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| Titel |
The quasi-two-day wave studied using the Northern Hemisphere SuperDARN HF radars |
| VerfasserIn |
S. B. Malinga, J. M. Ruohoniemi |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 25, no. 8 ; Nr. 25, no. 8 (2007-08-29), S.1767-1778 |
| Datensatznummer |
250015894
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| Publikation (Nr.) |
 copernicus.org/angeo-25-1767-2007.pdf |
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| Zusammenfassung |
| Data from the Super Dual Radar Network (SuperDARN) radars for 2002 were used
to study the behaviour of the quasi-two-day wave (QTDW) in the Northern
Hemisphere auroral zone. The period of the QTDW is observed to vary in the
range of ~42–56 h, with the most dominant period being ~48 h and
secondary peaks at ~42- and ~52-h. The spectral power shows a
seasonal variation with a peak power (max~70) in summer. The power
shows variations of several days and there is also evidence of changes in
wave strength with longitude. The 42-h and the 48-h components tend to be
strongly correlated in summer. The onset of enhanced wave activity tends to
coincide with the westward acceleration of the zonal mean flow and occurs at
a time of strong southward meridional flow. The most frequent instantaneous
hourly period is in the 40 to 50 h period band, in line with the simultaneous
dominance of the 42-h and the 48-h components. The wave numbers are less
variable and are around −2 to −4 during times of strong wave activity. For a
period of ~48 h, the zonal wave number is about −3 to −4, using a negative
value to indicate westward propagating waves. The 42-h and the 52-h
components cover a wider band in the −4 to 1 range. The wide zonal
wave number spectrum in our results may account for the observed longitudinal
variation in the spectral power of the wave. |
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