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Terrestrial Gamma Ray Flashes due to Particle Acceleration in Tropical Storm SystemsTerrestrial gamma ray flashes (TGFs) are submillisecond flashes of energetic radiation that are believed to emanate from intracloud lightning inside thunderstorms. This emission can be detected hundreds of kilometers from the source by space-based observatories such as the Fermi Gamma-ray Space Telescope (Fermi). The location of the TGF-producing storms can be determined using very low frequency (VLF) radio measurements made simultaneously with the Fermi detection, allowing additional insight into the mechanisms which produce these phenomena. In this paper, we report 37 TGFs originating from tropical storm systems for the first time. Previous studies to gain insight into how tropical cyclones formed and how destructive they can be include the investigation of lightning flash rates and their dependence on storm evolution. We find TGFs to emanate from a broad range of distances from the storm centers. In hurricanes and severe tropical cyclones, the TGFs are observed to occur predominately from the outer rainbands. A majority of our sample also show TGFs occurring during the strengthening phase of the encompassing storm system. These results verify that TGF production closely follows when and where lightning predominately occurs in cyclones. The intrinsic characteristics of these TGFs were not found to differ from other TGFs reported in larger samples. We also find that some TGF-producing storm cells in tropical storm systems far removed from land have a low number of WWLLN sferics. Although not unique to tropical cyclones, this TGF/sferic ratio may imply a high efficiency for the lightning in these storms to generate TGFs.
Document ID
20170007755
Acquisition Source
Langley Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Roberts, O. S.
(University Coll. Dublin, Ireland)
Fitzpatrick, G.
(University Coll. Dublin, Ireland)
Priftis, G.
(Alabama Univ. Huntsville, AL, United States)
Bedka, K.
(NASA Langley Research Center Hampton, VA, United States)
Chronis, T.
(Alabama Univ. Huntsville, AL, United States)
Mcbreen, S.
(University Coll. Dublin, Ireland)
Briggs, M.
(Alabama Univ. Huntsville, AL, United States)
Cramer, E.
(Alabama Univ. Huntsville, AL, United States)
Mailyan, B.
(Alabama Univ. Huntsville, AL, United States)
Stanbro, M.
(Alabama Univ. Huntsville, AL, United States)
Date Acquired
August 17, 2017
Publication Date
March 16, 2017
Publication Information
Publication: Journal of Geophysical Research
Volume: 122
Issue: 6
ISSN: 2169-897X
Subject Category
Meteorology And Climatology
Report/Patent Number
NF1676L-25279
Funding Number(s)
WBS: WBS 281945.02.11.02.30
Distribution Limits
Public
Copyright
Other

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