Characteristics of ionosphere at equatorial and middle latitude zones during solar maximum

Abstract

In General, the radio wave transmitted from satellites to receiver will be disturbed in the atmosphere layers. Especially, in the ionosphere layer which is influenced by the total electron content (TEC). It disturbs the radio wave propagation. However, the TEC in the ionosphere layer is always unstable that causes the irregularity of particles in layer. One reason of particle disturbance in the ionosphere is the plasma blown from solar storm. In the statistical information, the solar storm would be the maximum in 2012 of solar cycle 24. It would impact to the radio signal transition in the ionosphere layer. This research investigated the characteristics of ionosphere at equatorial and middle latitude zones during solar maximum. The ionosphere variations in 2012 over Thailand where is located in the equatorial zone and the state of Victoria (Australia) where is located in the middle latitude zone are analyzed by using GPS signal data. In assumption, while GPS propagation is disturbed by the ionosphere layer, in the same way, the characteristic of ionosphere layer can be observed by GPS signal as well. The research result shown that the characteristic of the TEC variation was affected by the solar activity. Furthermore, it was appeared that the TEC was increased uniquely in the two periods a year (Feb, Mar and Apr) and (Dec, Jan, and Feb) at both Thailand and Australia. This phenomenon happened during the equinox period and both areas were characterized by this factor in the same pattern. Even different location but solar activity still is the main factor of the variation. In another result stated that the equatorial ionosphere zone had the amount of electron more than that of the middle latitude ionosphere zone, so it means the ionosphere error in the GPS measurement over the equatorial ionosphere zone would be larger than that of over the middle ionosphere zone.