A Comparative Study on the Vertical Structures and Microphysical Properties of Stratiform Precipitation over South China and the Tibetan Plateau
Round 1
Reviewer 1 Report
Remote Sensing - 1271349
A Comparative Study on the Vertical Structures and Micro-2 physical Properties of Stratiform Precipitation over South 3 China and the Tibetan Plateau
By Jingshu He, Jiafeng Zheng, Zhengmao Zeng, Min Zheng, Jianjie Li and Yuzhang Che
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General comments:
This paper proposes to compare stratiform precipitation (SP) bright band (BB) and precipitation characteristics from two sites equipped with K band MRR and Ka band MMCR radars, one in southern China and the other on the Tibetan plateau. To do so, they first describe their BB identification methodology, calculate the BB altitude and extend, then compare the precipitation radar echoes and corresponding drop size distributions below.
The paper has potential and is fairly well written. Nonetheless, there are places where more precise wording and/or phrasing would improve the manuscript readability. Furthermore, and more importantly, some arguments need to be further developed in order to bring out the full significance of the article.
Specific comments:
L 49-51: Sentence is rather awkward: not all SP precipitations exhibit a bright band… it is a matter of temperature and vertical extend of the cloud. As presented, the argument is misleading.
L 51-53: A reference to this well-known property could be useful here anyway
L 53-55: Again, the sentence is a bit awkward… your argument is true for a meteorological radar when measurements aloft within the BB are used to estimate the ground precipitation… but the BB will not affect the surface QPE when observations are made below the BB (but for attenuation effects)
L 59 + L 68: References should be provided with their listing numbers
L 59-72: The work of Foth et al, 2020 should also be considered in this section
L 73-76: The reference article by Rosenfeld and Ulbricht (2003) must be considered here as it lays the basis of such DSD evolution understanding work as the one you propose. Likewise, the application presented in Zwiebel et al. (2015) is also very relevant to your work… Not mentioning these two significant references with regards to your work seems a major oversight.
L 111-114: You should address the scientific objective underlying your work beyond a mere comparison.
L 167: This is a very good description of Ka-MMCR data processing… why isn’t there a similar point on K-MRR and PD processing and data control?
L 205-208: It appears to me as a reversed argument which is thus misleading. The reference papers cited state that the BB (or melting layer) is much easier to detect and define in SP… but they never ruled out the fact that BB can appear in non-SP events such as in convective events: the lack or difficulty of detection does not mean it does not exist. Hence, your argument stating that BB signature is equivalent to SP is a bit abusive, strictly speaking.
L 220-226: Sentence is not very clear… overall, I feel your description of the method could be improved to clarify its understanding.
L 245: “Confidential” … I suppose you meant “robust”.
L 260: When expressing rain accumulation levels, you must precise over what time period, or you should use rain rate figures.
L 305-307: As presented the argument has little interest. You should consider slopes of variations per km of altitude. Furthermore, how do you interpret the different behaviors between LM and NQ for Ze and Vm, as, i.e., Ze’s are similar at top of ice clouds for both sites, while Vm’s are similar at bottom of ice clouds (top of BB)?
L 307 and after: Looking at Figure 4 it is hard not to consider that the melting layer effect on the radar profiles extend to the ground for NQ, making the argument very questionable, while it is further admitted that the reflectivity measured in the lower range gates of such radars is sometimes not fully accurate! This should be discussed, while figure 4 seems also to be contradicted by your statistical results positioning the BB at more than 950 m of altitude and its bottom above 700m for NQ: this seems difficult to reconcile visually so you should discuss these points to consolidate your arguments and results.
L 321: “both”??
L 321: “positive velocities”, that is in panels 5 because in panels 2 they are negative (so why change sign between the 2?) … but if I am mistaken, then I guess the sentence isn’t really clear.
L 321-322: You should develop your arguments on how you can infer the vertical air motion from your data, how robust that interpretation is, and why then it is not accounted for while it might prove significant in later microphysical interpretations!
L 326: your last sentence needs at least a comment or, better, an interpretation as a science article should go beyond mere descriptions of figures.
