Multifrequency, long wave, vertical sounding of the lower ionosphere
By: B.W. Reinisch, G.S. Sales
Contributors: Sales, Gary S.
Series: Environmental Research Papers -- no. 460; Environmental research papers (Hanscom AFB, Mass.) -- no. 460
Publisher: United States Air Force, Air Force Systems Command, Air Force Cambridge Research Laboratories, Ionospheric Physics Laboratory
Published: 1973
Place of publication: Bedford, Mass
Language: eng
Number of pages: 13
Subjects: Lower ionosphere; Long wave radiation
Description: 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)
Notes: "AFCRL-TR-74-0002."

"Ionospheric Physics Laboratory Project 5631."

20 December 1973."

Cover title.

Includes bibliographical references (p. 13).