Kinematics of Jupiter's Atmosphere from 1 to 100 Bars. First Results from the Juno Microwave Radiometer

The latitude-altitude map of ammonia mixing ratio resembles a global Hadley cell, with values of 320-340 ppm extending from 0.8 bars down to 40-60 bars in a plume within 5° of the equator. Condensation occurs in the ammonia cloud, whose base is at 0.7 bars, and falling precipitation evaporates before it reaches 1 or 2 bars. Ammonia bombs—air made denser by high molecular weight and evaporative cooling, balance the difference between the ammonia vapor brought up in the plume and that carried down at higher latitudes. The eddy momentum flux measured before Juno is consistent with this picture because it shows horizontal divergence and implied upwelling within the equatorial plume. We argue that all the internal heat and vertical exchange of ammonia, at least out to ±40° latitude, is occurring within 5° of the equator.