Forced nutations of the Earth: Influence of inner core dynamics: 3. Very long interferometry data analysis

We discuss the analysis of 798 very long baseline interferometry (VLBI) experiments carded out between July 1980 and February 1989, and the determination from this analysis of corrections to selected coefficients in the International Astronomical Union (IAU) 1980 theory of the nutations of the Earth. Our analysis confirms earlier VLBI results and indicates that most of these corrections can be explained by carefully accounting for (1) corrections to the IAU 1980 rigid-Earth nutation series, (2) the presence of the Earth's inner core, (3) the difference between the dynamic flattening of the Earth inferred from the precession constant and that inferred from seismic models of the internal density structure of the Earth, and (4) the effects of mantle anelasticity and ocean tides. The standard deviations of the corrections to the coefficients are 0.04 milliarcseconds (mas) for terms with periods under 430 days, and 1.0 mas for the terms with a period of 18.6 years. The unresolved issues raised by our analysis are the origins of corrections to the out-of-phase retrograde annual(0.39 mas) and the in-phase prograde 13.66 day (− 0.25 mas) nutations. Our analysis also yields a correction to the IAU 1976 value for the luni-solar precession constant of −0.32±0.13 arc sec/century (cy).

[1]  E. C. Pavlis,et al.  A new gravitational model for the earth from satellite tracking data - GEM-T1 , 1988 .

[2]  V. Dehant.  On the nutations of a more realistic earth model , 1990 .

[3]  M. E. Parke.  O1, P1, N2 models of the global ocean tide on an elastic earth plus surface potential and spherical harmonic decompositions for M2, S2, and K1 , 1982 .

[4]  John M. Wahr,et al.  The forced nutations of an elliptical, rotating, elastic and oceanless earth , 1981 .

[5]  J. Wahr,et al.  A diurnal resonance in the ocean tide and in the Earth's load response due to the resonant free ‘core nutation’ , 1981 .

[6]  J. G. Williams,et al.  Tidal variations of earth rotation , 1981 .

[7]  P. M. Mathews,et al.  Forced nutations of the Earth: Influence of inner core dynamics: 2. Numerical results and comparisons , 1991 .

[8]  Thomas A. Herring,et al.  Erratum: Correction to ``Geodesy by Radio Interferometry: Studies of the forced nutations of the Earth, 1, Data Analysis'' , 1986 .

[9]  E. W. Schwiderski,et al.  On charting global ocean tides , 1980 .

[10]  I. Shapiro,et al.  VLBI limits on the proper motion of the ‘core’ of the superluminal quasar 3C345 , 1986, Nature.

[11]  J. Wahr,et al.  The effects of the solid inner core and nonhydrostatic structure on the Earth's forced nutations and Earth tides , 1991 .

[12]  G W Swenson,et al.  Real-Time, Very-Long-Baseline Interferometry Based on the Use of a Communications Satellite , 1977, Science.

[13]  J. Wahr.  The theory of the earth's orientation, with some new results for nutation , 1988 .

[14]  I. Shapiro,et al.  Geodesy by Radio Interferometry: Intercontinental Distance Determinations With Subdecimeter Precision- (Paper 80B 1609) , 1981 .

[15]  A E Rogers,et al.  Quasars Revisited: Rapid Time Variations Observed Via Very-Long-Baseline Interferometry , 1971, Science.

[16]  T. Sasao,et al.  A Simple Theory on the Dynamical Effects of a Stratified Fluid Core upon Nutational Motion of the Earth , 1980 .

[17]  J. Wahr,et al.  An excitation mechanism for the free ‘core nutation’ , 1981 .

[18]  R. Hellings,et al.  Relativistic effects in astronomical timing measurements. , 1986 .

[19]  W. J. Eckert,et al.  Transformations of the lunar coordinates and orbital parameters , 1966 .

[20]  Y. Kubo.  Perturbations by the oblateness of the Earth and by the planets in the motion of the Moon , 1982 .

[21]  S. C. Unwin,et al.  Superluminal expansion of quasar 3C273 , 1981, Nature.

[22]  J. Zensus,et al.  Superluminal Radio Sources , 1988 .

[23]  D. Robertson,et al.  Geodetic radio interferometric surveying: Applications and results , 1985 .

[24]  M. Rochester.  The Secular Decrease of Obliquity due to Dissipative Core—Mantle Coupling , 1976 .

[25]  J. Wünsch,et al.  Periodic changes in Earth's rotation due to oceanic tides , 1989 .

[26]  T. Lederle,et al.  Expressions for the precession quantities based upon the IAU /1976/ system of astronomical constants , 1977 .

[27]  F. Dahlen,et al.  The period and Q of the Chandler wobble , 1981 .

[28]  J. Chapront,et al.  The lunar ephemeris ELP 2000. , 1983 .

[29]  H. Frey,et al.  Space-Age Geodesy: The NASA Crustal Dynamics Project , 1985, IEEE Transactions on Geoscience and Remote Sensing.

[30]  James L. Davis,et al.  Geodesy by radio interferometry: The application of Kalman Filtering to the analysis of very long baseline interferometry data , 1990 .

[31]  H. Kinoshita.  Theory of the rotation of the rigid earth , 1977 .

[32]  P. Bretagnon.  Theorie du mouvement de l'ensemble des planetes (VSOP82). , 1982 .

[33]  C. Reigber,et al.  Various aspects of numerical determination of nutation constants. II - an improved nutation series for the deformable earth , 1990 .

[34]  P. K. Seidelmann,et al.  1980 IAU Theory of Nutation: The final report of the IAU Working Group on Nutation , 1982 .

[35]  J. Wahr,et al.  The earth's forced nutations - Geophysical implications , 1990 .

[36]  John M. Wahr,et al.  The effects of mantle anelasticity on nutations, earth tides, and tidal variations in rotation rate , 1986 .

[37]  T. Jordan,et al.  Frequency dependence of QScS , 1979 .

[38]  E. Groten,et al.  Various aspects of numerical determination of nutation constants. I - Improvement of rigid-earth nutation , 1989 .

[39]  Thomas A. Herring,et al.  Geodesy by radio interferometry: Studies of the forced nutations of the Earth. II: Interpretation , 1986 .

[40]  J. Souchay,et al.  The theory of the nutation for the rigid earth model at the second order , 1990 .

[41]  Tsutomu Sasao,et al.  Note on nutation in ephemerides. , 1979 .

[42]  H. Schuh,et al.  IRIS‐S: Extending geodetic Very Long Baseline Interferometry observations to the southern hemisphere , 1988 .

[43]  I. Shapiro,et al.  Geodesy by radio interferometry: Effects of atmospheric modeling errors on estimates of baseline length , 1985 .

[44]  Thomas A. Herring,et al.  Forced nutations of the Earth: Influence of inner core dynamics: 1. Theory , 1991 .

[45]  P. Melchior.  Precession-nutations and tidal potential , 1971 .

[46]  X. X. Newhall,et al.  Luni-solar precession - Determination from lunar laser ranges , 1991 .

[47]  John M. Wahr,et al.  Body tides on an elliptical, rotating, elastic and oceanless earth , 1981 .

[48]  I. Shapiro,et al.  "Correction [to “Geodesy by radio interferometry: Studies of the forced nutations of the Earth, 1. Data analysis” by T. A. Herring, C. R. Gwinn and I. I. Shapiro]"" , 1986 .

[49]  T. Jordan,et al.  Regional variation of QScS , 1980 .

[50]  R. Sailor,et al.  Measurements and interpretation of normal mode attenuation , 1978 .