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DOI	10.5194/acp-22-7959-2022
	Continental thunderstorm ground enhancement observed at an exceptionally low altitude
	Kolmasova, Ivana; Santolik, Ondrej; Slegl, Jakub; Popova, Jana; Sokol, Zbynek; Zacharov, Petr; Ploc, Ondrej; Diendorfer, Gerhard; Langer, Ronald; Lan, Radek; Strharsky, Igor
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	7959
结束页码	7973
卷号	22 期号:12 页码:15
英文摘要	Two long-lasting thunderstorm ground enhancement (TGE) events were registered at the Milesovka meteorological observatory in Czechia (50.55 degrees N, 13.93 degrees E; 837 m altitude) 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 min and reaching 31 % and 48 % above the background radiation levels. Using numerical simulations, we verified that the observed increases in 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 Milegovka observatory, in order to analyse 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 min, respectively, for the two events. Both this delayed rain arrival and an 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 in 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 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 Milesovka observatory.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000813038400001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273713
作者单位	Czech Academy of Sciences; Institute of Atmospheric Physics of the Czech Academy of Sciences; Charles University Prague; Czech Academy of Sciences; Nuclear Physics Institute of the Czech Academy of Sciences; Czech Technical University Prague; Slovak Academy of Sciences
推荐引用方式 GB/T 7714	Kolmasova, Ivana,Santolik, Ondrej,Slegl, Jakub,et al. Continental thunderstorm ground enhancement observed at an exceptionally low altitude[J],2022,22(12):15.
APA	Kolmasova, Ivana.,Santolik, Ondrej.,Slegl, Jakub.,Popova, Jana.,Sokol, Zbynek.,...&Strharsky, Igor.(2022).Continental thunderstorm ground enhancement observed at an exceptionally low altitude.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(12),15.
MLA	Kolmasova, Ivana,et al."Continental thunderstorm ground enhancement observed at an exceptionally low altitude".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.12(2022):15.