Results 161 to 170 of about 451,064 (205)

Frequency estimation of travelling ionospheric disturbances

1996 IEEE International Symposium on Circuits and Systems. Circuits and Systems Connecting the World. ISCAS 96, 2002
The use of adaptive filters in estimating the instantaneous frequency of Doppler shifted signals reflected from the ionosphere is addressed in this paper. With the aid of a software simulator, it has been shown that an adaptive linear predictor is effective in extracting the required Doppler shift.
J.M. O'Keefe, D.A. Campbell, L.W. Cahill
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The effects of travelling ionospheric disturbances on ionograms

Journal of Atmospheric and Terrestrial Physics, 1977
Abstract The numerical synthesis of ionograms by ray-tracing in an analytic two-dimensional ionosphere is simplified by a technique which avoids the usual wastage of ray tracings. The technique is particularly suitable for obtaining ionogram sequences corresponding to a moving ionospheric disturbance.
R.J. Lobb, J.E. Titheridge
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Travelling disturbances in the ionosphere

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 1950
Abstract Methods have been developed for the examination of the horizontal and vertical movements of short-period disturbances in the ionosphere. It has been found that quasi-periodic travelling disturbances with periods of from 10 to 60 min. are of frequent occurrence in the F region by day. They appear as temporary variations in the
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On the Relationship Between Traveling Atmospheric Disturbances and Traveling Ionospheric Disturbances

Journal of Geophysical Research: Space Physics
AbstractAs the typical thermospheric/ionospheric wave, traveling atmospheric disturbances (TADs)/traveling ionospheric disturbances (TIDs) always carry and transfer a large amount of energy and momentum during geomagnetic storms. In this study, we conducted a model simulation to explore the relationship between TADs and TIDs.
Bowei Liu, Jing Liu, Xuanqing Liu, Shuhan Li, Libo Liu   +4 more
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Travelling disturbances associated with ionospheric storms

Journal of Atmospheric and Terrestrial Physics, 1965
Following each of three geomagnetic sudden commencements, ionospheric disturbances (ionospheric storms) are found to propagate from two isolated locations in high-latitude regions of the Earth. These two positions are conjugate points (magnetically), and are in different locations for each magnetic storm.
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Traveling Ionospheric Disturbance Mitigation for OTH Radar

2007 IEEE Radar Conference, 2007
Deflection of HF propagation paths by traveling ionospheric disturbances (TIDs) remains a troubling cause of coordinate registration errors for over-the-horizon (OTH) radar. Bandwidth and coverage limitations in ionospheric soundings preclude the ability to model TID structure in real time in most cases.
L. J. Nickisch, Mark A. Hausman, Sergey Fridman   +2 more
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Evidence of Directional Filtering of Travelling Ionospheric Disturbances

Nature Physical Science, 1972
IT has recently been pointed out1 that the strong thermospheric winds would act as a directional filter. In a windy thermosphere an otherwise penetrating gravity wave may become reflected or asymptotically trapped near the lower thermosphere. Because both reflexion and trapping take place below the ionospheric F2 peak, such waves may not excite ...
K. C. YEH, H. D. WEBB, D. H. COWLING
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GPS radio interferometry of travelling ionospheric disturbances

Journal of Atmospheric and Solar-Terrestrial Physics, 1998
Abstract This paper presents some results investigating the new possibilities of radio interferometry of Travelling Ionospheric Disturbances (TIDs) that are based on exploiting standard measurements of transionospheric radio signal characteristics and coordinate-time measurements using dual-frequency multichannel receivers of the Global Positioning ...
E.L. Afraimovich, K.S. Palamartchouk, N.P. Perevalova   +2 more
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Three-dimensional observations of traveling ionospheric disturbances

Journal of Atmospheric and Terrestrial Physics, 1971
Abstract Twenty-five measurements of vertical and horizontal trace velocities of medium size traveling ionospheric disturbances were made near sunset at Boulder, Colorado from June 1967 through June 1968. The total speeds of the TID's were slightly larger in summer than in winter with a mean value of 143 m/s.
Kenneth Davies, John E. Jones
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Topside Ionospheric Response to Large‐Scale Traveling Ionospheric Disturbances

Journal of Geophysical Research: Space Physics
Abstract Understanding the formation, progression, and global impact of Large Scale (LS) Traveling Ionospheric Disturbances (TIDs) is a long‐standing challenge in global space weather research. At high latitudes, the magnetosphere injects significant energy into the Ionosphere‐Thermosphere (I‐T) system through Joule heating, auroral ...
A. G. Burrell, K. Zawdie, M. Burleigh, M. Dhadly, F. Sassi, A. Coster   +5 more
openaire   +1 more source