Sprites observed outside the U.S.

Don Savage
Headquarters, Washington, DC              June 7, 1995
(Phone:  202/358-1547)

Kathy Berry 
Geophysical Institute, University of Alaska, Fairbanks
(Phone:  907/474-7798)

RELEASE:  95-84


       NASA researchers have captured on videotape the 
first conclusive evidence that the mysterious flashes of 
red light called sprites -- which extend up to 55 miles 
above electrical thunderstorms -- are not limited to the 
United States.

       The research team from the Geophysical Institute of 
the University of Alaska, Fairbanks, recorded the unusual 
flashes above thunderstorms near the equator in South 
America last February and March.  Previously, they had seen 
the recently discovered sprites above storms only in the 
U.S., leading some scientists to question whether or not 
they occur in other parts of the world.

       Geophysical Institute researchers Davis Sentman, 
Gene Wescott and Daniel Osborne used special low-light-
level cameras aboard a Westwind-2 jet aircraft to record 
the brief flashes.  The flights, part of a NASA-sponsored 
investigation into the phenomenon, were coordinated with 
the Peruvian Air Force.  The researchers recently completed 
an analysis of the footage gained during their flights.

       In form and in visual appearance, the sprites over 
South America look similar to flashes recorded by the team 
over storms in the central U.S. last summer.  About 500 
sprites were recorded last June and July, many on color 
video for the first time.  None of the sprite groups seen 
this winter over South America were as large or as intense 
in color as some of the larger groups recorded over the U.S.

       Less intense thunderstorms may have contributed to 
the smaller number and desultory appearance of the sprites 
in South America.  In the southwestern-central U.S., the 
storms form along a quickly moving frontal system, but the 
convective storms in South America are nearly stationary; 
they tend to grow in place, develop slowly into large 
systems like boiling water, then dissipate.

       Some scientists had speculated that sprites might 
not exist over equatorial regions because thunderstorms 
there frequently do not get larger than about 100 miles, 
which some thought was the minimum size needed to produce a sprite.

       Pilots and others also have reported seeing blue or 
greenish columns propagate upward at great speed from the 
top of thunderstorms.  Wescott and Sentman were the first 
to report the video capture and the characteristics of 
"blue jets" from 1994 flights over the U.S.  No blue jets 
were seen over South America.  

       Sprites can be seen from the ground after dark with 
the unaided eye under the right conditions.  To encourage 
pilots and others to report sprite sightings around the 
world, Sentman is establishing a Sprite Watcher's Homepage 
on the World Wide Web.  The homepage will give brief 
information about sprites, the conditions needed to view 
sprites from the ground or air, and simple directions to 
follow when recording a sighting.  All public sightings 
will be incorporated into a scientific database, and then 
displayed on a global map for Web users.

       Researchers from government laboratories, universities,
and Federal agencies will continue to investigate sprites and other
phenomena associated with thunderstorms this summer during two main
campaign efforts.  A team from the Geophysical Institute will observe
storms from Colorado mountain tops to support optical observations 
of sprites made from the Yucca Ridge Field State east of Fort Collins,
CO.  Research into what causes sprites will be made using radio
frequencies, radar, and other measuring techniques at additional
sites across the eastern half of the U.S.

       More than two dozen scientists from across the 
country will participate in a second major campaign, which 
will focus on thunderstorms around northern Florida.  
Facilities and capabilities at NASA's Kennedy Space Center 
will be used in the study.


EDITOR'S NOTE:  Individuals interested in participating 
in the sprite research or receiving further information via 
the internet can access the 
Sprite Watchers Homepage.

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