The variations of the electron density0f the middle ionosphere during the year cycle
Abstract
The hight changes of the form and the amplitude of the year variations of electron density N are studied at 140-200 km. The calculations by the semiempirical models describing N under dependence from the neutral gas state are used. The models have been worked on the experimental data base, received by ionogram inversion [Shchepkin L.A., Kushnarenko G.P., Freison I.A. and Kuznetsova G.M. //Geomagnetizm and aeronomy (in Russian). 1997. V.37, No5, p.106] and by the rocket experiments [Shchepkin L.A., Kushnarenko G.P., Kuznetsova G.M. //Geomagnetizm and aeronomy (in Russian). 2002.V42.,No3,p.376]. The maximum values of N are in summer and minimum ones are in winter at the height interval 140-170 km. At 190 and 200 km the year variations of N are in opposite phase with the low heights. The amplitude of the discussed variations is the least at 180 km . The discussed effect at 190 and 200 km is more pronounced in the longitudinal sector where the North dip pole is located. This connected with the spatial thermosphere structure as described by MSIS-86 model. The similar variations are given by the IRI2000 model during the year of minimum solar activity (1996). The described peculiarities of height changes of N variations are caused by the changes in neutral gas composition state and of the character of the charged particles neutralization processes . This work is done with financial support of the Russian Foundation for basic Research ( project No. 02-05-64157).
- Publication:
-
35th COSPAR Scientific Assembly
- Pub Date:
- 2004
- Bibcode:
- 2004cosp...35.1236S