Tidal deceleration of the Moon's mean motion

Abstract

S U M M A R YThe secular change in the mean motion of the Moon, ri, caused by the tidal dissipation in the ocean and solid Earth is due primarily to the effect of the diurnal and semidiurnal tides. The long-period ocean tides produce an increase in ti, but the effects are only 1 per cent of the diurnal and semidiurnal ocean tides. In this investigation, expressions for these effects are obtained by developing the tidal potential in the ecliptic reference system. The computation of the amplitude of equilibrium tide and the phase corrections is also discussed. The averaged tidal deceleration of the Moon's mean motion, ri, from the most recent satellite ocean tide solutions is -25.25 f 0.4 arcseconds/century'. The value for ri inferred from the satellite-determined ocean tide solution is in good agreement with the value obtained from the analysis of 20 years of lunar laser ranging observations.

Gravity model development for TOPEX/POSEIDON: Joint Gravity Models 1 and 2

“…Recent geopotential solutions have directly estimated a set of resonant spherical harmonic terms in the tidal expansion for major tidal constituents [cf. Marsh et al, 1988;1990a;Christodoulidis et al, 1988;Cheng et al, 1992].…”

The flux of tidal energy across latitude 60°S

“…An important constraint in resolving these questions is the total global rate of the tidal energy loss, and this is now well established: 2.5 + 0.1 terawatts (TW) for the principal lunar semidiurnal tide (M2) [e.g., Ray, 1994]. This rate is deduced from observations of the secular acceleration of the moon [Dickey et al, 1994], from observations of long-period perturbations in the orbits of artificial satellites [e.g., Cheng et al, 1992], and from direct calculations of the rate of working of tidal forces on the oceans [Cartwright and Ray, 1991]. Note that the latter tells us the rate at which energy is input to the oceans, but it tells us nothing about how or where that energy is consumed.…”

Earth Rotation Variations – Long Period

“…Of primary importance in this regard is the value for the tidal acceleration _ n of the Moon since it controls the long-term behavior of the Moon's motion. Other SLR-derived values for _ n have been reported by Cheng et al (1990Cheng et al ( , 1992, Marsh et al (1990Marsh et al ( , 1991, Dickman (1994), Lerch et al (1994), and Ray (1994). Tidal forces distort the figure of the Earth and hence its gravitational field, which in turn perturbs the orbits of artificial satellites.…”