VDPS method using a Ka-band scanning cloud radar in SLDR mode for operational hydrometeor classification, even under non-Rayleigh scattering conditions.

Received: 11 Aug 2025 – Discussion started: 16 Sep 2025

Competing interests: At least one of the (co-)authors is a member of the editorial board of Atmospheric Measurement Techniques. The peer-review process was guided by an independent editor, and the authors also have no other competing interests to declare.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.

Download & links

Preprint (PDF, 17988 KB)

Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
Preprint (17988 KB)

Download & links

The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Journal article(s) based on this preprint

04 May 2026

Evaluation of the Vertical Distribution of Particle Shape (VDPS) method with in situ measurements and assessment of the impact of non-Rayleigh scattering

Audrey Teisseire, Patric Seifert, Kevin Ohneiser, Maximilian Maahn, Robert Spirig, and Jan Henneberger

Atmos. Meas. Tech., 19, 2897–2921, https://doi.org/10.5194/amt-19-2897-2026,https://doi.org/10.5194/amt-19-2897-2026, 2026

Short summary

Audrey Teisseire, Patric Seifert, Kevin Ohneiser, Maximilian Maahn, Robert Spirig, and Jan Henneberger

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2025-3923', Anonymous Referee #1, 09 Dec 2025

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-3923/egusphere-2025-3923-RC1-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2025-3923-RC1
- AC2: 'Reply on RC1', Audrey Teisseire, 25 Feb 2026
  
  Please upload the response letter as a supplementary file.
  
  Citation: https://doi.org/10.5194/egusphere-2025-3923-AC2
RC2:
'Comment on egusphere-2025-3923', Anonymous Referee #2, 07 Jan 2026
General Comments
This paper presents a validation of the VDPS method, introduced in an earlier paper by the same research group, expanding and illustrating its applicability to different case studies using independent VISSS observations recorded in the framework of the CLOUDLAB campaign. Two important contributions of the study are the use of SLDR based on cross-polarized Doppler spectra to detect hydrometeor populations and the assessment of non-Rayleigh effects trying to quantify biases at Ka/W band. Overall I think it is a valuable contribution to the field so, with a few clarifications and minor formal corrections (see Specific Comments), should be considered for publication – I suggest considering three general items in the text:
Authors could describe more explicitly the contribution of the SLDR approach used (why is it important).

The particle size limits considered as thresholds for Rayleigh scattering in the two bands used (Ka and W) could be mentioned in the introduction (not in a results section).

A brief discussion could be added on potential limitations of using ECMWF IFS temperature profiles instead of local measurements such as those obtained by tethered-balloons or from microwave radiometers (which in principle were also available during the campaign according to https://cloudlab.ethz.ch/the-project.html) – given the uncertainty associated to IFS profiles perhaps they could be plotted without one decimal digit as they are now.

Specific Comments
Page 1, line 9. Typo: co channel -> co-channel (as in the rest of the text)? Please check.

Page 2, line 43. Typo: Non-Rayleigh -> non-Rayleigh (as earlier in the same line and elsewhere).

Page 3, end of Section 1. Section 5, unlike sections 2 to 4, is not mentioned here; please add a sentence to briefly describe it (I think it is ok to omit Section 5).

Page 3, line 82. What does MBR mean? I assume is an internal naming convention, but readers might be curious (as I am) and a brief explanation can probably be added easily.

Page 4, line 90. Typo: 2016b)) -> 2016b)

Page 4, lines 98-99. ... of type (?)... Please check sentence and rewrite.

Page 4, lie 104. Format: Tab. or Table? Please be consistent – I suggest using Table.

Page 8, Figure 1 caption. Please add something as ‘Temperature levels plotted correspond to ECMWF IFS forecasts’ or similar.

Page 11, Figure 4 caption. 10:10:17 -> 10:10:17 UTC

Page 12, line 218. Please check meaning of this sentence. [and similarly Page 13, line 239].

Page 16, line 275. Typo: the presence supercooled liquid droplets -> the presence of supercooled liquid droplets

Page 23, line 405. ... that were... that was? Please check meaning.

Page 26, Figure 18 caption. Suggest: Surface hydrometeor shapes detected with VISSS ...

References: some DOIs have duplicated ‘doi.org’ strings in the URL.

Page 29, line 526. Typo: Journals -> Journal
Citation: https://doi.org/10.5194/egusphere-2025-3923-RC2
- AC1: 'Reply on RC2', Audrey Teisseire, 25 Feb 2026
  
  Please upload the response letter as a supplementary file.
  
  Citation: https://doi.org/10.5194/egusphere-2025-3923-AC1

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2025-3923', Anonymous Referee #1, 09 Dec 2025

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-3923/egusphere-2025-3923-RC1-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2025-3923-RC1
- AC2: 'Reply on RC1', Audrey Teisseire, 25 Feb 2026
  
  Please upload the response letter as a supplementary file.
  
