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.