Seasonal Variations in the Activity Factor of Jupiter’s Hemispheres Restored Their Periodicity

Abstract

Abstract—It has been concluded that, in the powerful magnetosphere of Jupiter, the subsolar point, which changes its position over the orbital period by an angle of approximately 26°, causes seasonal variations in the physical characteristics of the atmosphere. The significant eccentricity of the planetary orbit leads to the fact that the influx of energy to the atmosphere in the northern hemisphere is 21% greater, because the planet is at perihelion at the time close to the summer solstice for the northern hemisphere. This causes the asymmetry in the meridional distribution of the reflective properties of the visible cloud layer. The analysis of the observational data for 1960–2019 shows that the ratio A_J = B_N/B_S adequately describes the changes in the atmospheric processes on Jupiter, showing quasi-periodic variations in the reflective characteristics of the northern and southern temperate and tropical regions over the period of the orbital motion around the Sun (11.87 years). The change in Jupiter’s integral brightness in the V visual band indicates a more pronounced effect of the 22.1-year Hale magnetic cycle of solar activity. The results of the visible-light observations in 1960–1995 and 2012–2019 showed a synchronous delay of several years as a response to a 21% change in the irradiation of different hemispheres as the planet moves in orbit. In 1995–2012, a disagreement was observed between the dependence A_J, the solar activity index S_n, and the mode of the solar irradiation of Jupiter due to its orbital motion. After 2012, the course of the time dependence of these three parameters again became consistent, restoring the periodicity of the variations in the photometric characteristics of the northern and southern hemispheres of Jupiter.