the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Hailstorm Events in the Central Andes of Peru: Insights from Historical Data and Radar Microphysics
Abstract. Hailstorms, while fascinating from a meteorological perspective, pose significant risks to communities, agriculture, and infrastructure. In regions such as the Central Andes of Peru, the characteristics and frequency of these extreme weather events remain largely uncharted. This study fills this gap by investigating the historical frequency and vertical structure of hailstorms in this region. We analyzed historical hailstorm records dating back to 1958 alongside four years of observations (2017–2021) from Parsivel2 disdrometer and a cloud profiler radar MIRA35c. Our findings indicate a trend of decreasing hail frequency (-0.5 events/decade). However, the p-value of 0.07 suggests the need for further investigation, particularly in relation to environmental changes and reporting methods. The results show that hailstorms predominantly occur during the austral summer months, with peak frequency in December, and are most common during the afternoon and early evening hours. The analysis of radar variables such as reflectivity, radial velocity, spectral width, and linear depolarization ratio (LDR) reveals distinct vertical profiles for hail events. Two case studies highlight the diversity in the radar measurements of hailstorms, underscoring the complexity of accurate hail detection. This study suggests the necessity for refining the Parsivel2 algorithm and further understanding its classification of hydrometeors. Additionally, the limitations of conventional radar variables for hail detection are discussed, recommending the use of LDR and Doppler spectrum analysis for future research. Our findings lay the groundwork for the development of more efficient hail detection algorithms and improved understanding of hailstorms in the Central Andes of Peru.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
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- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2023-997', Anonymous Referee #1, 03 Aug 2023
Please find the review in the attached PDF.
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AC1: 'Reply on RC1', Jairo Valdivia, 08 Feb 2024
Dear Reviewer 1,
We sincerely appreciate the time and effort you have dedicated to reviewing our manuscript. Your insightful comments and constructive feedback have been invaluable in guiding the revisions to enhance the quality and clarity of our work. We have carefully considered each of your suggestions and have made comprehensive revisions to address the concerns raised.
Please refer to the PDF for detailed response.
-
AC1: 'Reply on RC1', Jairo Valdivia, 08 Feb 2024
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RC2: 'Comment on egusphere-2023-997', Anonymous Referee #2, 08 Aug 2023
Reviewer #2
Hailstorm Events in the Central Andes of Peru: Insights from Historical Data and Radar Microphysics
by Jairo Michael Valdivia, David Alejandro Guizado, Elver Villalobos-Puma, José Luis Flores-Rojas, Stephany Magaly Callañaupa, and Yamina Fey Silva-VidalGeneral comments:
This study analyzed hail reports as well as disdrometer and upward pointing radar measurements of hail events at one station in the central Andes. The text, including structure, title, and abstract, and the Figures are of good quality. In my opinion, given my specific comments 2-4, the results lack representativeness and are not very impactful. However, some of the results are perhaps worth publishing and given the wealth of different analyses, including recent topics such as polarimetric radar identification, I could see the study having some relevance for the community. Some points should be clarified before publication.Specific comments:
- l. 97 a map with elevation and the station location would be very helpful I think
- l. 97 Hail is typically infrequent on high mountain regions and more frequent in foothills (see Allen 2017 for Rocky mountains in US and Punge 2017 for the European Alps). I'm missing some justification for why this location was investigated. Is hail an often observed threat there (this doesn't seem to be the case from the hail sizes that you observed, <14mm)? If not, I think it should be made even clearer (in intro and summary especially) that the observations are only representative for the high mountain range, not other regions of Peru (probably not even the whole mantaro river valley which you mention in the intro, give its complex terrain).
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l. 97-103 Are there any other observatories such as this one in Peru which you could add to the analysis? This would increase the robustness of the results.
I'd also personally be very interested in the spatial distribution as our satellite-based detections show some strong activity in Peru, but more in the foothills to the East. Perhaps you can share your experience on this. - section 2 in general: Do you have events of Graupel in this region? How did you make sure events were correctly classified as hail? Was there a minimum size? Later you comment on the observed sizes (line 340), which are almost exclusively small, so I'd wager some of the cases were in fact Graupel. Graupel is also not considered in the Disdrometer (probably because it is indistinguishable from small hail for there), which leads me to suspect that many of the "Hailstorms" in section 3.2 are Graupel.
I think this is very important because Graupel can never become large, while hail can. If most of your events are Graupel, then calling this study an analysis of hail events is very misleading. This should at least be made very clear already in the intro and methods, not late in line 340. - l. 297 (also l. 385) I'm not a microphysics person but in the reference below, high LDR aloft is attributed to the alignment of ice chips in the electric fields (Melnikov, et al. 2019).
