Publications

The climatological model of the equatorial electrojet, EEJM-1, derived from Ørsted, CHAMP and SAC-C satellite measurements [Alken and Maus, 2007] provides the opportunity to investigate the longitudinal variation of the current strength in detail. Special emphasis is put in this paper on the effect of non-migrating tides. We have found that the influence of the diurnal eastward propagating mode with wavenumber 3, DE3, is particularly strong. In polar orbiting satellite observations the DE3 tidal signal appears as a four-peaked longitudinal structure. The amplitude of the DE3 signature in the EEJ peaks during equinox seasons, but it is also strong around the June solstice. When looking at the relative modulation depth of the EEJ intensity the DE3 accounts for about 25% during the months April through September. It is thus the dominant cause for longitudinal variations. During December solstice months the influence of DE3 is negligible. A secondary three-peaked longitudinal pattern emerges during solstice seasons when the DE3 influence is removed. From the data available it is, however, not clear whether this pattern is related to any tidal drivers.

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Lühr, H.; Rother, M.; Häusler, K.; Alken, P.; Maus, S. (2008): The effect of non-migrating tides on the equatorial electrojet. 12th International Symposium on Equatorial Aeronomy (ISEA12) (Heraklion, Crete, Greece 2008).