Accession Number : AD0778087

Title :   Multifrequency, Long Wave, Vertical Sounding of the Lower Ionosphere.

Descriptive Note : Environmental research papers,

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : Reinisch,B. W. ; Sales,G. S.

Report Date : 20 DEC 1973

Pagination or Media Count : 14

Abstract : Vertical pulse sounding at 30, 60, 180, and 520 kHz at Quabbin Reservoir, MA, USA, reveals diurnal and seasonal variations in structure, reflectivity, and height of the lower ionosphere. A solid state wideband amplifier feeds 10 kW peak power into a ground-laid six-element antenna. A special digital sampling and integration scheme selects median values of amplitude and phase received at perpendicular loop antennas. Day and nighttime D-region model profiles are fitted to the observed data by matching group height and reflection coefficient. Emphasis is placed on the nighttime residual E-layer observed at 100 km with an electron density, under undisturbed conditions, around 1000/cc. Long and short term variability of this layer is considerable. It is often semi-transparent as indicated by simultaneous E- and F-region echoes, suggesting the presence of a valley above the nighttime E-layer. (Author)

Descriptors :   *Atmospheric sounding, *Ionosphere, Electron density, Radiofrequency

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE