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Dynasonde approach to ionospheric radio sounding capitalizes on high precision of physical parameters and rich statistics of recognized echoes phase-based methods can provide. As has been recently demonstrated, the Dynasonde profiles of the electron density and of the horizontal gradients, complemented with profiles of the Doppler speed, carry comprehensive quantitative information about Atmospheric Gravity Waves, a ubiquitous feature of the space weather that has become an important objective of atmospheric modeling. Being combined into a time series, and without additional processing, the profiles allow visualization of the time fronts of the Traveling Ionospheric Disturbances (TIDs). They also provide high-resolution input data for calculating the complete set of parameters (both vertical and horizontal) of TID activity in the upper atmosphere between the base of the E layer and the maximum of the F layer. Application of the Lomb-Scargle periodogram technique to the tilt data provides unique insight into the dynamics of spectral composition of the TIDs. A similar technique applied to longer time series allows determining characteristics of thermospheric tides. Single sounding sessions allow observations of ionospheric manifestations of acoustic waves produced by ground-based sources. All the mentioned products of the Dynasonde data analysis require a common, standard ionogram mode of radar operation. Therefore, information about standard parameters of the ionospheric E, F regions, possibility to obtain vector velocities characterizing movement of plasma contours, and quantitative parameters of the km-scale irregularity spectrum are not lost and contribute into comprehensive description of wave activity in the thermosphere-ionosphere system.
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This content will become publicly available on January 1, 2026
Tracking traveling ionospheric disturbances through Doppler-shifted AM radio transmissions
Abstract. Six specialized radio receivers were developed to measure the Doppler shift of amplitude modulation (AM) broadcast radio carrier signals due to ionospheric effects. Five were deployed approximately in a circle at a one-hop distance from an 810 kHz clear-channel AM transmitter in Schenectady, New York, and the sixth was located close to the transmitter, providing a reference recording. Clear-channel AM signals from New York City and Connecticut were also received. The experiment confirmed detection of traveling ionospheric disturbances (TIDs) and measurement of their horizontal phase velocities through monitoring variations in the Doppler shift of reflected AM signals imparted by vertical motions of the ionosphere. Comparison of 12 events with simultaneous global navigation satellite system (GNSS)-based TID measurements showed generally good agreement between the two techniques slightly more than half the time and substantial differences slightly less than half the time, with differences attributable to differing sensitivities of the techniques to wave altitude and characteristics within a complex wave environment. Detected TIDs had mostly southward phase velocities, and in four cases they were associated with auroral disturbances that could plausibly be their sources. A purely automated software technique for event detection and phase velocity measurement was developed and applied to 1 year of data, revealing that AM Doppler sounding is much more effective when using transmitter signals in the upper part of the AM band (above 1 MHz) and demonstrating that the AM Doppler technique has promise to scale to large numbers of receivers covering continent-wide spatial scales.
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- PAR ID:
- 10612139
- Publisher / Repository:
- Copernicus Publications
- Date Published:
- Journal Name:
- Atmospheric Measurement Techniques
- Volume:
- 18
- Issue:
- 8
- ISSN:
- 1867-8548
- Page Range / eLocation ID:
- 1909 to 1925
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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