نتایج جستجو برای: lightning

تعداد نتایج: 6387  

2005
Thomas L. Murray Richard P. Hoblitt Christina A. Neal

The Alaska Volcano Observatory's lightning detection system detected and located 171 lightning strokes during the August 18, 1992, eruption of the Crater Peak vent of Mount Spurr volcano in Alaska. The strokes, predominantly intracloud, were detected during a 70-minute interval that began more than an hour into the eruption. All detected strokes were of positive polarity. The spatial distributi...

2014
Swati Sharma Shoba Krishnan Ajay Khandare

Lightning discharge emits RF energy over a wide range of frequencies. During cloud to ground lightning, when high currents occur in previously ionized channels, the most powerful emissions occur in the Very Low Frequency range. VLF (very low frequency) refers to radio frequencies spectrum range of 3 kHz to 30 kHz. Detection of lightning makes it possible to avoid various harmful effects occurri...

Journal: :Journal of forensic and legal medicine 2007
O P Murty

This is a case report of an environmental accident due to lightning where one school boy sustained current, blast, and flame effects of it. A bolt of lightning directly struck the pole of a football ground and the scatter struck the child. In addition to burn injuries, he showed an exit wound of lightning in left foot. The exit wound of lightning current is a very rare finding. The body of vict...

2004
J. R. Dwyer H. K. Rassoul M. Al-Dayeh L. Caraway A. Chrest M. A. Uman V. A. Rakov K. J. Rambo D. M. Jordan J. Jerauld C. Smyth

[1] We report measurements of the x-ray emission from rocket-triggered lightning, made during the summer of 2003, using four instruments placed between 15 and 40 m from the lightning channels. X-rays were measured 0–80 ms just prior to and at the beginning of 73% of the 26 return strokes observed. The emission was composed of multiple, very brief bursts of x-rays in the 30–250 keV range, with e...

Journal: :Academic emergency medicine : official journal of the Society for Academic Emergency Medicine 2002
Mary Ann Cooper

The four classic electrical mechanisms of lightning injury cannot account for all injuries. A fifth mechanism, injury by a weak upward streamer that does not become part of a completed lightning channel, has long been postulated in the engineering literature by lightning researchers. This paper reports a case of death where injury from a weak upward streamer is strongly suspected following fore...

2004
Marcos André da Frota

A lightning stepped leader model is developed. To predict the stepped leader is important to protect installations at ground against lightning. The numerical technique TLM (Transmission-line matrix) is applied.

2004
Ulyana A. Dyudina Anthony D. Del Genio Andrew P. Ingersoll Carolyn C. Porco Robert A. West Ashwin R. Vasavada John M. Barbara

Night side images of Jupiter taken by the Cassini Imaging Science Subsystem (ISS) camera with the Hα filter reveal four lightning clusters; two of them are repeated observations of the same storm. All of these flashes are associated with storm clouds seen a few hours earlier on the day side of Jupiter. Some of the clouds associated with lightning do not extend to the upper troposphere. The repe...

1997
SCOTT C. SHERIDAN JOHN F. GRIFFITHS RICHARD E. ORVILLE

This study examines the relationship between cloud-to-ground (CG) lightning and surface precipitation using observations from six regions (each on the order of 10 000 km2), April through October (1989–93), in the southcentral United States. The relationship is evaluated using two different methods. First, regression equations are fit to the data, initially for only the CG lightning flash densit...

2009
Marek Loboda Hans D. Betz Piotr Baranski Jan Wiszniowski Zdzislaw Dziewit

Lightning detection in Poland is performed by means of a PERUN (Safir 3000) system operated by the Institute of Meteorology and Water Management. Poland is also partly covered by a VLF/LF lightning detection system (CLDN, Central Lightning Detection Network). Both sources of lightning data have their limitations resulting from detection technique, limited number of sensors and geographical conf...

2010
TIMOTHY J. LANG STEVEN A. RUTLEDGE

A framework for the statistical analysis of large radar and lightning datasets is described and implemented in order to analyze two research questions in atmospheric electricity: storms dominated by positive cloud-toground (1CG) lightning and estimating the probability of lightning in convection. The framework—a collection of computer programs running in series—is fully modular, allowing the an...

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