Results from the Third RHESSI Catalog of Terrestrial Gamma-ray Flashes
Abstract
We present a new catalog of terrestrial gamma-ray flashes (TGFs) from the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) satellite. The new catalog includes a large set of new events not detected by either the original algorithm (Grefenstette et al. 2009 JGR 114, A02314) or the more sensitive algorithm of Gjesteland et al. 2012 (GRL 39, L05102). In the new algorithm, searches are conducted separately at time scales of 60, 100, and 300 microseconds and 1, 3, 10, and 30 milliseconds (the original catalog searched only at 1 millisecond binning of the counts). We will discuss the differences between TGFs of different duration in terms of geographical distribution, detailed characteristics of radio sferics observed by the Duke University sensors, and rate of matches with sferics detected by the World Wide Lightning Location Network (WWLLN). We will report in depth on the rare events occurring over the continental United States and off its eastern seaboard, where the expected height of the tropopause is generally lower than the expected production height of TGFs detected from orbit. In addition, we will present detailed modeling of the two bright TGF electron-beam events observed by RHESSI, over northern Africa on 2004 January 17 and over the eastern Mediterranean on 2013 January 18. The new algorithm, using its 10 ms and 30 ms time scales, should be sensitive to such events at a much lower brightness, but has not begun to detect such a population as of this writing. We will present any new events of this type that appear at higher sensitivity, and speculate on why they seem to be so difficult to detect.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMAE23A0409S
- Keywords:
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- 3304 ATMOSPHERIC PROCESSES Atmospheric electricity;
- 3324 ATMOSPHERIC PROCESSES Lightning;
- 4301 NATURAL HAZARDS Atmospheric