The Earth's Variable Rotation: Geophysical Causes and Consequences

by Kurt Lambeck

• ISBN13: 9780521673303
• ISBN10: 0521673305
• Format: Paperback
• Copyright: 2005-06-30
• Publisher: Cambridge University Press

Summary

Astronomers have long noted that the Earth does not rotate uniformly about an axis fixed in the planet, that both the length-of-day and the direction of the rotation axis vary periodically and irregularly by small amounts. These variations are an immediate consequence of the Earth not being a rigid body. In this book Professor Lambeck discusses the irregular nature of this motion and the geophysical mechanisms responsible for it. A complete analysis of these causes requires a discussion of solid Earth physics, magnetohydrodynamics, oceanography and meteorology. The study of the Earth's rotation is therefore of interest not only to astronomers who wish to explain their observations, but also to many geophysicists who use the astronomers' observations to understand better the Earth's response to a variety of applied forces. The author emphasizes the important contributions made over the last 15 years, this progress being in part a consequence of the overall progress in geophysics and planetary physics and of the developments in space science and technology, which not only require that the Earth's motion be precisely known but which also have provided new and precise methods for monitoring this motion. This book is suitable for geophysicists, astronomers and geodesists who are actively engaged in research as well as for graduate students.

Table of Contents

Preface	ix
A perspective	1	(5)
Some physical properties of the Earth	6	(24)
Elastic deformation	6	(7)
Anelastic deformation	13	(8)
The core	21	(4)
Gravity field	25	(5)
Rotational dynamics	30	(17)
Rigid body rotation	30	(3)
Non-rigid body rotation: general formulation	33	(4)
Rotation of spheroid with fluid core	37	(2)
Rotational deformation	39	(5)
Damped linear motion	44	(3)
Excitation functions	47	(15)
Alternative formulations	47	(3)
Surface loading	50	(2)
Schematic excitation functions	52	(10)
The astronomical evidence	62	(45)
Observations of the Earth's rotation	62	(11)
Length-of-day	73	(12)
Polar motion	85	(19)
New observation techniques	104	(3)
Tides	107	(39)
Earth tides	109	(10)
Ocean and atmospheric tides	119	(13)
Satellite observations of tidal parameters	132	(6)
Tidal perturbations in rotation	138	(8)
Seasonal variations	146	(49)
Atmospheric pressure	147	(12)
Groundwater	159	(4)
Oceans	163	(3)
Winds	166	(13)
Astronomical and geophysical comparisons	179	(11)
Non-seasonal meteorological exictations in l.o.d.	190	(5)
The Chandler wobble	195	(50)
The Chandler period of the solid Earth	196	(7)
Dissipation in the solid Earth	203	(8)
The pole tide	211	(9)
Excitation of the Chandler wobble	220	(25)
Decade fluctuations	245	(41)
Core-mantle coupling	246	(22)
Oceanic and atmospheric contributions	268	(14)
Earthquakes	282	(1)
Conclusions	283	(3)
Tidal dissipation	286	(56)
Introduction	286	(4)
The problem	290	(9)
Astronomical evidence	299	(20)
Ocean tide dissipation	319	(15)
Discussion	334	(8)
Paleorotation	342	(59)
Polar wander	342	(10)
Tidal accelerations in the geological past	352	(8)
Paleontological clocks	360	(28)
Paleorotation and the lunar orbit	388	(13)
Bibliography	401	(36)
Author index	437	(8)
Subject index	445