Perhaps in general, you could compare your results more to those of other studies (I'm sure the one I found is not the only one using polarimetric radar signatures to classify hail)
- l. 315-319 The radar only sees a vertical section at one point, not the whole 3D cloud, while hail growth happens in 3D trajectories and the stones are advected relative to the updraft (even several km outside the main updraft in some cases), see e.g. Kunjian et al. 2020. Perhaps some perspective on how you relate your 1D (or 2D segments) of measurements to these 3D processes would be insightful. It wasn't clear to me what you mean by "Intuition"
Technical corrections and suggestions:
- l. 44 add space after "severity"
- l. 47 I suggest adding Allen et al. 2018 as reference in the brackets
- l. 52 remove "Beal" once
- l 60-79 repeating all these points here seems a bit redundant. Consider summarizing them in 2-3 sentences or picking the ones most relevant for your study (such as the microphysical aspects)
- l 80-81 "In the Andes" is repeated 3 times here
- l. 101 The text seems broken here, do you mean "...sorrounding the observatory."?
- l. 106-107 I don't understand this sentence. Weren't the reports localized before 2016 as well?
- l. 107-110 I recommend starting this sentence with "However, instruments ..."
- sections 2.1 and 2.2 A lot of this technical information seems irrelevant for the study. I recommend sticking to what is important for hail accuracy and just include a reference for further reading
- Fig. 3 and elsewhere: I'm assuming the times are in local time not UTC? Be clear (if I haven't overread it)
- section 3.3: Just a question, do you think the LDR relationship typically observed in horizontal pointing radar (higher LDR for hail) is better or worse here because you use a verticall pointing radar, which sees falling raindrops from the bottom?
- l.334 "Friedrich" twice
- paragraph starting at l. 328 Good discussion of weaknesses!
- l. 405-413 Just my opinion, but his high self-appraisal seems a bit unprofessional. This is an interesting "pioneering study" yes, but I recommend being a bit more humble about the impact in a scientific publication, if it is not ground breaking.
References:
Kumjian, M. R., and K. Lombardo, 2020: A Hail Growth Trajectory Model for Exploring the Environmental Controls on Hail Size: Model Physics and Idealized Tests. J. Atmos. Sci., 77, 2765–2791, https://doi.org/10.1175/JAS-D-20-0016.1
Melnikov, V., D. S. Zrnić, M. E. Weber, A. O. Fierro, and D. R. MacGorman, 2019: Electrified Cloud Areas Observed in the SHV and LDR Radar Modes. J. Atmos. Oceanic Technol., 36, 151–159, https://doi.org/10.1175/JTECH-D-18-0022.1.
Citation: https://doi.org/10.5194/egusphere-2023-997-RC2 -
AC2: 'Reply on RC2', Jairo Valdivia, 08 Feb 2024
Dear Reviewer 2,
We sincerely appreciate the time and effort you have dedicated to reviewing our manuscript. Your insightful comments and constructive feedback have been invaluable in guiding the revisions to enhance the quality and clarity of our work. We have carefully considered each of your suggestions and have made comprehensive revisions to address the concerns raised.
Please refer to the PDF more detailed response.
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2023-997', Anonymous Referee #1, 03 Aug 2023
Please find the review in the attached PDF.
-
AC1: 'Reply on RC1', Jairo Valdivia, 08 Feb 2024
Dear Reviewer 1,
We sincerely appreciate the time and effort you have dedicated to reviewing our manuscript. Your insightful comments and constructive feedback have been invaluable in guiding the revisions to enhance the quality and clarity of our work. We have carefully considered each of your suggestions and have made comprehensive revisions to address the concerns raised.
Please refer to the PDF for detailed response.
-
AC1: 'Reply on RC1', Jairo Valdivia, 08 Feb 2024
-
RC2: 'Comment on egusphere-2023-997', Anonymous Referee #2, 08 Aug 2023
Reviewer #2
Hailstorm Events in the Central Andes of Peru: Insights from Historical Data and Radar Microphysics
by Jairo Michael Valdivia, David Alejandro Guizado, Elver Villalobos-Puma, José Luis Flores-Rojas, Stephany Magaly Callañaupa, and Yamina Fey Silva-VidalGeneral comments:
This study analyzed hail reports as well as disdrometer and upward pointing radar measurements of hail events at one station in the central Andes. The text, including structure, title, and abstract, and the Figures are of good quality. In my opinion, given my specific comments 2-4, the results lack representativeness and are not very impactful. However, some of the results are perhaps worth publishing and given the wealth of different analyses, including recent topics such as polarimetric radar identification, I could see the study having some relevance for the community. Some points should be clarified before publication.Specific comments:
- l. 97 a map with elevation and the station location would be very helpful I think
- l. 97 Hail is typically infrequent on high mountain regions and more frequent in foothills (see Allen 2017 for Rocky mountains in US and Punge 2017 for the European Alps). I'm missing some justification for why this location was investigated. Is hail an often observed threat there (this doesn't seem to be the case from the hail sizes that you observed, <14mm)? If not, I think it should be made even clearer (in intro and summary especially) that the observations are only representative for the high mountain range, not other regions of Peru (probably not even the whole mantaro river valley which you mention in the intro, give its complex terrain).
