Kilometric type III burst enhancements associated with interplanetary shocks

Type III bursts have been observed in the 30–100 kHz range which show localized enhancements in their spectra. The enhancements exhibited by a series of type III bursts extending over a period of several hours show a consistent decrease in frequency. The rate of this decrease is consistent with the movement of an interplanetary shock. The passage of such a shock by the Earth is suggested by the occurrence of sudden commencements at approximately the expected time.