Relationships between auroras and sporadic-E echoes

During March, 1951, a series of visual auroral observations were made simultaneously with ionospheric soundings at Point Barrow, Alaska. Observations were made every 15 minutes during the dark hours of ten successive clear nights. Some 400 simultaneous observations were made. Auroras were present during about 90 per cent of these observations. Analysis indicates that quiet auroras
45\deg
or more above the horizon, were correlated with certain sporadic-E region echoes. The more intense the aurora, the higher the maximum frequency returned. The closer the auroral form was to the zenith, the shorter the range of the "Es" echoes. Active auroral displays were usually accompanied by a sharp increase in radio wave absorption. Local geomagnetic variations coincident with auroral displays were also examined.