Combined Raman Lidar and Ka-Band Radar Aerosol Observations

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1.Generally, radar is suitable for studying large particles such as clouds, dust, etc. Therefore, the author needs to clarify the error of aerosol scale parameters obtained by radar?

2.How to match the different field of view angles detected by lidar and radar for detecting the same atmospheric particles?

3.the inversion results by lidar shown in table B and C are almost the same, is it right? please check. 

Author Response

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Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript utilizes detection results of aerosols from lidar data and millimeter-wave cloud radar data to expand the retrieval range of aerosol microphysical parameters. The paper presents the methodology, detection data, and retrieval results. At first glance, the methodology appears reasonable. However, upon closer scrutiny, significant flaws in the paper's approach were identified. Therefore, the authors need to reconsider and revise the methodology. The main concerns are outlined below:  

• The manuscript proposes using lidar data to retrieve microphysical parameters of small-particle aerosols and millimeter-wave cloud radar data to retrieve microphysical parameters of large-particle aerosols13. However, when small- and large-particle aerosols coexist, the backscatter signal in lidar data will be dominated by scattering from large particles1. Under such conditions, lidar data cannot be effectively applied to retrieve microphysical parameters of small-particle aerosols1. Therefore, when lidar and millimeter-wave radar operate independently, ‌neither can independently retrieve microphysical parameters exclusively for small- or large-particle aerosols‌.
• The algorithm proposed in the paper for retrieving aerosol microphysical parameters relies ‌solely on two input variables‌: the radar reflectivity factor (Z) and linear depolarization ratio (LDR) from millimeter-wave cloud radar. ‌What magnitude of uncertainty‌ might exist in this algorithm?
  
  
• While the paper provides the ‌vertical profiles of aerosol layers‌ detected by lidar, ‌it fails to present corresponding millimeter-wave cloud radar detection results‌. The millimeter-wave cloud radar observations should be jointly presented to enable comprehensive comparative analysis

Author Response

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Reviewer 3 Report

Comments and Suggestions for Authors

This study synergizes Raman lidar and Ka-band cloud radar observations to extend aerosol detection capability up to 12 μm in particle radius (doubling the measurable size range compared to conventional lidar systems). By developing an inversion algorithm based on radar reflectivity and depolarization ratio, and applying it to a 6-year dataset from Potenza, Italy, we achieved the first successful co-retrieval of microphysical properties for coarse-mode aerosols. However, certain sections of the manuscript still require refinement. Please carefully consider and revise the content based on the following detailed suggestions: 

1. Instrumentation Section: For the lidar systems operating at 355 nm, 532 nm, and 1064 nm excitation wavelengths, please include details such as laser pulse energy, repetition rate, etc. If the laser energies are inconsistent, how are the resulting discrepancies in detection signals compensated for or corrected?
2. Cloud Radar Observations of Aerosols: At higher atmospheric altitudes, even if an insect layer exists, its population would be minimal compared to the order of magnitude of aerosols. Is such a classification reasonable?
3. Aerosol Effective Radius and Microphysical Properties: Retrieving these parameters solely from radar data and scattering matrices may introduce significant deviations from true values. Are there other observational datasets (e.g., sun photometer measurements, aircraft in-situ sampling) available for validation?
4. Table 6: The discrepancies in aerosol microphysical properties derived from radar and lidar are considerable. Should the wavelength dependence be discussed here?
5. High-Altitude Aerosols: The influence of ice crystals, mixed-phase clouds, etc., should be considered. The scattering database used in the study does not include ice-nucleating particles or bioaerosols, so it should be clarified that the results are applicable only to mineral/volcanic ash aerosols.
6. Synergistic Use of 355/532/1064 nm Lidar Data: How exactly are these multi-wavelength lidar data integrated and utilized in the retrieval process?
7. Generalizability of Results: All data are sourced from the Potenza site in Italy. Extending the conclusions to other climate regions requires caution. It is recommended to include additional observational examples from other climate zones (e.g., from literature or other research teams).

Comments for author File: Comments.pdf

Comments on the Quality of English Language

The overall grammar is very good. Please review it carefully again, author.
However, the overall word count of the article is too long and needs to be refined and reduced

Author Response

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Reviewer 4 Report

Comments and Suggestions for Authors

General Comments: (overall quality)

This paper presents an innovative method for characterizing giant aerosols in terms of optical and microphysical properties, using a complex synergy between observational data from lidar and radar, combined with atmospheric transport model (FLEXPART). Although the method proposed in this paper uses only remote sensing measurements taken during the night (due to the limitation of lidar systems), the obtained results demonstrate the ability of the method to estimate the microphysical properties of giant aerosols.

Great contribution, should be accepted after minor revision. Also, the paper is well written, carefully prepared, and well structured.

Specific Comments:

Introduction

Page 2 line 57: “great distances from their sources” change to “long distances from their sources”

Results

A graph (or a table) and a brief description of how these results can improve climate models would also be useful to the scientific community.

Figures 5 and 8: I recommend adding error bars for all profiles shown in these figures.

Author Response

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Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have revised fully.

but I hope to see more results by combined measurements in the future.

Author Response

Comments 1: The authors have revised fully.

but I hope to see more results by combined measurements in the future.

Response 1: Thank you for checking, we will be working on it.

Reviewer 2 Report

Comments and Suggestions for Authors

1. In the introduction, there is no current status or progress in inverting aerosol microphysical parameters. It is recommended to supplement this. Numerous researchers have conducted studies on the retrieval of aerosol microphysical parameters.

For Example:

• Huige Di, Yun Yuan, et al. 2024, Optics Express.
• Mueller， 1999， Applied Optics.

 

2. It is recommended to adjust the color of the color bar in Figure 3 (a), as the current color makes the aerosol layer appear unclear.
3. The description of P367-P385 is inconsistent with the one shown in the figure. The two layers of coarse aerosol observed in Figure 5 are located at 1-2km and 2-3km.
4. It is recommended to adjust the paper structure by presenting the analysis results of microphysical parameters immediately after displaying the direct detection results of each case. This approach will facilitate more coherent reading and comprehension for the readers.
5. The author conducted inversion of microphysical parameters targeting ‌which vertical layer measured by radar‌? Why are microphysical distribution characteristics ‌at different heights‌ absent from the results, given that ‌distance resolution constitutes radar's core advantage‌?
6. The authors utilized lidar and millimeter-wave radar to retrieve the fine-mode and coarse-mode particle spectra distributions in aerosols, respectively. In the retrieval outcomes, overlapping data appears in the transition region between the two sets of results. For particle distributions within this overlapping size range, which dataset should be considered more reliable?

Author Response

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Reviewer 3 Report

Comments and Suggestions for Authors

Reviewer Comments :

Having carefully reviewed the manuscript revised in response to the previous round of review comments, I confirm that the authors have adequately and effectively addressed all major concerns and revision suggestions raised by the reviewers. The manuscript demonstrates significant improvements in scientific rigor, logical coherence, clarity of presentation, and compliance with formatting standards. The revised version now fully satisfies the journal's requirements for publication.

During final proofreading, please ensure thorough checking of:  (1) Consistency in English terminology, and  (2) Reference formatting. 

Author Response

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