A new type of Doppler velocity fluctuations in HF ground scatter from the polar cap

Title: A new type of Doppler velocity fluctuations in HF ground scatter from the polar cap
Creator: Scoular, G.; Ponomarenko, P. V.; St.-Maurice, J. P.
Relation: Geophysical Research Letters Vol. 40, Issue 19, p. 4992-4997
Publisher Link: http://dx.doi.org/10.1002/grl.50960
Publisher: Wiley-Blackwell Publishing
Resource Type: journal article
Date: 2013
Description: We report a new type of variations in Doppler velocity of HF ground scatter echoes from the polar cap at f~10 mHz. Similar fluctuations from lower latitudes are usually associated with large-scale dayside Pc3-4 ULF waves. However, the polar cap oscillations exhibit a puzzling anisotropy in spatial coherence along and across the radar’s line of sight. Furthermore, in contrast to Pc3-4 waves, these fluctuations show no ground magnetic signatures and display a pronounced gap in power/occurence around local noon. We hypothesize that localized, ≤100 km, auroral particle precipitations near the radar site can modulate Doppler shift of the radio waves entering the ionosphere. In the ground scatter returns, due to the geometrical spread of the rays propagating through the ionosphere to the ground, these variations would appear to have a much larger line-of-sight scale.
Subject: ULF waves; SuperDARN; HF radar; Pc3-4; polar cap
Identifier: http://hdl.handle.net/1959.13/1061642
Identifier: uon:16989
Identifier: ISSN:0094-8276
Language: eng
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