-
l. 97-103 Are there any other observatories such as this one in Peru which you could add to the analysis? This would increase the robustness of the results.
I'd also personally be very interested in the spatial distribution as our satellite-based detections show some strong activity in Peru, but more in the foothills to the East. Perhaps you can share your experience on this. - section 2 in general: Do you have events of Graupel in this region? How did you make sure events were correctly classified as hail? Was there a minimum size? Later you comment on the observed sizes (line 340), which are almost exclusively small, so I'd wager some of the cases were in fact Graupel. Graupel is also not considered in the Disdrometer (probably because it is indistinguishable from small hail for there), which leads me to suspect that many of the "Hailstorms" in section 3.2 are Graupel.
I think this is very important because Graupel can never become large, while hail can. If most of your events are Graupel, then calling this study an analysis of hail events is very misleading. This should at least be made very clear already in the intro and methods, not late in line 340. - l. 297 (also l. 385) I'm not a microphysics person but in the reference below, high LDR aloft is attributed to the alignment of ice chips in the electric fields (Melnikov, et al. 2019).
Perhaps in general, you could compare your results more to those of other studies (I'm sure the one I found is not the only one using polarimetric radar signatures to classify hail)
- l. 315-319 The radar only sees a vertical section at one point, not the whole 3D cloud, while hail growth happens in 3D trajectories and the stones are advected relative to the updraft (even several km outside the main updraft in some cases), see e.g. Kunjian et al. 2020. Perhaps some perspective on how you relate your 1D (or 2D segments) of measurements to these 3D processes would be insightful. It wasn't clear to me what you mean by "Intuition"
Technical corrections and suggestions:
- l. 44 add space after "severity"
- l. 47 I suggest adding Allen et al. 2018 as reference in the brackets
- l. 52 remove "Beal" once
- l 60-79 repeating all these points here seems a bit redundant. Consider summarizing them in 2-3 sentences or picking the ones most relevant for your study (such as the microphysical aspects)
- l 80-81 "In the Andes" is repeated 3 times here
- l. 101 The text seems broken here, do you mean "...sorrounding the observatory."?
- l. 106-107 I don't understand this sentence. Weren't the reports localized before 2016 as well?
- l. 107-110 I recommend starting this sentence with "However, instruments ..."
- sections 2.1 and 2.2 A lot of this technical information seems irrelevant for the study. I recommend sticking to what is important for hail accuracy and just include a reference for further reading
- Fig. 3 and elsewhere: I'm assuming the times are in local time not UTC? Be clear (if I haven't overread it)
- section 3.3: Just a question, do you think the LDR relationship typically observed in horizontal pointing radar (higher LDR for hail) is better or worse here because you use a verticall pointing radar, which sees falling raindrops from the bottom?
- l.334 "Friedrich" twice
- paragraph starting at l. 328 Good discussion of weaknesses!
- l. 405-413 Just my opinion, but his high self-appraisal seems a bit unprofessional. This is an interesting "pioneering study" yes, but I recommend being a bit more humble about the impact in a scientific publication, if it is not ground breaking.
References:
Kumjian, M. R., and K. Lombardo, 2020: A Hail Growth Trajectory Model for Exploring the Environmental Controls on Hail Size: Model Physics and Idealized Tests. J. Atmos. Sci., 77, 2765–2791, https://doi.org/10.1175/JAS-D-20-0016.1
Melnikov, V., D. S. Zrnić, M. E. Weber, A. O. Fierro, and D. R. MacGorman, 2019: Electrified Cloud Areas Observed in the SHV and LDR Radar Modes. J. Atmos. Oceanic Technol., 36, 151–159, https://doi.org/10.1175/JTECH-D-18-0022.1.
Citation: https://doi.org/10.5194/egusphere-2023-997-RC2 -
AC2: 'Reply on RC2', Jairo Valdivia, 08 Feb 2024
Dear Reviewer 2,
We sincerely appreciate the time and effort you have dedicated to reviewing our manuscript. Your insightful comments and constructive feedback have been invaluable in guiding the revisions to enhance the quality and clarity of our work. We have carefully considered each of your suggestions and have made comprehensive revisions to address the concerns raised.
Please refer to the PDF more detailed response.
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Journal article(s) based on this preprint
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Jairo Michael Valdivia
David Alejandro Guizado
Elver Villalobos-Puma
José Luis Flores-Rojas
Stephany Magaly Callañaupa
Yamina Fey Silva-Vidal
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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