Review for the AMT-Discussion paper - https://doi.org/10.5194/acp-2021-177

1) general comments

The paper deals with lidar measurements to improve the understanding of microphysical process of mid-level stratiform clouds. The results of this study are based on two case studies observed in 2017 and 2019. The authors also highlight, that lidar observations of precipitating cloud systems where the whole precipitation process can be studied are rare but needed to understand the process from origin till rain hits the ground

The data are obtained by two lidar systems, a depolarization and a water vapor Raman lidar. The radar systems are designed to be able to measure also during light rain – optics of the systems are protected by a glass window in the roof of the institute.

The measurements depict two warm front cloud systems overpassing the measurement site. These lidar observations are described and related to precipitation formation processes. While the liquid microphysical processes seam to dominated the analysis.

Generally, the structure in the paper is not clear enough. The result section 3 is missing a red line to follow. It might be helpful to make more paragraphs and structure them better. It is not always easy to connect the information with the actual microphysical processes observed. So having more explanation of what process is happening and explain the resulting observation signatures would help. Perhaps use a sematic sketch? If this could be improved the quality of the paper would rise for sure.

2)    specific comments

• Section 2.1. line 73-75 and section 2.1.1 line 111-114

Are there data or plots available to show the results of the water splashing experiment? From my site the performed technique is new, so results of it should be presented or at least citations given to similar performed experiments.

• Section 2.1.1 line 103-108

The explanation of the dark band is hard to follow. Could you split the sentence into two or 3 parts and extend the explanation a bit so that it is better to read?

• Section 3.1. Figure 1

The text below the Figure is too long. Describe what the graphs show, do not give any interpretation or highlight things the graphs show the caption. All interpretations or highlights that can be seen have to be in the main text of the article

• Section 3.1.1 sentence line 160-160 and following sentences

I had a hard time to follow the text here and connect the information you give to the story you want to tell. Please structure this paragraph clear. What can be seen in the graph and what do you follow from your observations. Perhaps make some paragraphs to give the text more structure.

• Section 3.1.2 line 201-204

This explanation has to be given when you explain the water splashing experiment! So move this up in the section above!

• Section 3.1.2 line 210-211

Can you explain these in more detail or give a citation? Is there a relation to the signature and the distance to the 1km or higher origin layer of the initiation? Can signatures be used to identify the high of initiation?

• Section 3.1.2 paragraph 4 (234-243)

Can you explain this in more detail? Are there other observations done showing the same, give a citation? It would be nice to get a bit more explanation for people not so familiar with lidar measurements

• Section 3.1.2 line 306

Does this comparison make sense here? 1 mm large super cooled droplets? Could you comment on this please and give a reference!

• Section 3.1.2. line 313-325

This pat was hard to follow. It might be one of the mature parts of the paper. Please, describe what you observed and in a second step what process might be behind. Perhaps it makes also sense to make a summarizing sketch of the processes observed and relate them to the measurements you would expect. Then it is easier to follow for the readers.

3) Technical corrections

• Line 216-218: Please reformulate this sentence
• Please have a clearer structure in your sections and paragraphs
• Make more paragraphs
• Shorten you captions of the figures; some are quite long. Put the information into the text or make more figures

The manuscript reported on the microphysical processes of precipitating hydrometers that occur at altitudes ranging from the parent cloud base down to the near surface for two warm-frontal precipitation episodes. The results are based on the simultaneously observed sequential profiles of the range-corrected signal X, volume depolarization ratio v and water vapor mixing ratio qv from the combination of a 355-nm polarization lidar and water-vapor Raman lidar at Wuhan University atmospheric observatory. The observational period ranges clear-sky, cloud to precipitation, allowing for the process analysis. The observational result could potentially contribute much to the application of convection forecast. More importantly, something interesting is revealed for the first time for both light and moderation rainfall from warm-front mid-level stratiform clouds in Wuhan, Central China. To minimize of the water accumulation impact of lidar roof window on lidar signals, the authors conducted an artificial water splashing experiment, showing promising results for its height-independent lidar signal. The observational methodologies are novel, and the analysis seems scientifically sound to me. Therefore, findings are convincing and deserve rapid acceptance for publication at ACP. Nevertheless, fruitful discussion regarding the warm front is still lacking. Besides, there are other minor issues that need to be addressed prior to formal acceptance, which are listed as below:

Major comments:

1. WARM FRONT:  More discussion is required. Except for the prevailing wind, a variety of other meteorological variables can be used to characterize the warm front, including air pressure level, the temporally varying cloud properties. For instance, when a warm front is approaching, the barometric pressure begins decreasing,  the wispy and high cirrus clouds appear. Then, the layer of clouds tends to thicken along with raindrop falls from the cloud base as it arrives, meanwhile, nimbus, cumulus, and stratus clouds can be observed. Generally, the precipitation associated with the warm front is light and steady, and thus its intensity is moderate, and can last for several days. Under some special conditions, the warm fronts also accounts for the thunderstorms and intense precipitation. Alternatively, to better illustrate of the two warm-front rainfall cases, the authors may take a look at the composite synoptic map showing surfacee-level geopotential height and surface potential temperature, in which the warm front is supposed to be marked.

2. Verification of LiDAR-measured cloud layer is of importance to the result interpretation, since most of the results presented here are from LiDAR. Given the availability of simultaneously observed radiosonde during both case studies, the authors may make a compare analysis of cloud layers from radiosonde and LiDAR based on the RH threshold methods. This will enhance the readership of this work, in my point of view.

Minor comments:

1. L60-63: “An artificial water splashing…. was altered” reappears in L110-114, which seems redudant and one can be kept.

2. L92: “Based on a method developed by Newsom et al. (Newsom et al., 2009; Zhang et al., 2014), ” can be rephrased as “Based on a method originally proposed by Newsom et al. (2009) that was further developed by Zhang et al. (2014),”

3. L122: “A comparison” -> “A comparison analysis”

4. L134: “Nash 2011” -> “Nash et al., 2011”

5. L136-137:  More details about the measurements by tipping-bucket rain gauge are suggested to be added, such as the sampling intervals or frequency.

My comments are attached.