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Variations of the coefficient J2 of geopotential, and the dynamical Love number k2d from the analysis of laser ranging to LAGEOS 1 and LAGEOS 2

Transactions of IAA RAS, issue 25, 108–128 (2012)

Keywords: Earth's satellites, geopotential, tides, Love numbers, SLR observations.

Abstract

Secular and seasonal variations of the coefficient of the geopotential are studied from the analysis of laser measurements of distances to the geodetic satellites LAGEOS 1 (1988-2003) and LAGEOS 2 (1992-2003). It is confirmed that beside the well-known annual variations with the amplitude egal 2.5 10 there also exist very significant semi-annual variations of a comparable amplitude. Phases of these two modes are such that the total effect may be described as a sharp postive splash of in August and considerably smaller variations in the rest part of year. The adopted theoretical value of the so-called dynamical Love number (a scale factor of near-diurnal oscillations aroused by the Earth's fluid core in the coefficients of the geopotential) is improved applying a simple close form of these oscillations expressed in terms of the differential angular velocities , of the fluid core. It is shown that this form is equivalent to the standard one of Fourier series in which such oscillations usually are referred to as a frequency-dependence of the Love number . The derived estimate = 0.0595 0.0007 statistically differs from the theoretical value = 0.063. Out-phase oscillation of with the period about 18.6 years and the amplitude 0.0064 0.0011 is detected giving evidence of large dissipation in the fluid core. The estimated secular trend (commonly interpreted as the effect of the so-called Post-Glacial Rebound) appears twice less than the value recommended by the standards of the International Earth Rotation S ervice (IERS) but agrees with last findings of other authors.

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G. A. Krasinsky. Variations of the coefficient J2 of geopotential, and the dynamical Love number k2d from the analysis of laser ranging to LAGEOS 1 and LAGEOS 2 // Transactions of IAA RAS. — 2012. — Issue 25. — P. 108–128.

@article{krasinsky2012,
  abstract = {Secular and seasonal variations of the coefficient of the geopotential are studied from the analysis of laser measurements of distances to the geodetic satellites LAGEOS 1 (1988-2003) and LAGEOS 2 (1992-2003). It is confirmed that beside the well-known annual variations with the amplitude egal 2.5 10 there also exist very significant semi-annual variations of a comparable amplitude. Phases of these two modes are such that the total effect may be described as a sharp postive splash of in August and considerably smaller variations in the rest part of year. The adopted theoretical value of the so-called dynamical Love number (a scale factor of near-diurnal oscillations aroused by the Earth's fluid core in the coefficients of the geopotential) is improved applying a simple close form of these oscillations expressed in terms of the differential angular velocities , of the fluid core. It is shown that this form is equivalent to the standard one of Fourier series in which such oscillations usually are referred to as a frequency-dependence of the Love number . The derived estimate = 0.0595 0.0007 statistically differs from the theoretical value = 0.063. Out-phase oscillation of with the period about 18.6 years and the amplitude 0.0064 0.0011 is detected giving evidence of large dissipation in the fluid core. The estimated secular trend (commonly interpreted as the effect of the so-called Post-Glacial Rebound) appears twice less than the value recommended by the standards of the International Earth Rotation S ervice (IERS) but agrees with last findings of other authors.},
  author = {G.~A. Krasinsky},
  issue = {25},
  journal = {Transactions of IAA RAS},
  keyword = {Earth's satellites, geopotential, tides, Love numbers, SLR observations},
  pages = {108--128},
  title = {Variations of the coefficient J2 of geopotential, and the dynamical Love number k2d from the analysis of laser ranging to LAGEOS 1 and LAGEOS 2},
  url = {http://iaaras.ru/en/library/paper/886/},
  year = {2012}
}

TY  - JOUR
TI  - Variations of the coefficient J2 of geopotential, and the dynamical Love number k2d from the analysis of laser ranging to LAGEOS 1 and LAGEOS 2
AU  - Krasinsky, G. A.
PY  - 2012
T2  - Transactions of IAA RAS
IS  - 25
SP  - 108
AB  - Secular and seasonal variations of the coefficient of the
geopotential are studied from the analysis of laser measurements of
distances to the geodetic satellites LAGEOS 1 (1988-2003) and LAGEOS
2 (1992-2003). It is confirmed that beside the well-known annual
variations with the amplitude egal 2.5 10 there also exist very
significant semi-annual variations of a comparable amplitude. Phases
of these two modes are such that the total effect may be described as
a sharp postive splash of in August and considerably smaller
variations in the rest part of year. The adopted theoretical value of
the so-called dynamical Love number (a scale factor of near-diurnal
oscillations aroused by the Earth's fluid core in the coefficients of
the geopotential) is improved applying a simple close form of these
oscillations expressed in terms of the differential angular
velocities , of the fluid core. It is shown that this form is
equivalent to the standard one of Fourier series in which such
oscillations usually are referred to as a frequency-dependence of the
Love number . The derived estimate = 0.0595 0.0007 statistically
differs from the theoretical value = 0.063. Out-phase oscillation of
with the period about 18.6 years and the amplitude 0.0064 0.0011 is
detected giving evidence of large dissipation in the fluid core. The
estimated secular trend (commonly interpreted as the effect of the
so-called Post-Glacial Rebound) appears twice less than the value
recommended by the standards of the International Earth Rotation S
ervice (IERS) but agrees with last findings of other authors.
UR  - http://iaaras.ru/en/library/paper/886/
ER  -