Observations of traveling ionospheric disturbances with a satellite-beacon radio interferometer: Seasonal and local time behavior

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/94JA02663· OSTI ID:70524

Jacobson, A R; Carlos, R C; Massey, R S; Wui, Guanghui ^[1]

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1. Los Alamos National Lab., NM (United States)

The authors have operated a very long baseline interferometer array at a northern midlatitude site, illuminated by VHF radio beacons from two geosynchronous satellites, quasi-continuously for over a year. The array can detect and measure the trace velocity of traveling ionosphere disturbances (TIDs) via their signatures in the line-of-sight total electron content (TEC). The system noise level is of the order of 10{sup 13} m{sup {minus}2} in the TEC, so that even very weak perturbations can be studied. They have used the year-long TID detection/velocimetry data set to describe local time and seasonal dependences of the wave parameters. The most striking finding is that the preferred azimuths of TIDs in the data set tend to belong to either of two modes: The first mode, strongest at midday and in the early afternoon, particularly around winter equinox, propagates southward. The second mode, strongest in the evening, especially during summer solstice through autumn equinox, propagates west-northwestward. The two modes are disposed in local time such as to suggest the agency of clockwise rotation of the TID preferred azimuths versus time, as expected by wind filtering in the thermospheric diurnal tide. However, there is a gap between the two modes` azimuth bands. Moreover, the two modes exist in all trace-speed quartiles of the data set TIDs, a finding which is at variance with the hypothesis of wind filtering being the primary explanation of these modes. 28 refs., 13 figs.

• OSTI ID: 70524
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: A2 Vol. 100; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
INTERFEROMETRY
SEASONAL VARIATIONS
TRAVELLING IONOSPHERIC DISTURBANCE
WAVE PROPAGATION