Observation based precipitation life cycle analysis of heavy rainfall events in the southeastern Alpine forelands

Haas, Stephanie J.; Kvas, Andreas; Fuchsberger, Jürgen

doi:https://doi.org/10.5194/wcd-6-949-2025

Articles | Volume 6, issue 3

https://doi.org/10.5194/wcd-6-949-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/wcd-6-949-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 6, issue 3

Research article

|

19 Sep 2025

Research article |

| 19 Sep 2025

Observation based precipitation life cycle analysis of heavy rainfall events in the southeastern Alpine forelands

Stephanie J. Haas, Andreas Kvas, and Jürgen Fuchsberger

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Final revised paper (published on 19 Sep 2025)
Preprint (discussion started on 07 May 2025)

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2025-1819', Anonymous Referee #1, 08 May 2025

The brief article of Haas et al. analyses 94 heavy precipitation events in southeastern Alpine forelands. The authors well describe their datasets and methods. The results of their study are reasonable and interesting showing a clear average behavior of the atmospheric parameters before, during and after convective rainfall events. This research area is of high interest for progress in nowcasting of extreme weather events. Thus, I recommend a publication of this study after a minor revision.

Major comments:
1) The Introduction should provide a short overview of related studies, e.g., Cimini et al. 2015: Forecast indices from a ground-based microwave radiometer for operational meteorology , Atmospheric Measurement Techniques , DOI: 10.5194/amt-8-315-2015
2) line 101: a more detailed description or a reference for derivation of CAPE would be interesting.
3) Discussion: it might be interesting if you could discuss the potential of near realtime WEGN3D data for nowcasting of precipitation events

Minor comments:
line 24 sentence is not complete. I think it should be:

These short and highly localized (convective) events which strongly influence ....
Or divide this long sentence into two sentences.

line 94 missing end of the sentence (roughly ????
line 192 in how far are the IWV measurements biased by water films on the antenna (or do you just take GNSS IWV and not radiometer IWV?)
line 242 might be "strong rise" better than "stark rise" ?

Citation: https://doi.org/10.5194/egusphere-2025-1819-RC1
- AC1:
  'Reply on RC1', Stephanie Haas, 15 May 2025
  We thank the reviewer for the thorough assessment, comments, and constructive feedback.
  
  In response to your major comments:
  Thank you for suggesting adding a short description of related studies to the introduction. We added such a paragraph at the end of the introduction:
  
  Finding precursors of rainfall and forecast indices in observation data has been the focus of numerous previous studies. While Cimini et al. (2015) used microwave radiometer profiler data to calculate multiple forecast indices, Wang and Hocke (2022) relied on data from a dual-channel microwave radiometer to investigate local precursors of rainfall events. Data from the Global Positioning System (GPS) and weather station data have been used for the same purpose (Sapucci et al., 2019; Wang et al., 2024). In this study, we leverage the different instruments available in the WEGN3D Open-Air Lab to investigate local HPE precursors in an unprecedented holistic way.
  
  In our study, CAPE is calculated from radiometer-derived T and RH profiles by using the MetPy python package. To clarify this also in the manuscript, we added this information:
  
  All parameters are directly available in the WEGN3D dataset except for the CAPE index, which we calculate from air pressure profiles, and radiometer-derived T and RH profiles using the MetPy Python package (May et al. 2022, version 1.6.3, https://unidata.github.io/MetPy/latest/index.html).
  
  [May, R. M., Goebbert, K. H., Thielen, J. E., Leeman, J. R., Camron, M. D., Bruick, Z., Bruning, E. C., Manser, R. P., Arms, S. C., & Marsh, P. T. (2022). MetPy: A Meteorological Python Library for Data Analysis and Visualization. Bulletin of the American Meteorological Society, 103(10), E2273-E2284. https://doi.org/10.1175/BAMS-D-21-0125.1]
  
  To discuss the potential of near realtime WEGN3D data for nowcasting of precipitation events, we added the following sentences to the discussion:
  
  The WEGN3D’s capability to adequately capture very characteristic features of high-intensity small-scale rainfall events while being solely observation-based (i.e., generated without any models) illustrates the high potential for applications of this dataset in the improvement and verification of weather and climate models. Specifically, the data could be used to develop an experimental nowcasting model for the region. Of particular interest could be the investigation of using atmospheric precursors of (heavy) precipitation in addition to extrapolation-based nowcasting methods (cf. Wang et al., 2024; Bojinski et al., 2023). Given the holistic setup of the instruments, such a model can be adjusted and verified in a very fine-grained manner, potentially serving as a blueprint for improving larger-scale models.
  
  In response to your minor comments:
  Line 24: We see that the sentence was indeed a bit confusing. Thus we changed it according to your suggestions, thank you for bringing that to our attention.
  
