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Ionospheric slab thickness in middle and low latitudes
Author(s) -
Davies K.,
Liu X. M.
Publication year - 1991
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/91rs00831
Subject(s) - noon , ionosphere , atmospheric sciences , flux (metallurgy) , equinox , slab , geomagnetic latitude , latitude , earth's magnetic field , daytime , electron density , total electron content , middle latitudes , physics , geology , electron , geophysics , tec , geodesy , materials science , magnetic field , quantum mechanics , metallurgy
The equivalent slab thickness of the ionosphere at 15 stations in middle and low latitudes was studied to determine its dependence on solar cycle and location. The data were grouped by season. The following are the major conclusions. There appears to be little or no geographical, or geomagnetic, dependence. The slab thickness varies approximately linearly with the 12‐month smoothed values of the 10.7‐cm solar radio flux. In middle latitudes the winter midnight thickness is essentially independent of the flux, whereas in summer and equinox the midnight thickness increases with increase of solar flux. The noon thickness increases with increase of solar flux in all seasons. The zero‐order Fourier coefficients for the diurnal curves at all 15 stations were expressed as linear functions of the 10.7‐cm flux. The higher harmonic coefficients showed no appreciable dependence on solar flux. The pronounced predawn increase in slab thickness is caused by low values of the maximum electron density, not by increase of total electron content.