The internal structure of Jupiter’s Great Red Spot

Abstract:

Contrasts in thermal emission within and surrounding Jupiter’s Great Red Spot (GRS) were mapped at six frequencies by the Juno Microwave Radiometer (MWR) during its 7^th flyby (PJ7) over Jupiter. Compared to the average thermal emission at the other longitudes, the GRS appears brighter by about 22 K in the 0.6-GHz (50-cm) channel, which senses thermal emission from hundreds of bars in pressure. The brightness-temperature anomaly decreases with increasing altitude and almost vanishes at the 2.6-GHz (11.5-cm) channel, probing approximately the 10-bar pressure level. At levels shallower than 10 bars, the GRS exhibits a brightness-temperature asymmetry in latitude, with thermal emission from the northern part of the GRS being fainter and the southern part being brighter by up to 10 K compared to the average. A novel way of exploring the degenerate space of temperature and opacity is developed by progressively increasing the constraint on the temperature profile. The result suggests that the GRS has an extended upwelling branch in the north between 20^oS ~ 16^oS originating at depths > 100 bars (230 km down from the 1-bar level) and a narrow subsiding branch in the south near 23.5^oS penetrating to about 30 bars. We did not see the bottom of the GRS in our longest wavelength channel, which means that the bottom of the GRS must be deeper than 100 bars.