Longitudinal variation of F region electron density and thermospheric zonal wind caused by atmospheric tides

Abstract

Simultaneous observations of the electron density and the zonal wind obtained by the CHAMP satellite at 400 km are used to study systematic longitudinal variations. The time period selected is August–September 2004 allowing observations at pre‐noon and post‐sunset hours. The equatorial ionization anomaly (EIA) and the zonal delta‐wind (deviation from zonal average) show a persistent and dominant 4‐peaked longitudinal variation. We interpret this structure as caused by the wavenumber‐3 nonmigrating diurnal tide (DE3). The EIA and the zonal delta‐wind exhibit extrema at about the same longitudes. But, while the intensifications of the EIA and the delta‐wind are in phase during the evening hours, they are out of phase in the morning. Possible coupling mechanisms are investigated.

The International Reference Ionosphere 2012 – a model of international collaboration

“…A good example is the recently discovered four maxima structure in the longitudinal variation of F-peak electron density and of ionospheric electron content that was first observed with IMAGE/EUV observations (Immel et al 2006), and then confirmed with data from CHAMP (Lühr et al 2007) and TOPEX (Scherliess et al 2008), and that is thought to be caused by nonmigrating, diurnal atmospheric tides that are driven by tropospheric weather in the tropics. While theoretical models still struggle to include this phenomenon in their modeling framework, inspection of the longitudinal variation of the F-peak density value NmF2 in IRI revealed that IRI already reproduces this phenomenon (McNamara et al 2010).…”

Climatology of the inter-hemispheric field-aligned current system in the equatorial ionosphere as observed by CHAMP

“…For our investigations the tidal signatures at low-to-middle latitudes are important. Unfortunately, all publications on tidal signatures in ionospheric quantities describe equatorial phenomena (e.g., Lühr et al, 2007Lühr et al, , 2008Park et al, 2010;England et al, 2010, and references therein).…”

Neutral Density and Crosswind Determination from Arbitrarily Oriented Multiaxis Accelerometers on Satellites

“…These papers can be classified by their focus on either the equatorial to mid-latitudes 15,[20][21][22][23] or the polar regions. 24,25 An important early paper on wind derivation from accelerometer data is that by Marcos and Forbes 26 who analyzed triaxial accelerometer measurements from the SETA instrument flown on several spacecraft in the early 1980s.…”