Solar radio emissions and geophysical disturbances during July 1959

Abstract

This paper briefly summarizes spectral observations of solar radio bursts taken at Fort Davis, Texas, and Sydney, Australia, during July 1959, and relates these observations to the geophysical disturbances at that time. The period is notable because of the occurrence of several great solar flares and their subsequent terrestrial effects. Some of these events have been described elsewhere [Winckler, 1960]. Spectral observations of solar radio emission were made at Fort Davis for 98 per cent of the possible observing time during July 1959. The daily observing period covered the hours 1230 until 0145 UT the following Greenwich day, i.e., from sunrise to sunset. The equipment at Fort Davis comprised five sweep-frequency receivers, which together gave complete coverage of the range 25–580 Mc/s. At 100 Me/s, bursts of intensities 1, 2, and 3 correspond to signal intensities of 5–40, 40–200, and >200 watts m−2 cps−1×10−22 respectively. Similar spectral observations were also made at Sydney, Australia, over the frequency range 25–210 Mc/s. As the Australian results are of interest in the study of the solar-terrestrial events during July 1959, their published observations are included in Table 1. No observations were made at Sydney on July 4, 11, 18, or 25. Their observing periods generally were from about 2300 until about 0600 UT the following Greenwich day. The Australian intensity figures are not the same as those given for Fort Davis, but they are of the same order.