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may circle strongest updrafts |
"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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Above: Time-lapse photography captures multiple cloud-to-ground lightning strokes During a night thunderstorm over Norman, Oklahoma, March, 1978. (C. Clark, NOAA) |
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, may provide
another tool for monitoring severe storms. 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. |
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. |
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. More Space Science Headlines - NASA research on the web NASA's Earth Science Enterprise Information on Earth Science missions, etc. |
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