Lightningposition in storm may circle strongest updrafts
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Lightning position in storm
may circle strongest updrafts
may circle strongest updrafts
New finding could help in predicting hail, tornadoes
One of a series of stories covering the quadrennial International Conference on Atmospheric Electricity, June 7-11, 1999, in Guntersville, Ala.
"This can be a monitor of severe storm intensity, another tool to monitor when storms might produce tornadoes or hail," said James Dye, a researcher at the National Center for Atmospheric Research in Boulder, Colorado. Dye spoke this week at the International Conference on Atmospheric Electricity.
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But storms still conceal a number of
surprises in many elaborations and variations on that simple
description. Dye said that scientists now are learning that the
most energetic storms are prolific sources of intracloud lightning.
Intracloud lightning, though obscured by the clouds, mayÂ provide
another tool forÂ monitoring severe storms.
Dye's findings come from the Stratospheric-Tropospheric Experiment: Radiation, Aerosols and Ozone (STERAO) Deep Convection experiment in northeast Colorado in June and July 1996. He used data from a French radio interferometer that collected five hours of uninterrupted observations of the locations of lightning within two major electrical storms, and from Doppler radar that shows wind direction and speed within a storm. Combining the two data sets showed where lightning was relative to updrafts and downdrafts.
Left, Above:The main reflector for a Doppler radar, one of the principal tools for peering inside severe storms. (NSSL/NOAA)
"It seems that lightning channels themselves are not in the most intense updrafts," Dye explained, "but in the weaker updrafts and downdrafts." This would seem to go against expectation. But while the lightning avoided the updraft cores, it became more frequent around the cores as the storm grew stronger.
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Dye says no one knows sure why, but the answer probably lies in the microphysics of ice and hail formation, the separation of charges as these bodies grow and move past each other, and how they are transported inside the storms by vertical and horizontal winds.
Voltage (June 18, 1999) Scientists discuss biology, safety,
and statistics of lightning strikes.|
News shorts from Atmospheric Electricity Conference (June 16, 1999) Poster papers on hurricanes and tornadoes summarized.
Soaking in atmospheric electricity (June 15, 1999) 'Fair weather' measurements important to understanding thunderstorms.
Lightning position in storm may circle strongest updrafts (June 11, 1999) New finding could help in predicting hail, tornadoes
Lightning follows the Sun (June 10, 1999) Space imaging team discovers unexpected preferences
Spirits of another sort (June 10, 1999) Thunderstorms generate elusive and mysterious sprites.
Getting a solid view of lightning (June 9, 1999): New Mexico team develops system to depict lightning in three dimensions.
Learning how to diagnose bad flying weather (June 8, 1999): Scientists discuss what they know about lightning's effects on spacecraft and aircraft.
Three bolts from the blue (June 8, 1999): Fundamental questions about atmospheric electricity posed at conference this week.
Lightning Leaders Converge in Alabama (May 24, 1999): Preview of the 11th International Conference on Atmospheric Electricity.
What Comes Out of the Top of a Thunderstorm? (May 26, 1999): Gamma-rays (sometimes).
Lightning research at NASA/Marshall and the Global Hydrology and Climate Center.
An exciting addition to this new suite of research tools would be a satellite-borne Lightning Mapping Sensor, under study at the Global Hydrology and Climate Center, that would observe the Earth continually from geostationary orbit.
"This would provide much more information in terms of intracloud strikes," he said. "It could be an additional forecasting and nowcasting tool" for meteorologists watching severe storms.
Dye cautioned that his and other results are not conclusive yet, but "they're highly suggestive and promising, but we have more work to do."
45th Weather Squadron at Patrick AFB,
lightning reference page.
National Severe Storms Laboratory, Norman, OK
Numerical Modeling at NSSL
The New Mexico Tech 3D Lightning Mapping System
Lightning Detection and Ranging project at Kennedy Space Center.
National Severe Storms Laboratory Photo Library, where we got a lot of the neat pictures in these stories.
More Space Science Headlines - NASA research on the web
NASA's Earth Science Enterprise Information on Earth Science missions, etc.
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