  Incomplete sentences: Apparently there was a problem with the file upload, the sentences you refer to are complete in our local version of the manuscript. We are sorry for that and will make sure that the revised manuscript will not have the same issues.
  
  Bias of IWV measurements: As mentioned in the manuscript (Data section and Table 1), we only use IWV data from GNSS measurements for this study. The IWV is therefore not biased by the water films on the radiometer housing.
  
  Line 242: Thank you for that suggestion, we changed “stark rise” to “strong rise”.
  
  Citation: https://doi.org/10.5194/egusphere-2025-1819-AC1
RC2:
'Comment on egusphere-2025-1819', Anonymous Referee #2, 06 Jun 2025

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-1819/egusphere-2025-1819-RC2-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2025-1819-RC2
- AC2: 'Reply on RC2', Stephanie Haas, 07 Jul 2025
  
  Please see the attached file for our answers to reviewer #2
  
  Citation: https://doi.org/10.5194/egusphere-2025-1819-AC2

Peer review completion

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

AR by Stephanie Haas on behalf of the Authors (04 Jul 2025) Author's tracked changes Manuscript

EF by Vitaly Muravyev (08 Jul 2025) Author's response

ED: Referee Nomination & Report Request started (08 Jul 2025) by Heini Wernli

RR by Anonymous Referee #2 (04 Aug 2025)

ED: Publish subject to minor revisions (review by editor) (07 Aug 2025) by Heini Wernli

Dear Stephanie
Thanks for submitting a revised version of your paper. One reviewer looked again at your manuscript and I also skimmed through it. The reviewer is now mainly happy with the revisions, but still has a few interesting points for you to consider and potentially improve. I also have a short list of more formal points or formulations that you can improve, see the list below. Please prepare your final version by considering these comments and again provide a point-by-point response about how you addressed the suggestions.
With best regards,
Heini

----------------
Suggestions from the Editor:

!! my line numbers are from the file with tracked changes !!

L10: The sentence "Beginning with ..." seems to me grammatically wrong, please rephrase.

L13: please specify "we find an increase ...": when? during the 8 h before the event? or do you mean that during events these parameters are increased compared to climatology? please clarify.

abstract: I would find it very interesting if you could mention in the abstract the timing of your 94 events (at what time of the day do they typically occur? and in what months of the year?).

L36 but also in other places: please list references chronologically

L68: "unprecedented holistic way" is maybe a bit exaggerated, maybe chose a more modest formulation.

Eq. 1: this is not good notation, why is hourly precipitation called I_P and 5-min precipitation PA? I would just write that hourly precipitation rates are estimated from 5-min accumulated measurements by multiplying with a factor of 12.

Section 2.2.2: please re-consider your notation. I have never seen AH for absolute humidity (you mean specific humidity in g/kg? or mixing ratio in g/m3?); q or w would be the more common symbols. For all variables, please indicate their unit, and if you use symbols (like T for temperature, then T should be in italics). Abbreviations (RH, IWV, ...) should remain in roman letters.

Figure 6: it is unclear to me what you mean by "regional anomaly" - is this a deviation from the domain mean, or from climatology? And which event are you showing in Fig. 6 (indicate the date)? And what do you mean by "accumulated PA" (is this the total precipitation within 20 minutes)?

Figure 7: for panel c, the caption says it is T2M, but it is likely a T2M anomaly (again, relative to what?)

L317: again, it is important that the reader here understand what you mean by "anomaly" (deviation from climatology? from domain mean? from ...?)

L326: it is good tradition when reporting about observations, to make the point that they are important for improving models (and predictions). But do you have a specific suggestion how your results could help with this? I very much like your observational analysis, but I don't see immediately how a model can be improved given your study, and therefore the final statement sounds a bit overly general. Maybe you would like to emphasise that one could do similar analyses with high-resolution weather prediction models and quantify whether they have the correct time evolution of T2M, CAPE etc. prior to HPEs?

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AR by Stephanie Haas on behalf of the Authors (13 Aug 2025) Author's response Author's tracked changes Manuscript

ED: Publish as is (14 Aug 2025) by Heini Wernli

AR by Stephanie Haas on behalf of the Authors (14 Aug 2025)

Short summary

In southeast Austria, summer thunderstorms often cause severe damage but are very hard to accurately forecast. With data from the WegenerNet 3D Open-Air Laboratory, we study these storms from beginning to end in multiple atmospheric parameters, like temperature, cloud properties, and wind speed. The characteristic features we find in these parameters expand our understanding of intense storms and can improve their prediction.

Observation based precipitation life cycle analysis of heavy rainfall events in the southeastern Alpine forelands

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