Juno’s microwave sounding of Jupiter’s atmosphere from pole to pole

Juno’s microwave radiometer has revolutionized our understanding of Jupiter’s atmosphere. By utilizing six microwave channels (0.6 GHz ~ 22 GHz), Juno has scanned Jupiter’s atmosphere from pole to pole, providing near-global, three-dimensional coverage. While the primary goal was to measure water abundance beneath the cloud layer, the data have revealed far more, raising new questions. Notably, the radiometer shows that Jupiter’s weather layer is not generally adiabatic, challenging prior assumptions that convection would homogenize entropy. Furthermore, three distinct atmospheric regions on Jupiter have emerged: the tropics, the mid-latitudes, and the polar regions. The tropics exhibit a distinct temperature structure that features a super-adiabatic temperature gradient across the water condensation level. In the mid-latitudes, the ammonia gas has maintained a vertical gradient down to depths of 50 –100 bars despite vigorous convective mixing. Only the regions near Jupiter’s north pole – perhaps near the south pole as well – closely resemble the long-anticipated moist adiabatic state. This presentation will summarize key findings from Juno’s microwave experiment, spanning both the prime and the extended mission, and highlight significant revisions to our understanding of Jupiter’s atmosphere. We will also discuss the implications for future missions to Saturn, Uranus, and Neptune based on Juno’s microwave results.