L 343: Explain how or why? Furthermore, similar Vm’s at the top of the BB (Fig. 4) could mean that particle sizes are identical at both sides… which goes against your non-demonstrated claim.
L 375-376: “consistent” might not be the best term.
L 377: Wouldn’t attenuation show better on Ze’s rather than on Vm’s?
L381-382: You need to explain how you can draw such conclusions, based on what arguments?
Table 3: What about Ka-MMCR Ze and Vm?
L399 and following: You should definitely consider looking into the vertical evolution of the DSD (as in figure 9) with decreasing altitude along the whole rain falling process in order to clarify and reinforce your arguments.
Likewise, and this is a more general comment, you might want to consider altitudes not in absolute values but as a distance from the BB level when comparing the two sites.
L 406: “decreases”???
L 409: I do not agree. To me, it seems that for 1 mm rain drops there is first a decrease below 1.6 km, before an increase later down. Actually, how do you interpret the drops behavior at the 1 km level in ML?
Figure 7a: The little “spike” for the smallest drops at the 1.6 km is puzzling as it is not correlated with any feature in Figure 8 (a-c)! How do you account for this discrepancy?
Figure 9: As stated earlier, you should definitely discuss you results in the light of the work by Rosenfeld and Ulbricht (2003) and Zwiebel et al. (2015). To me the LM evolution is a clear sign of concurrent coalescence and break-up processes, while the NQ evolution corresponds to coalescence while there is, apparently, no sign of evaporation in the DSD spectra changes with altitude. I am not rebuking your statements, but I need somewhat more precise arguments and clearer demonstrations to be convinced.
L 453-462: Please explain the reason for such observed different behaviors based on microphysical processes at play.
L 470-473: You should provide here explanations or at least hypotheses that sustain your findings.
L. 494-498: This sentence is mainly inconclusive. Is realy altitude difference and topography the only factor at play?
L 499-501: OK… but that was not really discussed in the text while this does not seem evident in the PD diagram of Figure 10d.
L 509: The conclusion chapter will benefit from a revision in light of the suggested analysis improvements.
L515-516: a somewhat awkward sentence. You should better describe the cause and effect relationship at play and how they differ at each site.
L 525: “diverse microphysical processes”: which ones? This is definitely too unspecific: conclusions should bring out significant results.
L539-540: These claims were not precisely demonstrated in the prevailing analysis.
Conclusions:
This paper shows clear potential, but one would definitely appreciate more precise and in-depth analysis, looking both at the DSD variation along the whole fall of the hydrometeors to determine the microphysical processes at play, and at the relative altitude with respect to BB to determine if it is indeed altitude the only impacting factor on rain characteristics on the ground.
Thus, it the reviewer’s opinion that this paper will benefit from a major revision to allow to pursue and bring to significant results and conclusions the work provided.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this manuscript, author tried to study the statistical characteristics of bright band center, top, and bottom heights, corresponding radar parameters, and microphysical properties of summer season stratiform precipitation over high altitude (Nagqu site (NQ) on the Tibetan Plateau) and low altitude (Longmen site (LM) in South China) stations using Ka-band millimeter cloud radar, K-band micro rain radar, and Parsivel disdrometer. The manuscript is concise and the results are interesting. However, authors need to consider below mentioned points before accepting the manuscript.
- Authors used too many acronyms, which make difficulty in remember while reading the manuscript. Authors are recommended to remove the acronyms like, SP used for “stratiform precipitation”, PD used for “Parsivel disdrometer”.
For the ease of reading, how about calling the Nagqu site “high altitude site” rather than “NQ”, and Longmen site as “low altitude site” rather than “LM”.
Moreover, authors are suggested to provide all the acronyms used in the manuscript with their description in an appendix table.
- Authors can call K-band micro-rain radar as “MRR” rather than “K-MRR” (as many researchers used the same acronym). Similarly, Ka-band millimeter-wave cloud radar as “cloud radar” rather than “Ka-MMCR”. Parsivel disdrometer as “disdrometer” instead of mentioning it as “PD”. Use “rainfall rate/rain rate” for “Rs”.
