The Galileo Probe Doppler Wind Experiment: Measurement of the deep zonal winds on Jupiter

During its descent into the upper atmosphere of Jupiter, the Galileo probe transmitted data to the orbiter for 57.5 min. Accurate measurements of the probe radio frequency, driven by an ultrastable oscillator, allowed an accurate time history of the probe motions to be reconstructed. Removal from the probe radio frequency profile of known Doppler contributions, including the orbiter trajectory, the probe descent velocity, and the rotation of Jupiter, left a measurable frequency residual due to Jupiter's zonal winds, and microdynamical motion of the probe from spin, swing under the parachute, atmospheric turbulence, and aerodynamic buffeting. From the assumption of the dominance of the zonal horizontal winds, the frequency residuals were inverted and resulted in the first in situ measurements of the vertical profile of Jupiter's deep zonal winds. A number of error sources with the capability of corrupting the frequency measurements or the interpretation of the frequency residuals were considered using reasonable assumptions and calibrations from prelaunch and in-flight testing. It is found that beneath the cloud tops (about 700 mbar) the winds are prograde and rise rapidly to 170 m/s at 4 bars. Beyond 4 bars to the depth at which the link with the probe was lost, nearly 21 bars, the winds remain constant and strong. Corrections for the high temperatures encountered by the probe have recently been completed and provide no evidence of diminishing or strengthening of the zonal wind profile in the deeper regions explored by the Galileo probe.

[1]  S. Collins,et al.  Jovian winds from Voyager 2. I. Zonal mean circulation. , 1982 .

[2]  A. Barcilon,et al.  A Moist, Hadley Cell Model for Jupiter's Cloud Bands , 1970 .

[3]  J. Pollack,et al.  Retrieval of a wind profile from the Galileo Probe telemetry signal , 1992 .

[4]  P. Gierasch.  Jovian meteorology: Large-scale moist convection , 1976 .

[5]  R. Beebe,et al.  Pre-Voyager velocities, accelerations and shrinkage rates of jovian cloud features , 1979, Nature.

[6]  P. Stone.  An Application of Baroclinic Stability Theory to the Dynamics of the Jovian Atmosphere , 1967 .

[7]  G. Schubert,et al.  Thermal structure of Jupiter's atmosphere near the edge of a 5‐μm hot spot in the north equatorial belt , 1998 .

[8]  A. Ingersoll,et al.  Solar heating and internal heat flow on Jupiter , 1978 .

[9]  J. Holton.  An introduction to dynamic meteorology , 2004 .

[10]  V. M. Linkin,et al.  Overview of VEGA Venus Balloon in Situ Meteorological Measurements , 1986, Science.

[11]  D. Hunten,et al.  Low-latitude thermal structure of Jupiter in the region 0.1-5 bars , 1980 .

[12]  E. J. Reese.  Summary of Jovian latitude and rotation period observations from 1898 to 1970. , 1972 .

[13]  P. Gierasch.  Atmospheric Dynamics on the Outer Planets , 1996, Science.

[14]  A. Ingersoll,et al.  Motion in the interiors and atmospheres of Jupiter and Saturn: scale analysis, anelastic equations, barotropic stability criterion , 1982 .

[15]  S. Limaye.  Erratum - Jupiter - New Estimates of the Mean Zonal Flow at the Cloud Level , 1986 .

[16]  R. Hide.  The giant planets. , 1982 .

[17]  Jan-Peter Muller,et al.  Measurements of wind vectors, eddy momentum transports, and energy conversions in Jupiter's atmosphere from Voyager 1 images , 1980 .

[18]  C. B. Farmer,et al.  Structure and meteorology of the middle atmosphere of Venus: Infrared remote sensing from the Pioneer Orbiter , 1980 .

[19]  B. Conrath,et al.  Albedo, internal heat, and energy balance of Jupiter: Preliminary results of the Voyager Infrared Investigation , 1980 .

[20]  D. Hunten,et al.  Conversion of para and ortho hydrogen in the Jovian planets , 1982 .

