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Estimation of neutral wind velocity in the ionospheric heights by HF-Doppler techniqueThree net stations located about 100 kilometers apart were set up around the station of the standard frequency and time signals (JJY) in central Japan and measurements of atmospheric gravity waves in the ionospheric heights (F-region, 200 to 400 km) were made by means of the HF-Doppler technique during the period of February 1983 to December 1983. The frequencies of the signals received are 5.0, 8.0 and 10.0 MHz, but only the 8.0 MHz signals are used for the present study, because no ambiguities due to the interference among other stations such as BPM, BSF, etc. exist by the use of 8.0 MHz. Two main results concerning the horizontal phase velocity of the atmospheric gravity waves with periods of 40 to 70 min may be summarized as follows: (1) the value of the phase velocity ranges from 50 m/s to 300 m/s; (2) the direction of the gravity wave propagation shows a definite seasonal variation. The prevailing direction of the gravity waves in winter is from north to south, which is consistent with the results obtained from other investigations. On the other hand, the two directions, from northeast to southwest and from southeast to northeast, dominate in summer.
Document ID
19860018313
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Kitamura, T.
(Kyushu Univ. Fukuoka, Japan)
Takefu, M.
(Kyushu Univ. Fukuoka, Japan)
Hiroshige, N.
(Kyushu Univ. Fukuoka, Japan)
Date Acquired
August 12, 2013
Publication Date
December 1, 1985
Publication Information
Publication: International Council of Scientific Unions Handbook for MAP, Vol. 18
Subject Category
Geophysics
Accession Number
86N27785
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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