- Line 48-51: The definition of BB is incomplete. Authors are suggested to provide detailed description.
- Line 59, 63, 65, 68, 77,79, 84, 87, 100, 103: Please mentioned the reference number for the cited references. Similarly in the rest of the manuscript.
- At line 26, radar equivalent reflectivity is denoted with “ZeS” and at line 141-142 with “Ze”. Authors are suggested to use consistent notation.
- Line 138-145: Authors need to mention the temporal resolution of cloud radar.
- Line 155: Does the MRR provide the difference between Di and N(Di) [ Di-N(Di)]? Please check and modify it.
- In some places for the measured radar reflectivity authors used “Zem” and in other places as “Ze”, use the consistent notation for a given physical parameter.
- Line 230: Authors can provide brief explanation about the consistency test?
Comments for author File: Comments.pdf
Author Response
Response to Reviewer 2 Comments
Dear reviewers,
Thank you very much for your careful reading and constructive comments on our manuscript, which are all valuable and very helpful for revising and improving our manuscript. We have made every effort to revise the manuscript according to your comments and suggestions. Please find below our point-to-point responses in red font, following the review comments, and the corresponding revisions in the manuscript using the "Track Changes" function. Note that the line number described in the following means the line order in the revised manuscript.
We appreciate your kind work.
Best regards,
Jingshu He, Jiafeng Zheng, Zhengmao Zeng, Yuzhang Che*, Min Zheng, Jianjie Li
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Reviewer’s recommendation: In this manuscript, author tried to study the statistical characteristics of bright band center, top, and bottom heights, corresponding radar parameters, and microphysical properties of summer season stratiform precipitation over high altitude (Nagqu site (NQ) on the Tibetan Plateau) and low altitude (Longmen site (LM) in South China) stations using Ka-band millimeter cloud radar, K-band micro rain radar, and Parsivel disdrometer. The manuscript is concise and the results are interesting. However, authors need to consider below mentioned points before accepting the manuscript.
Major revisions
Point 1: Authors used too many acronyms, which make difficulty in remember while reading the manuscript. Authors are recommended to remove the acronyms like, SP used for “stratiform precipitation”, PD used for “Parsivel disdrometer”.
For the ease of reading, how about calling the Nagqu site “high altitude site” rather than “NQ”, and Longmen site as “low altitude site” rather than “LM”.
Moreover, authors are suggested to provide all the acronyms used in the manuscript with their description in an appendix table.
Response 1: Thanks for your valuable advice. As suggested, in the revised version, we use “stratiform precipitation” and “Parsivel disdrometer” instead of SP and PD in the original manuscript. Besides, “NQ” and “LM” in the original manuscript have been replaced with“high altitude site” and “low altitude site”, respectively. In addition, we have added an appendix (Table A1) in lines 736-737 in the revised manuscript, to described the mainly used acronyms.
Point 2: Authors can call K-band micro-rain radar as “MRR” rather than “K-MRR” (as many researchers used the same acronym). Similarly, Ka-band millimeter-wave cloud radar as “cloud radar” rather than “Ka-MMCR”. Parsivel disdrometer as “disdrometer” instead of mentioning it as “PD”. Use “rainfall rate/rain rate” for “Rs”.
Response 2: Thank you very much for the suggestions. As suggested, we call “Ka-band millimeter-wave cloud radar” as “CR”, “K-band micro-rain radar” as “MRR”, and “Parsivel disdrometer” as “disdrometer” in the revised manuscript. Also, the “rain rate” has been changed to “Rs”.
Point 3: Line 48-51: The definition of BB is incomplete. Authors are suggested to provide detailed description.
Response 3: A complete definition of BB is given in lines 59-54 in the revised manuscript.
Point 4: Line 59, 63, 65, 68, 77,79, 84, 87, 100, 103: Please mentioned the reference number for the cited references. Similarly in the rest of the manuscript.
Response 4: Thank you for pointing these out. We have added the reference number for all cited references.