  Citation: https://doi.org/10.5194/egusphere-2025-3923-AC2
RC2:
'Comment on egusphere-2025-3923', Anonymous Referee #2, 07 Jan 2026
General Comments
This paper presents a validation of the VDPS method, introduced in an earlier paper by the same research group, expanding and illustrating its applicability to different case studies using independent VISSS observations recorded in the framework of the CLOUDLAB campaign. Two important contributions of the study are the use of SLDR based on cross-polarized Doppler spectra to detect hydrometeor populations and the assessment of non-Rayleigh effects trying to quantify biases at Ka/W band. Overall I think it is a valuable contribution to the field so, with a few clarifications and minor formal corrections (see Specific Comments), should be considered for publication – I suggest considering three general items in the text:
Authors could describe more explicitly the contribution of the SLDR approach used (why is it important).

The particle size limits considered as thresholds for Rayleigh scattering in the two bands used (Ka and W) could be mentioned in the introduction (not in a results section).

A brief discussion could be added on potential limitations of using ECMWF IFS temperature profiles instead of local measurements such as those obtained by tethered-balloons or from microwave radiometers (which in principle were also available during the campaign according to https://cloudlab.ethz.ch/the-project.html) – given the uncertainty associated to IFS profiles perhaps they could be plotted without one decimal digit as they are now.

Specific Comments
Page 1, line 9. Typo: co channel -> co-channel (as in the rest of the text)? Please check.

Page 2, line 43. Typo: Non-Rayleigh -> non-Rayleigh (as earlier in the same line and elsewhere).

Page 3, end of Section 1. Section 5, unlike sections 2 to 4, is not mentioned here; please add a sentence to briefly describe it (I think it is ok to omit Section 5).

Page 3, line 82. What does MBR mean? I assume is an internal naming convention, but readers might be curious (as I am) and a brief explanation can probably be added easily.

Page 4, line 90. Typo: 2016b)) -> 2016b)

Page 4, lines 98-99. ... of type (?)... Please check sentence and rewrite.

Page 4, lie 104. Format: Tab. or Table? Please be consistent – I suggest using Table.

Page 8, Figure 1 caption. Please add something as ‘Temperature levels plotted correspond to ECMWF IFS forecasts’ or similar.

Page 11, Figure 4 caption. 10:10:17 -> 10:10:17 UTC

Page 12, line 218. Please check meaning of this sentence. [and similarly Page 13, line 239].

Page 16, line 275. Typo: the presence supercooled liquid droplets -> the presence of supercooled liquid droplets

Page 23, line 405. ... that were... that was? Please check meaning.

Page 26, Figure 18 caption. Suggest: Surface hydrometeor shapes detected with VISSS ...

References: some DOIs have duplicated ‘doi.org’ strings in the URL.

Page 29, line 526. Typo: Journals -> Journal
Citation: https://doi.org/10.5194/egusphere-2025-3923-RC2
- AC1: 'Reply on RC2', Audrey Teisseire, 25 Feb 2026
  
  Please upload the response letter as a supplementary file.
  
  Citation: https://doi.org/10.5194/egusphere-2025-3923-AC1

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload

AR by Audrey Teisseire on behalf of the Authors (25 Feb 2026) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (26 Feb 2026) by Raquel Evaristo

RR by Anonymous Referee #1 (09 Mar 2026)

RR by Anonymous Referee #2 (31 Mar 2026)

Suggestions for revision or reasons for rejection

General Comments

The corrected manuscript was improved but still there are some issues to be addressed.

In particular, regarding the IFS temperature, the evaluation was mostly qualitative. The text now discusses IFS limitations and mentions radiosonde checks but does not provide a quantitative comparison (bias / RMSE / timing mismatch). This matters where the interpretation hinges on the dendritic growth layer or 0 °C isotherm placement. I suggest adding a small table or figure or Appendix with IFS vs Payerne sounding (ΔT profiles, time stamps), and note any adjustments made to temperature contours (e.g., Fig. 1 removal rationale).

Formal aspects

1). In multiple places, the radar reflectivity uses spaced math like “Z e” instead of standard Z_e; likewise “v = −1 ms⁻¹” formatting alternates between different minus signs and spacing around “=”. This occurs across Sections 2–5 and figure captions. Please normalize to Z_e, DWR_{Ka–W}, SNR_{co} / SNR_{cross}, SLDR, and velocities as v = −1 m s⁻¹ (with thin space between unit symbols). Apply through text and figure axes/captions.

