Atmospheric Effects and Precursors of Rainfall over the Swiss Plateau
Round 1
Reviewer 1 Report
Review of "Atmospheric effects and precursors of rainfall over the Swiss Plateau" by Wenyue Wang and Klemens Hocke.
The study focuses on assessing the impact of various environmental parameters on rainfall onset. The study is designed to investigate the impact of environmental parameters during, before, and after rainfall events with a 10-years temporal span covering 1199 rainfall events. The study is well designed and well-documented, and the results are explained in detail. I recommend accepting the manuscript after minor revision.
- The current study investigated the potential of 8 atmospheric parameters on the nowcasting of rainfall. Based on the discussion provided in the introduction section, previous studies have not performed a detailed investigation and this is the main contribution of the current study. I was wondering what will be the significance and contribution of the current study to existing literature? Please add a few lines about the significance of this study in the introduction section.
- Please move the study area before the derivation section. Please add further details like topographical and climatological information to the study area because these also influence the onset of rainfall.
- The results are well-documented and appropriate discussion has been provided. Please add a similar discussion to Figures 2b and 2c to demonstrate the variation of IWV and rain rate with the variation in temperature and IR.
- The first two paragraphs of the discussion section seem results and most of the section can be moved to the results section. The results are barely discussed in the discussion section and compared with previous studies. Please revise the discussions section on the bases of How the results varies from previous studies? The discussion section can be included in this regard and uncertainty sources may also be included.
Author Response
Thank you very much for your good suggestions. There is no doubt that your suggestions play a vital role in improving the quality of this article.
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
General comments
This manuscript focuses on the analysis of precipitation precursors based on surface meteorological data and parameter estimates via a grounded microwave radiometer and an IR sensor at ground. The dataset represents a specific location with a long-term measurement. The manuscript needs adjustments in methodology and more detail in the analysis to be published.
There are three major problems with the study:
- The method used by the authors to define the occurrence of rain was an ILW threshold estimated by MWR. Such threshold may be associated with the presence of raindrops in the cloud and not necessarily with rainfall (see reference 51 and figure 7). Therefore, the results may suffer variations associated with false rainfall detection or its missing. In this case I don't see any problems in using the raingauge instead of the ILW. Or a more detailed study to validate this ILW threshold.
- The manuscript could further detail the characteristics of clouds observed from the point of view of cloud microphysics and their relationship with the environment. The analyzes were generalized and most of the hypotheses presented were not investigated, which makes the results less robust than they could be. Example: Lines 278-284, no analysis of the number of frontal events was shown and no case studies focused on the impacts of these systems.
- Also, about precursors, it refers to prediction or early detection. However, no technique or method has been developed to analyze the ability of these parameters to predict rainfall. Which leaves open the usefulness of this information. The authors in their conclusions (lines 360-361) even defined some values that could indicate this, but did not test their use for this purpose.
Minor comments:
Line 169: In a scientific manuscript every number is important, please explain the reason for using 8 hours before and 16 hours after.
Line 181: “rain over Swiss Plateau”, Please specify the location as your results do not represent the entire region.
Line 260: It is quite difficult to analyze 30 minutes in your figures. Also, the entire methodology discussed about an hourly difference in the information.
Line 261-269: It is unclear to me what the purpose of this analysis would be. Please give more details in a new version of the manuscript.
Line 277: is this air density difference significant?
Lines 323-324: It is quite difficult to analyze a diurnal cycle in these figures, it is necessary to improve the visualization.
Figures:
Figure 4: Why -16h if previous figures are using -8h?
Figure 6: unnecessary, it is an well know scheme.
Author Response
Thank you very much for your good suggestions. There is no doubt that your suggestions play a vital role in improving the quality of this article.
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
In this manuscript, the authors presented a historical review of TROWARA observations with more than a thousand rainfall applications, analyzed observed time series temperature, relative humidity, wind speed and air density and compared the time series before and after rainfall onset. The overall manuscript was logically structured, and the results were properly laid out. However, the overall merits of this manuscript remains in question.
