Dynamics of ionosphere disturbances along the Eastern-Asian meridian from auroral to equatorial latitudes
Abstract
The research results of ionosphere variation in the Eastern-Asian sector observed at the decay and minimum of solar activity (SA) in the period 2004-2007 during geomagnetic disturbances are presented. Data from ionospheric stations located within the latitude-longitude sector (20-70N, 90-160E), oblique-incidence sounding on the radio paths Magadan-Irkutsk and No-rilsk -Irkutsk and results of total electron content (TEC) measurements at the network of GPS ground-based receivers are used to analyze the variations in ionospheric parameters. Data of zenith photometers are applied to investigate the disturbances of atmospheric emissions. Four groups of anomalous ionospheric disturbances observed during the low solar activity are re-vealed: falls of electron density in the evening hour connected with the formation of equatorial wall of MIT, large-scale ionospheric disturbances, wavelike disturbances with the period of two days, and sharp short-term fluctuations in the electron density more intensive at the middle latitudes during the storm main phase. It was also found that often there was no direct con-nection between ionospheric disturbances and geomagnetic activity during moderate magnetic storms in solar minimum. Observed disturbances can be induced by the joint action of a few factors: the increase in electric field of magnetospheric convection, the generation of AGWs in the auroral zone and their propagation southwestward, and the disturbed neutral winds generated by the large-scale storm-induced thermospheric circulation in addition to TADs as-sociated with winds. The reason for occurrence of the wavelike disturbance with the periods from two till seven days can be the planetary atmospheric waves. The numerical model for ionosphere-plasmasphere coupling was used to interpret the certain of observed data. It is ob-tained that use of empirical models of electron precipitation, magnetospheric convection and thermospheric parameters with the correction by the observed data in general provides a good agreement between calculated and measured values of foF2.
- Publication:
-
38th COSPAR Scientific Assembly
- Pub Date:
- 2010
- Bibcode:
- 2010cosp...38..935P