Gravity anomalies on Venus

Sjogren, W. L.; Phillips, R. J.; Birkeland, Peter W.; Wimberly, R. N.

doi:10.1029/ja085ia13p08295

Cited by 57 publications

(17 citation statements)

References 13 publications

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“…That map agrees well with the radial gravity map prepared by Bowin [1983a, Figure 7] between latitudes 60°N and 45°S, and both differ similarly from line-ofsight gravity maps at spacecraft altitude [e.g., Sjogren et al, 1980Sjogren et al, , 1981Sjogren et al, , 1983 by'having better spatial correlation with topography in the region north of 30°N, and providing better estimates of radial gravity anomalies.…”

Section: Gravity Mapssupporting

confidence: 82%

Gravity field of venus at constant altitude and comparison with Earth

Bowin¹,

Abers²,

Shure³

1985

J. Geophys. Res.

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The acceleration (gravity) anomaly estimates by spacecraft tracking, determined from Doppler residuals, are components of the gravity field directed along the spacecraft‐earth line‐of‐sight (LOS). These data constitute a set of vector components of a planet's gravity field, the specific component depending upon where the earth happened to be at the time of each measurement, and they are at varying altitudes above the planet surface. From this data set we have solved for the gravity field using the method of harmonic splines, which imposes a smoothness criterion to select a gravity model compatible with the LOS data. Maps of geoid and gravity at spacecraft and at constant altitudes are presented for the planet Venus. For Venus, the major geoid and gravity anomalies each coincide spatially with the locations of positive topographic features. These anomalies at 300 km altitude have significantly greater magnitude than anomalies that on earth are coincident with topographic features. Another striking difference is that most of the major geoid anomalies on the earth do not coincide with locations of its largest topographic features, including continents, but are due to deep sources. On Venus, major mass anomalies appear to be restricted principally to the surficial 200 km of the planet. A substantially thicker crust on Venus (70–80 km), compared to the earth's (5–40 km), can explain its greater range of gravity anomaly and the positive correlation of gravity anomaly withtopographic height. Four regions with high gravity to topography response functions are interpreted to be due to crustal loading by recent volcanism perhaps combined with regional elevation of surface topography by thermal expansion from heating at depth.

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Section: Gravity Mapssupporting

confidence: 82%

Gravity field of venus at constant altitude and comparison with Earth

Bowin¹,

Abers²,

Shure³

1985

J. Geophys. Res.

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“…The raw Doppler data were reduced with the Jet Propulsion Laboratory double precision orbit determination program (DPODP) [Moyer, 1971], which has a weighted least squares filter and accounts for the many known effects on the radio signal and spacecraft motion such as earth rotation, spacecraft orbital motion, signal transit times, planetary perturbations, relativity, and Venusian atmosphere. The error in the atmospheric model discussed by Sjogren et al [1980] was shown to have a negligible effect. Each orbit was analyzed independently.…”

Section: Data Reductionmentioning

confidence: 56%

Venus gravity anomalies and their correlations with topography

Sjogren¹,

Bills²,

Birkeland³

et al. 1983

J. Geophys. Res.

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This report provides a summary of the high‐resolution gravity data obtained from the Pioneer Venus Orbiter radio tracking data. Gravity maps, covering a 70° latitude band through 360° of longitude, are displayed as line‐of‐sight and vertical gravity. Topography converted to gravity and Bouguer gravity maps are also shown in both systems. Topography to gravity ratios are made over several regions of the planet. There are markedly different ratios for the Aphrodite area as compared to the Beta and Atla areas.

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“…-2 An important difference between Venus and Earth is the strong positive correlation that exists between long-wavelength gravity and topography on Venus (Sjogren et al, 1980). This relationship is evident in comparisons of spatial domain maps (Mottinger et al, 1985, Fig.…”

mentioning

confidence: 85%

A dynamic model of Venus's gravity field

Kiefer

Richards

Hager

et al. 1986

Geophysical Research Letters

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Unlike on Earth, long‐wavelength gravity anomalies and topography correlate well on Venus. Venus's admittance curve from spherical harmonic degree 2 to 18 is inconsistent with either Airy or Pratt isostasy but is consistent with dynamic support from mantle convection. A model using whole mantle flow and a high viscosity near‐surface layer overlying a constant viscosity mantle reproduces this admittance curve. On Earth, the effective viscosity deduced from geoid modeling increases by a factor of 300 from the asthenosphere to the lower mantle. These viscosity estimates may be biased by neglect of lateral variations in mantle viscosity. The different effective viscosity profiles for Earth and Venus may reflect their convective styles, with tectonism and mantle heat transport dominated by hot plumes on Venus and by subducted slabs on Earth.

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Gravity anomalies on Venus

Cited by 57 publications

References 13 publications

Gravity field of venus at constant altitude and comparison with Earth

Gravity field of venus at constant altitude and comparison with Earth

Venus gravity anomalies and their correlations with topography

A dynamic model of Venus's gravity field

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