Abstract Real heights in the ionospheric F region, as calculated from ionograms, are subject to appreciable uncertainties because of our poor knowledge of the size and shape of the valley region between the E and F layers. Even with good extraordinary ray data we need model values for the valley depth, if we are to obtain the valley width (and hence the heights in the F region) with good accuracy. Theoretical profiles across the E/F valley region have been calculated using the MSIS86 atmospheric model, with full allowance for the effects of different ionising wavelengths and night-time ionisation sources. These profiles are used to determine the valley depth and width at all local times. Midlatitude results are presented as a function of solar zenith angle x∼ for summer and winter conditions at solar minimum and solar maximum. Valley widths are consistently about 20 km at x > 40°, increasing to 40 km at x 90°. Daytime valley depths are greater than expected, giving a mean ratio NV/NE of about 0.7 for zenith angles less than 85°.
Aeronomical calculations of valley size in the ionosphere
Advances in Space Research ; 10 , 8 ; 21-24
01.01.1989
4 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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