DTIC ADA108013: Gust Front Recognition Using a Single-Doppler Radar. | |
by Defense Technical Information Center | |
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A dual-Doppler analysis of a squall-line on 3 May 1977 | |
yielded a three-dimensional wind field within what was | |
considered a typical squall line. This wind field was | |
highly divergent near the surface in the area of the | |
downdraft. Directly above this divergent flow, at a | |
height of 3 to 6 km, the flow became highly convergent, | |
with dry air entrainment observed along the backside of | |
the storm. The wind field above 6 km showed only small | |
areas of weak convergence. This lead to the conclusion | |
that the mid-level (3 to 6 km) air was the main source of | |
the downdraft air responsible for the strong surface | |
outflow. Based on the idea that the mid-level convergence | |
is an indication of a strong downdraft, the dual-Doppler | |
wind field was converted to radial wind fields as would | |
be viewed from various angles by a single-Doppler radar. | |
To be able to use this idea in real-time operations, | |
convergence values along each radial were computed | |
relative to the azimuth of the radar and direction of | |
storm motion. To further illustrate the possible use of | |
this convergence signature, single-Doppler data of three | |
thunderstorms known to have produced strong surface winds | |
were examined. In all three cases, a strong convergent | |
boundary was present in the mid-levels of the storm. This | |
research indicated mid-level convergence may be a | |
characteristic of thunderstorms which produce a strong | |
downdraft and subsequently strong outflow. By identifying | |
such a feature in the mid-levels of the storm, the | |
problems of warning on storms located at a distance in | |
excess of 100 km or storms with a gust front out ahead of | |
the precipitation would be eliminated. | |
Date Published: 2017-12-29 14:38:34 | |
Identifier: DTIC_ADA108013 | |
Item Size: 42951804 | |
Language: english | |
Media Type: texts | |
# Topics | |
DTIC Archive; Mader,Michael William; ... | |
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dticarchive | |
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