Digital Video Captures Images of 'Blue Jet'
Meteorologists have long speculated about the existence of electrical discharges between the tops of thunderclouds and the upper atmosphere. Now a team from Pennsylvania State University in University Park, New Mexico Institute of Mining and Technology in Socorro and Stanford University in Stanford, Calif., has documented such a discharge by digitally recording the propagation of a luminous atmospheric phenomenon called a "blue jet" from the top of a cloud to a distance 70 km into the ionosphere.
The researchers, who published their results in the March 14 issue of Nature, captured the images with a Sony DCR-TRV730 CCD video camera equipped with an ITT Industries Night Vision Night Quest 6010 intensifier. The event, which occurred above a relatively small storm cell 200 km northwest of Arecibo Observatory in Puerto Rico, appeared in 24 of the 33-ms-long video frames and displayed speeds of more than 105 m/s, characteristic of lightning leaders.
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