[21]  J. L. Mitchell,et al.  Interaction of eddies and mean zonal flow on Jupiter as inferred from Voyager 1 and 2 images , 1981 .

[22]  L. Travis,et al.  Cloud morphology and motions from Pioneer Venus images , 1980 .

[23]  C. Chapman.  Jupiter's Zonal Winds: Variation with Latitude , 1969 .

[24]  P. Gierasch.  Dynamical Consequences of Orthohydrogen-Parahydrogen Disequilibrium on Jupiter and Saturn , 1983, Science.

[25]  L. Lanzerotti,et al.  High-Energy Charged Particles in the Innermost Jovian Magnetosphere , 1996, Science.

[26]  P. Gierasch,et al.  Thermal structure and dynamics of Saturn and Jupiter , 1981, Nature.

[27]  J. Apt,et al.  Structure and circulation of the Venus atmosphere , 1980 .

[28]  P. Gierasch,et al.  Global variation of the para hydrogen fraction in Jupiter's atmosphere and implications for dynamics on the outer planets , 1984 .

[29]  D. W. Allan,et al.  Statistics of atomic frequency standards , 1966 .

[30]  S. Krimigis,et al.  Low‐energy charged particle observations in the 5–20 RJ region of the Jovian magnetosphere , 1981 .

[31]  G. Hunt,et al.  Motions and morphology of clouds in the atmosphere of Jupiter , 1976 .

[32]  Charles C. Counselman,et al.  Zonal and meridional circulation of the lower atmosphere of Venus determined by radio interferometry , 1980 .

[33]  Frank S. Milos,et al.  Structure of the Atmosphere of Jupiter: Galileo Probe Measurements , 1996, Science.

[34]  T. Spilker,et al.  Refraction effects on the Galileo probe telemetry carrier frequency , 1991 .

[35]  B. M. Peek.  The planet Jupiter , 1958 .

[36]  F. Flasar.  Global dynamics and thermal structure of Jupiter's atmosphere , 1986 .

[37]  A. Ingersoll,et al.  Deep winds on Jupiter as measured by the Galileo probe , 1997, Nature.

[38]  P. J. Schinder,et al.  Jupiter's ionosphere: Results from the First Galileo Radio Occultation Experiment , 1997 .

[39]  T. Maxworthy.  The dynamics of a high-speed Jovian jet , 1984 .

[40]  A. Ekonomov,et al.  Preliminary results on the Venus atmosphere from the Venera 8 descent module , 1973 .

[41]  M. Oestreich,et al.  Earth-Based Radio Tracking of the Galileo Probe for Jupiter Wind Estimation , 1997, Science.

[42]  T. Dowling.  Estimate of Jupiter's Deep Zonal-Wind Profile from Shoemaker-Levy 9 Data and Arnol'd's Second Stability Criterion , 1995 .

[43]  A. C. Riddle,et al.  Redefinition of system III longitude , 1976 .

[44]  Wind speeds measured in the deep jovian atmosphere by the Galileo probe accelerometers , 1997, Nature.

[45]  R. Sagdeev,et al.  Determination of Venus Winds by Ground-Based Radio Tracking of the VEGA Balloons , 1986, Science.

[46]  J. Simpson,et al.  Dynamics of the Jovian magnetosphere and energetic particle radiation , 1976 .

[47]  Bradford A. Smith,et al.  The Jupiter System Through the Eyes of Voyager 1 , 1979, Science.

[48]  F. Busse.  A simple model of convection in the Jovian atmosphere , 1976 .

[49]  V. V. Kerzhanovich,et al.  Data on dynamics of the subcloud Venus atmosphere from Venera Spaceprobe measurements , 1972 .

[50]  R. Nazirov,et al.  Differential VLBI measurements of the Venus atmosphere dynamics by balloons: VEGA-Project , 1990 .

[51]  J. Pollack,et al.  Galileo Doppler Measurements of the Deep Zonal Winds at Jupiter , 1996, Science.