Point 5: At line 26, radar equivalent reflectivity is denoted with “s” and at line 141–142 with “”. Authors are suggested to use consistent notation.
Response 5: We have changed the “” to “” in line 30 in the revised manuscript.
Point 6: Line 138-145: Authors need to mention the temporal resolution of cloud radar.
Response 6: Thanks for the suggestion. The temporal resolution of cloud radar is ~9 s. We actually mentioned in lines 163-164, i.e., "It profiles the aloft clouds and precipitation at a height range from 0.12 to 15.3 km every ~9 s".
Point 7: Line 155: Does the MRR provide the difference between Di and N(Di) [Di-N(Di)]? Please check and modify it.
Response 7: Thanks for pointing the mistake out. Our description is not adequate and therefore we have modified it in lines 181-183 in the revised version.
Point 8: In some places for the measured radar reflectivity authors used “Zem” and in other places as “Ze”, use the consistent notation for a given physical parameter.
Response 8: Thank you for pointing out this. In fact, the "the Ka-MMCR-measured Ze" represents the Ze after data processing and quality control, therefore, we have changed the "the Ka-MMCR-measured Ze " to "CR’s Ze " in the revised manuscript. Similarly, we have changed the "the K-MRR-measured Ze " to "MRR’s Ze ".
Point 9: Line 230: Authors can provide brief explanation about the consistency test?
Response 9: As suggested, a brief explanation on the consistency test has been added in lines 274-279.
Finally, it should be mentioned that some figures are replotted, i.e., Figures 1, 3-10, due to adjustments of abbreviations, and all additional citations have been updated in the section of “References”.
Reviewer 3 Report
The conducted research as a whole is quite interesting, and may represent a certain scientific value and relevance, although in general it has been studied quite well by other researchers. There are following remarks:
1) The phrase "Signal attenuation of the Ka-MMCR is non-negligible" on page 4 is doubtful as at 8.5 mm wavelength attenuation may take significant impact on rain measurements depending on rain rate and hydrometeors distribution.
2) The same attenuation problem, albeit to a lesser extent, is inherent in for K-MRR radar, though there is no relative statetment in the text.
3) Fig. 3 b1 to my opinion is unclear. Is the data absense above BB and in proximity of the result of attenuation ?
4) A number of assumptions are made for the selection of the BB layer. Their validity is insufficient. For example section 2.3.2 on p. 7
5) Mean rain rate in table 1 is rather small, which, in our opinion, is more like a particular than a generality of the studied physical process.
6) I don't really understand how many BB cases were included in the analysis in Table 2 and Figure 4-6 and subsequently.
7) Section Discussion could be strengthened by identifying problems. Now this section looks more like a continuation of the Results section.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
As line numbering between the authors response and the reviewed text provided do not correspond, there is a doubt that the uploaded version is not the final one... beyond the fact that this makes checking the corrections very difficult!
Regarding the authors reponses, most have provided the necessary improvements... The authors should be commpanded for their reactivity. This will benefit the final article.
However it is quite regrettable and detrimental that in a few instances only a very superficial response has been offered while more significant development was at hand.
In particular:
Point 6: you could have offered a discussion based on these new references rather than à mere quote
Point 13: The fitting lines are very usefull but the argument should then be based on these different slopes between the two sites, rather than on the falling path.
Also in the items 2 and 3, this lacks a more detailed analysis as those two claims are somewhat contradictory... unles we account also for ice particule density.
Likewise, the altitude argumetn should be considered in light of atltitude above sea level... as the area comlpared are then at about the same height which annihilates the air density argumetn!
Finally, the sentence "Similar Ze may indicate that the radar attenuates is at such a high gate." is not understandable.
Point 32: "high altitude (Longmen)" is than realy high altitude, while (Longmen) does not appera in the revise"d text, casting further doubts on the actual version provided.Point 34: again, BB at about same altitude above sea level, hence at same atmospheric pressure and density, over both sites, isn't it?
Point 35: It is unfortunate that the answer was to suppress the sentence rather than developping the argument.
Point 36: Hard to find where the improvement has been provided.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
