Continental Thunderstorm Ground Enhancement observed at an exceptionally low altitude
- 1Institute of Atmospheric Physics of the Czech Academy of Sciences, Prague, Czechia
- 2Faculty of Mathematics and Physics, Charles University, Prague, Czechia
- 3Nuclear Physics Institute of the Czech Academy of Sciences, Husinec‑Rez, Czechia
- 4Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czechia
- 5Department of ALDIS, OVE Service GmbH, Vienna, Austria
- 6Institute of Experimental Physics, Slovak Academy of Sciences, Kosice, Slovakia
- 1Institute of Atmospheric Physics of the Czech Academy of Sciences, Prague, Czechia
- 2Faculty of Mathematics and Physics, Charles University, Prague, Czechia
- 3Nuclear Physics Institute of the Czech Academy of Sciences, Husinec‑Rez, Czechia
- 4Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czechia
- 5Department of ALDIS, OVE Service GmbH, Vienna, Austria
- 6Institute of Experimental Physics, Slovak Academy of Sciences, Kosice, Slovakia
Abstract. Two long-lasting Thunderstorm Ground Enhancement (TGE) events were registered at the Milešovka meteorological observatory in Czechia (50.55N, 13.93E, altitude 837 m) on 23 April 2018, during linearly organized thunderstorms. Two intervals of increased photon counts were detected by a plastic scintillator, respectively lasting 70 and 25 minutes, and reaching 31 % and 48 % above the background radiation levels. Using numerical simulations, we verified that the observed increases of count rates are consistent with the energy spectrum of previously observed TGEs. We investigated the relevant data from a suite of meteorological instruments, a Ka-band cloud radar, an electric field mill, and a broadband electromagnetic receiver, all placed at the Milešovka observatory, in order to analyze the context in which these unique continental TGEs occurred at an exceptionally low altitude. The onset of the TGEs preceded the onset of precipitation by 10 and 3 minutes, respectively, for the two events. Both this delayed rain arrival and a lower energy threshold of 6.5 MeV for registered particles clearly exclude the detection the decay products of the radon progeny washout during the TGE intervals. At the same time, the European lightning detection network EUCLID detected numerous predominantly negative intracloud lightning discharges at distances closer than 5 km from the particle detector, while the occurrence of cloud-to-ground discharges was suppressed. The cloud radar recorded presence of graupel below the melting level and the composition of hydrometeors suggested good conditions for cloud electrification. The observed variations of the near surface electric field were unusual, with very brief negative electric field excursions reaching -20 kV in a quick succession. At the same time, sub-microsecond unipolar pulses emitted by close corona discharges saturated the broadband magnetic loop antenna. All these measurements indicate that a strong lower positive charge region was present inside the thundercloud. The bottom thundercloud dipole was probably responsible for acceleration of the seed electrons in the air. These seed electrons might originate not only in the secondary cosmic ray particles but could also come from a high concentration of radon in the air collected during the propagation of the convective system above the uranium-rich soils before the thunderstorms overpassed the Milešovka observatory.
Ivana Kolmašová et al.
Status: final response (author comments only)
-
RC1: 'Comment on acp-2022-125', Ashot Chilingarian, 05 Apr 2022
The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-125/acp-2022-125-RC1-supplement.pdf
-
AC1: 'Reply on RC1', Ivana Kolmasova, 21 Apr 2022
We thank Ashot Chilingarian for careful reading of the manuscript and for his helpful comments and suggestions. We responded to all of them and revised the manuscript accordingly. Our responses together with reviewer´s comments are listed in the attached document.
- RC2: 'Reply on AC1', Ashot Chilingarian, 21 Apr 2022
-
AC1: 'Reply on RC1', Ivana Kolmasova, 21 Apr 2022
-
EC1: 'Comment on acp-2022-125', Heini Wernli, 21 Apr 2022
Many thanks to Dr. Chilingarian for the review and to Dr. Kolmašová for already replying to these comments. But please keep in mind that a 2nd review will come in the following days and the authors should wait with revising the manuscript until all reviews are submitted and the open discussion phase has been closed. With best regards, Heini Wernli (co-editor)
-
RC3: 'Comment on acp-2022-125', Martino Marisaldi, 06 May 2022
This is an interesting paper that reports a very detailed characterization of two Thunderstorm Ground Enhancements detected at low altitude in the Czech Republic. In addition to particle measurements, the paper includes meteo, electric field and radar measurements which are carefully detailed and essential to investigate the environment at the origin of these phenomena. I think the paper is very clear and well written, and I enjoyed reading it. I definitely recommend the paper for publication after my comments are addressed.
The main comments regard the estimate of the cloud base, already addressed also by Ashot, and the methodology used for the simulations. I think there are also some missing references. The comments are attached as annotated pdf (I recommend the use of acrobat reader to view it, as for my experience some comments do not show up in other pdf viewers)
-
AC2: 'Reply on RC3', Ivana Kolmasova, 21 May 2022
We thank Martino Marisaldi for careful reading of the manuscript and for his helpful comments and suggestions. We responded to all of them and revised the manuscript accordingly. Our responses together with reviewer´s comments are listed in the attached document.
-
AC2: 'Reply on RC3', Ivana Kolmasova, 21 May 2022
Ivana Kolmašová et al.
Ivana Kolmašová et al.
Viewed
HTML | XML | Total | BibTeX | EndNote | |
---|---|---|---|---|---|
189 | 57 | 13 | 259 | 2 | 3 |
- HTML: 189
- PDF: 57
- XML: 13
- Total: 259
- BibTeX: 2
- EndNote: 3
Viewed (geographical distribution)
Country | # | Views | % |
---|
Total: | 0 |
HTML: | 0 |
PDF: | 0 |
XML: | 0 |
- 1