WIND SPEEDS MEASURED IN THE DEEP JOVIAN ATMOSPHERE BY THE GALILEO PROBE ACCELEROMETERS

The atmosphere of Jupiter has a complex circulation which, until recen tly, has been observable only at the cloud tops(1,2); the mechanisms d riving the winds, and the nature of the interior circulation, remained unknown(3). Recent analyses(4-6) of the radio signal from the Galileo probe, obtained during its descent into the jovian atmosphere, have s uggested a vigorous interior circulation below the 4-bar level. Here w e report an independent measurement of the winds below the cloud tops, making use of the data obtained by the two accelerometers on the desc ending probe. We find evidence for two distinct wind regimes, in gener al agreement with the Doppler radio measurements: a region of wind she ar between 1 and 4 bar, where the wind speed increases dramatically wi th depth; and then a region of constant high-velocity winds down to at least the 17-bar level.