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The quasi-two-day wave studied using the Northern Hemisphere SuperDARN HF radars
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| Zeitschriftentitel: | Annales Geophysicae |
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| Personen und Körperschaften: | , |
| In: | Annales Geophysicae, 25, 2007, 8, S. 1767-1778 |
| Format: | E-Article |
| Sprache: | Englisch |
| veröffentlicht: |
Copernicus GmbH
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| Schlagwörter: |
| Zusammenfassung: | <jats:p>Abstract. 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. </jats:p> |
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| Umfang: | 1767-1778 |
| ISSN: |
1432-0576
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| DOI: | 10.5194/angeo-25-1767-2007 |