Thesis (M.Sc.)--Chulalongkorn University, 2013

Magnetic clouds (MCs) and various phenomena hit the ionosphere every day. Total electron contents (TEC) in the ionosphere influence on trans-ionospheric radio propagation. The interaction between MCs, phenomena, and TEC was not clearly known. Two aims of this research are to (1) study TEC variation resulting from MC and other phenomena by using percent deviation of TEC, (2) MC,parameters of the other phenomena, and TEC variation coefficients. TEC under 6 magnetic clouds (MCs), 5 interplanetary shocks (ISs), 2 interaction regions (IRs), 2 sheathes, 10 high speed streams (HSSs), and 5 coronal streams (CSs) derived from GPS stations in north and south America for estimated deviation of TEC. Therefore the computer program was constructed to answer this question. The motion of MC, sheathes, and ISs made TEC increase to be the equatorial ionospheric anomaly (EIA) but dTEC% resulting from MC and various phenomena can’t estimate in this study. Parameters of MC and various phenomena, and TEC can be fitted by the linear regression. Each latitude has its equation, andin the same latitude of different events, will have the different equations. Coefficients of variation of TEC under these motions do not depend on geodetic latitude.