On the mechanism of seasonal and solar cycle NmF2 variations: A quantitative estimate of the main parameters contribution using incoherent scatter radar observations

摘要: [1] Seasonal (winter/summer) and solar cycle NmF2 variations as well summer saturation effect in have been analyzed using Millstone Hill incoherent scatter radar (ISR) daytime observations. A self-consistent approach to the Ne(h) modeling has applied extract from ISR observations a consistent set of main aeronomic parameters estimate their quantitative contribution observed variations. The retrieved are independent uncertainties thermosphere EUV empirical models, this is distinguishing feature present consideration. Different temperatures winter course overlapped on O+ + N2 reaction rate coefficient temperature dependence result different dependences activity: steep practically linear increase with tendency turn up January (contrary international reference ionosphere prediction) slow saturate at high activity July despite increasing irradiation. In flux thermospheric provide approximately equal contributions increase, while small. Both atomic oxygen [O] small F2 layer peak, its compared loss coefficient, β. It shown that under not just reduced O/N2 or but determined by β via γ1 dependence. new mechanism (qualitative) explain December anomaly proposed. based idea areas production spatially separated time required transfer one area other where associates three-body collision. Therefore, 7% O2 dissociation due Sun-Earth distance decrease December–January June–July, an accumulation should take place vicinity solstice resulting 21% which close global effect.