First of all, the entire manuscript reads like a technical report. The statistical analysis is too simple to reveal any insights of the data other than the trend, which might be even simply eyeballed without any calculation. The analysis should focus much more than time lag between those variables and rainfall events, but also deep analysis of physical procedure and their direct contribution to rainfall rate change, environmental interaction in different spatial scope. Besides providing additional datasets and their simple correlation with rainfall events.
The authors laid out a lengthy study over years, but I cannot understand the overall purpose of this article, if there is any other than the time lag analysis as mentioned above. For example, for such long time observation, what kind of climatological insight could be obtained, how additional observations could contribute to better forecasting (please provide a clear framework, not simply mention “it can”). In Line 84, the author referred to “The true detection rate is 87.7%, and the false alarm 84 rate is 38.6%. Joint analysis of IWV and other meteorological observations can achieve 85 improvements to current nowcasting systems indicated by Benevides et al.”, but later in the end of article, the authors claimed (probably) the best indicator of their dataset could achieve a detection rate of 60%! It is very confusing why a forecaster would use this observation source if it cannot lead to a better forecasting skill.
A few ideas might be useful for authors for future reference. The observed variables are easy to obtain from a NWP model, the author could run a short lead-time high resolution local simulation, and compare such variables with this observation, which would provide a much deeper context for physical analysis. It is even possible to run a single point data assimilation experiment to further prove the usefulness of the observations.
Last but not the least, figures about study area introduction are too simple, missing geographic information, which makes reader not familiar with the Bern local area very difficult to understand its climatological and environmental context.
In summary, the manuscript presented a too simple experiment report that does not warrant a publication. I suggest the Editorial Office return this submission to the authors.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
This is an interesting study into developing precursors for rain on the Swiss Plateau. The theory is well presents, and the English is to a good standard. I do not have any major concerns, but do have a couple of questions
1) Have the results been tested to a statistical significance?
2) Could a multivariate analysis better capture the links between the variables?
3) You make the comment about the wind increasing, but this known as the gust front, the displacement of the air as rain is falling and moving towards the observer. Is this not what you are seeing in the wind increase?
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 5 Report
Overall, the article looks okay, the data are presented in various forms and are well described.
I would like the authors to do a more serious analysis.
The correlation found by the authors does not work in all cases, it turns out the article is not quite finished.
In multi-year studies, especially those focused on prediction, the analysis is usually based on empirical models, and machine learning tools are involved.
So this article, although it looks okay, gives the impression of being incomplete.
It is not quite clear why the authors give part 2 with the formulas used to calculate measurable quantities, since they further write that these quantities are measured by the instrument, or do they recalculate from microwave probe data?
Also the authors constantly write about "composite values", if averaging is meant, it is necessary to specify what kind (arithmetic mean, geometric mean).
All comments, questions and suggestions are presented in the attached PDF file.
Comments for author File: Comments.pdf
Author Response
Thank you very much for your good suggestions. There is no doubt that your suggestions play a vital role in improving the quality of this article.
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Thanks to the authors for the answers. The presentation of results has been improved. However, I believe that the issues associated with rain detection still need better accuracy. Please see my observations on the responses given by the authors.
Response 1) Unfortunately, data limitations exist and this is a problem we all have to deal with. To analyze these characteristics, a device that could help would be a radar (vertical pointing or scanning), apparently not available in this study. However, I maintain my earlier concern about the inaccuracy of defining the occurrence of rain. In my opinion this is an important factor.
Response 2) Sorry, unfortunately, I have to partially disagree with the answer. When exposing a hypothesis, some details need to be clarified. I know this can generate new ideas for other studies, but it needs proof how difficult that would be. In this case, a case study could clarify some of the hypotheses presented. And regarding cloud microphysics issues, data from other studies or locations can be used, if the characteristics of those locations are similar. As said by the authors, there are other places with data available that the authors want to use in the future. I'm not saying the authors need to do a robust analysis, again, a case study can clarify some points.
Response 3) Unfortunately, this answer did not clarify whether or not these values can be used to predict rain.
Responses 4-11) Thank you!
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
