Long term variations in Jupiter's 11 cm radio emission

Five series of observations were made of the polarization of Jupiter's radio emission at a wavelength of 11 cm. This data shows characteristics which have been stable over a period of years as well as some unexplained variations. The observations were made during one complete orbital period of Jupiter and hence were obtained over the full range of value of Dsub(E), the angle between Jupiter's rotational axis and the plane of the sky. Each series of observations consisted of measurements of the total flux, fractional polarization, and the position angle of the linearily polarized component as a function of Jovian longitude. The data from each type of measurement was analysed by fitting a 7 parameter Fourier series. (author)