Transpolar Propagation of Long Radio Waves.
In order to predict radio-wave propagation behavior in abnormally ionized atmospheres, it is helpful to understand phenomena observed during natural distrubances, for which considerable amounts of data exist. Accordingly, this report examines the propagation of very-low-frequency and extremely-low-frequency waves during normal periods and during polar cap absorption events. One of the main goals of the study is to ascertain the effects of the Greenland ice pack on the transpolar propagation of long radio waves. This is essential if propagation data are to be related correctly to the state of the ionosphere. Also, the study is intended to assist in the interpretation of high-latitude propagation experiments sponsored by the Defense Atomic Support Agency. The calculations correctly predict that much larger signal losses and distortion will be suffered on paths that cross Greenland than over sea or conducting ground. 40 pp. Ref. (Author)