Longitudinal variation in E- and F-region ionospheric trends
Jarvis, Martin J.. 2009 Longitudinal variation in E- and F-region ionospheric trends. Journal of Atmospheric and Solar-Terrestrial Physics, 71 (13). 1415-1429. 10.1016/j.jastp.2008.05.017Full text not available from this repository.
A novel technique is used to examine northern hemisphere midlatitude longitudinal variations in ionospheric long-term trends. Differences in hour-by-hour monthly median ionospheric parameters between equilatitudinal observatory pairs are analysed for long-term trends, thus eliminating at source the large solar cycle and geomagnetic variability that normally hinders ionospheric trend calculations. The results confirm the finding of Bremer [1998. Trends in the ionsopheric E- and F-regions over Europe. Annales Geophysicae 16, 698-996] that there are longitudinal variations in the F-region altitude trend across Europe, but suggest the influence of a stationary wave-like feature between 3 degrees W and 104 degrees E. Possible causes such as scaling errors, insufficient account of changes in ionisation underlying the F-region, varying gravity wave fluxes, and secular change in the geomagnetic field are ruled out. The data suggest that the longitudinal variation may reflect long-term changes in a large-scale stationary feature induced via non-migrating tides induced by latent heat release in the troposphere. Significant differences in the long-term trend of E-region peak plasma frequency between observatories were also found. These E-region differential trends varied with solar zenith angle reaching over 0.3 MHz per decade between Juliusruh and Moscow at midday in summer. (C) 2008 Elsevier Ltd. All rights reserved.
|Programmes:||BAS Programmes > Polar Science for Planet Earth (2009 - ) > Climate|
|Additional Keywords:||Ionosphere; Trend; Planetary wave; Longitudinal|
|NORA Subject Terms:||Physics
|Date made live:||04 Nov 2010 09:57|
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