The height dependence of wave‐normal depression and disturbance amplitude in TID's

Morgan, M. Granger; Ballard, K. A.

doi:10.1029/ja083ia12p05741

Cited by 11 publications

(2 citation statements)

References 13 publications

(14 reference statements)

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“…However, as mentioned above, the sensitivity of GNSS TEC measurements to small electron density fluctuations caused by the passage of TIDs may present a concern, since the major contribution to the TEC is from the topside of the ionosphere. It is known that TID amplitudes maximize near or below the background electron density maximum hmF2 (e.g., Morgan & Ballard, 1978). Therefore, we wanted to verify the results obtained with the GNSS technique by comparing them to independent measurements, that is, HF observations.…”

Section: Resultsmentioning

confidence: 99%

Occurrence and Characteristics of Traveling Ionospheric Disturbances in the Antarctic Peninsula Region

et al. 2022

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A statistical picture of the occurrence and characteristics of Traveling Ionospheric Disturbances (TIDs) over the Antarctic Peninsula is established using Global Navigation Satellite System Total Electron Content and High Frequency sounding observations. The measured parameters of the majority of the disturbances allow classifying them as medium scale TIDs (MSTIDs). Overall, the observed climatology of ionospheric disturbances in the Antarctic Peninsula region varies significantly with the season and makes it possible to differentiate two major types of the disturbances: winter daytime and summer nighttime, based on their occurrence periods and characteristics. During the Antarctic summer period, the disturbances are present mainly during the nighttime and morning hours, when the background plasma density is at maximum (due to Weddell Sea Anomaly). These disturbances predominantly propagate northwestward and their occurrence probability is well correlated with the sporadic E layer observations, suggesting that these are electrified MSTIDs. During the winter, the TID events are almost exclusively observed during the daytime. The propagation direction of the disturbances during the daytime shows a strong correlation with the background neutral wind direction in the thermosphere. A possible mechanism for this effect is wind filtering of the Atmospheric Gravity Waves originating in the troposphere, which indicates that their source is in the lower atmosphere. The periods of the TIDs also significantly differ between the seasons. Wintertime TIDs have noticeably shorter periods (10–50 min) than those observed during other parts of the year (30–140 min), which also likely reflects the fact that the two types of TIDs are generated by different physical mechanisms.

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Section: Resultsmentioning

confidence: 99%

Occurrence and Characteristics of Traveling Ionospheric Disturbances in the Antarctic Peninsula Region

et al. 2022

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“…Ray tracing does account for the refraction which can be determined even for a more physical TID modulation of the background ionosphere than that given in equation . For example, an increasing TID amplitude with height [e.g., Morgan and Ballard , ] can be used or even a tilted TID wave front as suggested by the density contour plot in Figure . The mirror model also fails for near‐vertical incidence when Spitze reflection in the ionosphere [ Poeverlein, ] significantly changes the takeoff and arrival angles from those predicted by a free‐space mirror reflection.…”

Section: Summary and Discussionmentioning

confidence: 99%

Comparing TID simulations using 3‐D ray tracing and mirror reflection

et al. 2016

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Measuring the time variations of Doppler frequencies and angles of arrival (AoA) of ionospherically reflected HF waves has been proposed as a means of detecting the occurrence of traveling ionospheric disturbances (TIDs). Simulations are made using ray tracing through the International Reference Ionosphere (IRI) electron density model in an effort to reproduce measured signatures. The TID is represented by a wavelike perturbation of the 3-D electron density traveling horizontally in the ionosphere with an amplitude that varies sinusoidally with time. By judiciously selecting the TID parameters the ray tracing simulation reproduces the observed Doppler frequencies and AoAs. Ray tracing in a 3-D realistic ionosphere is, however, excessively time consuming considering the involved homing procedures. It is shown that a carefully selected reflecting corrugated mirror can reproduce the time variations of the AoA and Doppler frequency. The results from the ray tracing through the IRI model ionosphere and the mirror model reflections are compared to assess the applicability of the mirror-reflection model.

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The influence of large-scale TIDs on the bearings of geographically spaced HF transmissions

Tedd

Strangeways

Jones

1984

Journal of Atmospheric and Terrestrial Physics

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The height dependence of wave‐normal depression and disturbance amplitude in TID's

Cited by 11 publications

References 13 publications

Occurrence and Characteristics of Traveling Ionospheric Disturbances in the Antarctic Peninsula Region

Occurrence and Characteristics of Traveling Ionospheric Disturbances in the Antarctic Peninsula Region

Comparing TID simulations using 3‐D ray tracing and mirror reflection

The influence of large-scale TIDs on the bearings of geographically spaced HF transmissions

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