Details

Autor(en) / Beteiligte

• Norouzi-Sedeh, L.
• Waters, C. L.
• Menk, F. W.

Titel

Survey of ULF wave signatures seen in the Tasman International Geospace Environment Radars data

Ist Teil von

• Journal of geophysical research. Space physics, 2015-02, Vol.120 (2), p.949-963

Ort / Verlag

Washington: Blackwell Publishing Ltd

Erscheinungsjahr

2015

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Ultralow frequency (ULF) plasma waves propagate through the magnetosphere and ionosphere where they can alter the Doppler velocity of HF radar echoes. Data from the two Tasman International Geospace Environment Radars and the fluxgate and induction coil magnetometers located on Macquarie Island (54.5°S, 158.95°E geographic) over 2006–2009 show that ULF wave signatures are common. Using coincident radar and magnetometer data selection criteria, 194 events representing a total of 233.4 h were identified. The majority of ULF signatures seen in the radar data were detected between 06 and 12 UT (15 and 21 LT). Using the Maximum Entropy Method, the spectral content showed favored frequencies of 1.6, 2.1, 2.9, and 3.3 mHz but no obvious variation of frequency with latitude. Most of the observed frequencies were in the range 1–4 mHz. A class of Doppler velocity signatures that appeared as a zigzag shape in the radar range:time plots were identified and may be related to the expected plasmapause latitudes. Regularly spaced, favored frequencies appeared in the ground magnetometer data during the afternoon, night, and morning sectors for those days where ULF wave events were observed in the radar data. Key Points ULF wave signatures are common in midlatitude Doppler radar data ULF event occurrence peaks over 15–21 LT with 2 mHz the most common frequency Favored frequencies of 1.6, 2.1, 2.9, and 3.3 mHz are observed