Propagating planetary wave coupling in SABER MLT temperatures and GPS TEC during the 2005/2006 austral summer

摘要

It has long been suggested that the existence of ionospheric oscillations at multiday periodicities can be explained in part, by the penetration of propagating planetary waves into the E region ionospheric dynamo. In this study, global‐scale observations of mesosphere and lower thermosphere (MLT) temperatures from TIMED/SABER and total electron content (TEC) results from GPS derived global ionosphere maps are examined for signs of potential upward planetary wave coupling, around the time of an intense quasi 2 day wave (QTDW) event in the MLT region during 1 December 2005 to 28 February 2006. The periodicity and zonal wave number of westward 3 (W3) and westward 2 (W2) QTDWs are resolved continuously in equatorial ionization anomaly (EIA) latitude TEC values at the same times as corresponding QTDW events in SABER temperatures. Additionally, signatures of an E1 ultrafast Kelvin (UFK) or inertia‐gravity wave with period around 60 h (2.5 d) are also resolved. While the TECs also show signs of geomagnetic activity, the coherence and consistency of the aforementioned disturbances between the MLT and the ionosphere suggest that they cannot be attributed to geomagnetic forcing. We find that such propagating planetary waves can produce transient variability of the EIAs, though the effectiveness and hemispheric symmetry of such coupling also depends on factors other than the maximum planetary wave amplitude in the MLT.