In the last decades, palaeomagnetic research has provided important information about the past variation of the Earth’s magnetic field (EMF) from its origin to the present day. However, questions regarding the origin and evolution of the EMF as well as the frequency and spatial distribution of its variations still remain open to debate. This Special Publication provides new insights into the study of the temporal and spatial evolution of the EMF presenting new data from palaeomagnetic and rock magnetic studies of archaeological materials, sediments and lavas. The papers presented cover a wide range of topics related to archaeology, stratigraphy and climate, including new data from several parts of the world, such as Europe, Africa, Australia, New Zealand, India and the Baltic Sea. This Special Publication aims to present an overview of the most recent secular variation studies and their use to disclose fundamental properties of the EMF evolution.

Earth’s magnetic field is currently changing dramatically. Is the observed decrease of the dipole moment indicating a future polarity transition? What would be the effects of such a drastic change on system Earth? Can any positive or negative effects on our biosphere or even humans be expected? This book gives a first overview about the geomagnetic field in general and serves as an introduction into geomagnetism. As the topic of the book covers a wide range of scientific disciplines, the first chapter summarises basic principles of geomagnetism and related fields including a historic overview, instruments and measurements, paleomagnetic fields, basics of dynamo theory, etc. The contributed chapters review major results of international activities aiming at understanding the causes and effects of geomagnetic field variations in view of the questions above.

The Earth's Magnetic Field : Its History, Origin, and Planetary Perspective

An interdisciplinary review of research in geomagnetism, aeronomy and space weather, written by eminent researchers from these fields.

Solar and geomagnetic variability are of considerable interest for scientists of many different persuasions and indeed one has the distinct impression that for the sun at least, there is direct relevance for mankind in general as the interrelation between solar and terrestrial phenomena is starting to be appreciated. From the vast time scale of interest in the variability field, attention was confined to the last 10,000 years in a NATO Advanced Research Workshop held from April 6 - 10, 1987 in Durham, England, and the present publication comprises the lectures given there. Such a Workshop was very timely in view of the impressive new data available from 14C analysis in dated tree rings and lOBe in polar ice cores, from natural palaeomagnetic records in lacustrine sediments and from archaeomagnetic material. Also to be mentioned are new studies of historical accounts of naked-eye sunspots and aurorae. All the data have contributed to improvements in under standing the relative variations of solar properties, the geomagnetic field and climate and it is hoped that this volume will convey the flavour of these advances in knowledge. A feature of the Workshop was the lively discussions which followed so many of the papers. There were several instances of healthy disagreement and this is reflected in the opposing views presented inanumber of the papers published here.

Treatise on Geophysics: Geomagnetism, Volume 5, provides an overview of the most important aspects of geomagnetism. The book begins by tracing the history of the study of geomagnetism. It then reviews global models of the Earth's magnetic field; the main sources of external magnetic field contributions; and the instruments and practices used to observe and measure the full range of features of the geomagnetic field. It discusses the origins of current knowledge of the secular variation of the Earth's magnetic field; crustal magnetism; geomagnetic excursions; the study of geophysical electromagnetic induction; the magnetization process; and the status of recent magnetic field data and their applications. The remaining chapters cover the geometry of the geomagnetic field and its temporal variability as recorded in volcanic and sedimentary rocks over the past few million years; the ocean crust as a recorder of geomagnetic field variations; and the theoretical basis for paleointensity experiments in igneous and sedimentary environments. The final chapter explains the concept of true polar wander (TPW), defined as shifts in the geographic location of Earth's daily rotation axis and/or by fluctuations in the spin rate (length of day anomalies). - Self-contained volume starts with an overview of the subject then explores each topic with in depth detail - Extensive reference lists and cross references with other volumes to facilitate further research - Full-color figures and tables support the text and aid in understanding - Content suited for both the expert and non-expert

This survey summarizes what is known about the magnetic field of the earth, based on information available through 1971. Observed phenomena are described and interpreted in terms of the most widely accepted physical explanations. An overview of the geomagnetic field and its dynamic relationship with its terrestrial and interplanetary environment is first presented as briefly as possible, followed by more detailed descriptions of geomagnetic measurements and experimental methods, precise current models and past behavior of the main field, regular variations in the field resulting from the motion of the earth, disturbance variations of the field produced by interplanetary environment, and dynamic processes occurring in the outer magnetosphere. Extensive references is a replacement for Chapter 11 of Handbook of Geophysics and Space Environment (Shea L. Valley, ed.), Air Force Cambridge Research Laboratories and McGraw-Hill Book Co., New York, 1965.

This 1994 book examines how reversals of the Earth's magnetic field have played a major role in establishing plate tectonics and a geological time scale.

Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 201. Modeling the Ionosphere-Thermosphere System brings together for the first time a detailed description of the physics of the IT system in conjunction with numerical techniques to solve the complex system of equations that describe the system, as well as issues of current interest. Volume highlights include discussions of: Physics of the ionosphere and thermosphere IT system, and the numerical methods to solve the basic equations of the IT system The physics and numerical methods to determine the global electrodynamics of the IT system The response of the IT system to forcings from below (i.e., the lower atmosphere) and from above (i.e., the magnetosphere) The physics and numerical methods to model ionospheric irregularities Data assimilation techniques, comparison of model results to data, climate variability studies, and applications to space weather Providing a clear description of the physics of this system in several tutorial-like articles, Modeling the Ionosphere-Thermosphere System is of value to the upper atmosphere science community in general. Chapters describing details of the numerical methods used to solve the equations that describe the IT system make the volume useful to both active researchers in the field and students.

This reference encompasses the fields of Geomagnetism and Paleomagnetism in a single volume. Both sciences have applications in navigation, in the search for minerals and hydrocarbons, in dating rock sequences, and in unraveling past geologic movements such as plate motions they have contributed to a better understanding of the Earth. The book describes in fine detail the current state of knowledge and provides an up-to-date synthesis of the most basic concepts. It is an indispensable working tool not only for geophysicists and geophysics students but also for geologists, physicists, atmospheric and environmental scientists, and engineers.