DATA_SET_DESCRIPTION |
Data Set Overview
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From [SEIFFETAL1996]:
The Galileo Probe Atmospheric Structure Instrument (ASI) measured
state properties of Jupiter's atmosphere from nanobar pressure
levels to a final pressure of ~24 bars. The depth reached in the
probe's parachute descent, calculated from measured temperatures
and pressures assuming hydrostatic equilibrium, was ~160 km or
0.22% of the radius of Jupiter. Velocities during descent
decreased from ~400 m/s at parachute deployment to 156 m/s in the
first 100 s, to ~48 m/s at the 3-bar level, and to ~30 m/s at
loss of signal.
Temperatures measured in parachute descent had an accuracy of ~1
K and a dispersion on the order of the digital resolution (0.12
K). Comparison with the Orton model indicates that the
atmosphere is close to a dry adiabat over this pressure range.
Water condensation, expected above the 5-bar level if the oxygen
mole fraction is solar (0.0017) and above the 4-bar level for the
low water abundance detected by the neutral mass spectrometer
(~0.2 of the solar abundance value), has major effects on the
temperature variation. Temperatures following the dry adiabat at
these levels confirm the low water abundance and are consistent
with the absence of a detectable water cloud. Deviations from
the adiabat between 1 and 3 bars, which were initially
interpreted as a stable layer in the tenuous cloud above 1.6 bars
and an unstable layer below the cloud, now are believed to
reflect departures from preflight pressure sensor calibrations
resulting from unanticipated variations in the probe's internal
temperature.
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