Notes on radio fade‐out of August 25, 1936

Abstract

An extensive fade‐out of radio signals in the Western Hemisphere occurred between 18h and 20h GMT, August 25, 1936. R. L. Garrison, Chief of Communications for Pan‐American‐Grace Airways, Inc., reported that communication was disturbed along the entire western coast of South America between these hours. P. D. Boothroyd, operator for the Mackay Radio Telephone and Telegraph Company at Seattle, Washington, sets the time of the fade‐out as from 18h 25m to 19h 20m GMT. Other reports indicate that the fade‐out was experienced from New York to Honolulu. The magnetic and earth‐current records at the Huancayo Magnetic Observatory of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington also exhibited disturbed conditions during the fade‐out according to reports received from O. W. Torreson and W. E. Scott. Reproductions (see Fig. 1) of magnetic record from the Huancayo Observatory and also from that of the Cheltenham Magnetic Observatory of the United States Coast and Geodetic Survey (by courtesy of Director Patton) show departures identical in time with the radio phenomenon. At Huancayo a marked change of some 70 gammas occurred in horizontal intensity, while at Cheltenham a marked change of 6′—equivalent there to about 35 gammas—occurred in declination. There was no marked change in vertical intensity at either station which indicates that the magnetic effects associated with the fade‐out induced currents within the Earth of sufficient magnitude to neutralize the vertical component of the field‐change.

Large gradual solar energetic particle events

“…Having searched in vain for other instances of the simultaneity of solar eruptions and geomagnetic disturbances, many scientists, including Lord Kelvin (see Ellis 1901), abandoned the notion that an erupting sunspot may have a causal relationship with co-temporal geomagnetic activity. Some 80 years later, following the discovery that bright eruptions in the solar chromosphere cause simultaneous radio fade-outs and distinct terrestrial effects by Fleming (1936), Bartels (1937) provided a complete description of what is now universally known as the 1859 Carrington event.…”

Solar flare effects on the geomagnetic elements during normal and counter electrojet periods

“…Dellinger (1935) reported simultaneous occurrence of short wave fade out (SWF) during the crochet time. The concomitant phenomena of solar flare, crochet and short wave fade out soon received much interest of many scientists (Fleming, 1936;Richardson, 1936;Torreson et al, 1936). The effects of solar flares on the geomagnetic field records, vertical incidence pulsed ionosphere sounding records and earth current records all at an equatorial station Huancayo were first described by McNish (1937).…”

Solar Flare Effect on the Geomagnetic Field

“…Fleming (1936) calld special attention to a remarkable example of the simultaneity of a solar chromospheric eruption, an extensive fade-out of HF radio signals and a conspicuous change in the geomagnetic field, which all took place almost simultaneously on August 25, 1936. As illustrated in Fig.…”