NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
observation of gravity waves during the extreme tornado outbreak of 3 april 1974A continuous wave-spectrum high-frequency radiowave Doppler sounder array was used to observe upper-atmospheric disturbances during an extreme tornado outbreak. The observations indicated that gravity waves with two harmonic wave periods were detected at the F-region ionospheric height. Using a group ray path computational technique, the observed gravity waves were traced in order to locate potential sources. The signals were apparently excited 1-3 hours before tornado touchdown. Reverse ray tracing indicated that the wave source was located at the aurora zone with a Kp index of 6 at the time of wave excitation. The summation of the 24-hour Kp index for the day was 36. The results agree with existing theories (Testud, 1970; Titheridge, 1971; Kato, 1976) for the excitation of large-scale traveling ionospheric disturbances associated with geomagnetic activity in the aurora zone.
Document ID
19780067007
Document Type
Reprint (Version printed in journal)
Authors
Hung, R. J.
(Alabama Univ. Huntsville, AL, United States)
Phan, T.
(Alabama, University Huntsville, Ala., United States)
Smith, R. E.
(NASA Marshall Space Flight Center Space Science Laboratory, Huntsville, Ala., United States)
Date Acquired
August 9, 2013
Publication Date
July 1, 1978
Publication Information
Publication: Journal of Atmospheric and Terrestrial Physics
Volume: 40
Subject Category
GEOPHYSICS
Funding Number(s)
CONTRACT_GRANT: NSF ATM-75-15706
CONTRACT_GRANT: NAS8-31171
Distribution Limits
Public
Copyright
Other