2). There is an inconsistent use of hyphen/en‑dash for “Ka‑band”, “W‑band”, DWR_{Ka–W}. Some instances use hyphen “-” and others an en‑dash. The subscript “Ka‑W” also appears as “Ka-W” or “Ka–W”. Authors should use Ka‑band, W‑band (non‑breaking hyphen) and DWR_{Ka–W} (en‑dash in the subscript) consistently.

3). Most acronyms are now defined, but a few first uses could still be tightened. Example: “RPG94 of type (RPG‑FMCW‑94‑DP)”—the parenthetical “of type” is awkward; also ensure VISSS and PeakTree (if mentioned) are expanded at first use in main text. Rephrase to “the RPG‑FMCW‑94‑DP (hereafter RPG94)” and ensure one clear first‑use expansion per acronym.

4). Most captions add “UTC”, but scan across figures to ensure all explicit times carry “UTC” and use a consistent hh:mm:ss style. E.g., Figs. 4–5, 9–10, 16–17 are mostly consistent; please do one final pass.

5). A few paragraphs narrate features in an order that differs from panel ordering (e.g., referring to SLDR before SNR panels). Readers have to jump back and forth. When discussing multi‑panel figures, follow a consistent order (e.g., SNR_{co} → SNR_{cross} → SLDR), according to the panel layout.

6). (Very minor). Note that authors use ‘Figure 1’ but later Fig. 2, etc. please be consistent.

Hide

ED: Publish subject to minor revisions (review by editor) (01 Apr 2026) by Raquel Evaristo

AR by Audrey Teisseire on behalf of the Authors (05 Apr 2026) Author's response Author's tracked changes Manuscript

ED: Publish subject to minor revisions (review by editor) (13 Apr 2026) by Raquel Evaristo

AR by Audrey Teisseire on behalf of the Authors (14 Apr 2026) Author's response Author's tracked changes Manuscript

ED: Publish subject to minor revisions (review by editor) (17 Apr 2026) by Raquel Evaristo

AR by Audrey Teisseire on behalf of the Authors (17 Apr 2026) Author's response Author's tracked changes Manuscript

ED: Publish as is (17 Apr 2026) by Raquel Evaristo

AR by Audrey Teisseire on behalf of the Authors (20 Apr 2026) Manuscript

Journal article(s) based on this preprint

04 May 2026

Evaluation of the Vertical Distribution of Particle Shape (VDPS) method with in situ measurements and assessment of the impact of non-Rayleigh scattering

Audrey Teisseire, Patric Seifert, Kevin Ohneiser, Maximilian Maahn, Robert Spirig, and Jan Henneberger

Atmos. Meas. Tech., 19, 2897–2921, https://doi.org/10.5194/amt-19-2897-2026,https://doi.org/10.5194/amt-19-2897-2026, 2026

Short summary

Audrey Teisseire, Patric Seifert, Kevin Ohneiser, Maximilian Maahn, Robert Spirig, and Jan Henneberger

Viewed

Total article views: 3,659 (including HTML, PDF, and XML)

HTML	PDF	XML	Total	BibTeX	EndNote
3,172	403	84	3,659	75	79

HTML: 3,172
PDF: 403
XML: 84
Total: 3,659
BibTeX: 75
EndNote: 79

Views and downloads (calculated since 16 Sep 2025)

Month	HTML	PDF	XML	Total
Sep 2025	2,582	44	12	2,638
Oct 2025	138	36	8	182
Nov 2025	70	24	16	110
Dec 2025	50	38	14	102
Jan 2026	204	68	18	290
Feb 2026	72	62	10	144
Mar 2026	52	123	6	181
Apr 2026	3	2	0	5
May 2026	1	6	0	7

Cumulative views and downloads (calculated since 16 Sep 2025)

Month	HTML	PDF	XML	Total
Sep 2025	2,582	44	12	2,638
Oct 2025	138	36	8	182
Nov 2025	70	24	16	110
Dec 2025	50	38	14	102
Jan 2026	204	68	18	290
Feb 2026	72	62	10	144
Mar 2026	52	123	6	181
Apr 2026	3	2	0	5
May 2026	1	6	0	7

Viewed (geographical distribution)

Total article views: 3,660 (including HTML, PDF, and XML) Thereof 3,660 with geography defined and 0 with unknown origin.

Country	#	Views	%

Latest update: 05 May 2026

Download

The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Preprint (17988 KB)
Metadata XML

Short summary

This study evaluates the vertical distribution of particle shape (VDPS) method for identifying particle shapes and riming/aggregation using in-situ and multi-frequency radar data from the CLOUDLAB campaign. Despite non-Rayleigh scattering effects, results show that the VDPS method using a Ka-band scanning cloud radar in slanted depolarization ratio (SLDR) mode is effective for hydrometeor classification.


Total:	0
HTML:	0
PDF:	0
XML:	0