Download or read book Steady Induction Effects in Geomagnetism Part 1C Geomagnetic Estimation of Steady Surficial Core Motions Application to the Definitive Geomagnetic Reference Field Models written by and published by . This book was released on 1993 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 1038 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Steady Induction Effects in Geomagnetism Part 1c written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-11 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the source-free mantle/frozen-flux core magnetic earth model, the non-linear inverse steady motional induction problem was solved using the method presented in Part 1B. How that method was applied to estimate steady, broad-scale fluid velocity fields near the top of Earth's core that induce the secular change indicated by the Definitive Geomagnetic Reference Field (DGRF) models from 1945 to 1980 are described. Special attention is given to the derivation of weight matrices for the DGRF models because the weights determine the apparent significance of the residual secular change. The derived weight matrices also enable estimation of the secular change signal-to-noise ratio characterizing the DGRF models. Two types of weights were derived in 1987-88: radial field weights for fitting the evolution of the broad-scale portion of the radial geomagnetic field component at Earth's surface implied by the DGRF's, and general weights for fitting the evolution of the broad-scale portion of the scalar potential specified by these models. The difference is non-trivial because not all the geomagnetic data represented by the DGRF's constrain the radial field component. For radial field weights (or general weights), a quantitatively acceptable explication of broad-scale secular change relative to the 1980 Magsat epoch must account for 99.94271 percent (or 99.98784 percent) of the total weighted variance accumulated therein. Tolerable normalized root-mean-square weighted residuals of 2.394 percent (or 1.103 percent) are less than the 7 percent errors expected in the source-free mantle/frozen-flux core approximation. Voorhies, Coerte V. Goddard Space Flight Center ...
Download or read book Steady Induction Effects in Geomagnetism Part 1A Steady Motional Induction of Geomagnetic Chaos written by and published by . This book was released on 1992 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1994-12 with total page 950 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1994 with total page 1688 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1994 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Steady Induction Effects in Geomagnetism Part 1b written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-11 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The problem of estimating a steady fluid velocity field near the top of Earth's core which induces the secular variation (SV) indicated by models of the observed geomagnetic field is examined in the source-free mantle/frozen-flux core (SFI/VFFC) approximation. This inverse problem is non-linear because solutions of the forward problem are deterministically chaotic. The SFM/FFC approximation is inexact, and neither the models nor the observations they represent are either complete or perfect. A method is developed for solving the non-linear inverse motional induction problem posed by the hypothesis of (piecewise, statistically) steady core surface flow and the supposition of a complete initial geomagnetic condition. The method features iterative solution of the weighted, linearized least-squares problem and admits optional biases favoring surficially geostrophic flow and/or spatially simple flow. Two types of weights are advanced radial field weights for fitting the evolution of the broad-scale portion of the radial field component near Earth's surface implied by the models, and generalized weights for fitting the evolution of the broad-scale portion of the scalar potential specified by the models. Voorhies, Coerte V. Goddard Space Flight Center RTOP 676-40-02; RTOP 579-31-07...
Download or read book Steady Induction Effects in Geomagnetism Part 1a written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-11 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geomagnetic effects of magnetic induction by hypothetically steady fluid motion and steady magnetic flux diffusion near the top of Earth's core are investigated using electromagnetic theory, simple magnetic earth models, and numerical experiments with geomagnetic field models. The problem of estimating a steady fluid velocity field near the top of Earth's core which induces the secular variation indicated by broad-scale models of the observed geomagnetic field is examined and solved. In Part 1, the steady surficial core flow estimation problem is solved in the context of the source-free mantle/frozen-flux core model. In the first paper (IA), the theory underlying such estimates is reviewed and some consequences of various kinematic and dynamic flow hypotheses are derived. For a frozen-flux core, fluid downwelling is required to change the mean square normal magnetic flux density averaged over the core-mantle boundary. For surficially geostrophic flow, downwelling implies poleward flow. The solution of the forward steady motional induction problem at the surface of a frozen-flux core is derived and found to be a fine, easily visualized example of deterministic chaos. Geomagnetic effects of statistically steady core surface flow may well dominate secular variation over several decades. Indeed, effects of persistent, if not steady, surficially geostrophic core flow are described which may help explain certain features of the present broad-scale geomagnetic field and perhaps paleomagnetic secular variation. Voorhies, Coerte V. Goddard Space Flight Center ...
Download or read book Potential Theory in Gravity and Magnetic Applications written by Richard J. Blakely and published by Cambridge University Press. This book was released on 1996-09-13 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text bridges the gap between the classic texts on potential theory and modern books on applied geophysics. It opens with an introduction to potential theory, emphasising those aspects particularly important to earth scientists, such as Laplace's equation, Newtonian potential, magnetic and electrostatic fields, and conduction of heat. The theory is then applied to the interpretation of gravity and magnetic anomalies, drawing on examples from modern geophysical literature. Topics explored include regional and global fields, forward modeling, inverse methods, depth-to-source estimation, ideal bodies, analytical continuation, and spectral analysis. The book includes numerous exercises and a variety of computer subroutines written in FORTRAN. Graduate students and researchers in geophysics will find this book essential.
Download or read book Quaternary Dating Methods written by Mike Walker and published by John Wiley & Sons. This book was released on 2013-04-30 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: This introductory textbook introduces the basics of dating, the range of techniques available and the strengths and limitations of each of the principal methods. Coverage includes: the concept of time in Quaternary Science and related fields the history of dating from lithostratigraphy and biostratigraphy the development and application of radiometric methods different methods in dating: radiometric dating, incremental dating, relative dating and age equivalence Presented in a clear and straightforward manner with the minimum of technical detail, this text is a great introduction for both students and practitioners in the Earth, Environmental and Archaeological Sciences. Praise from the reviews: "This book is a must for any Quaternary scientist." SOUTH AFRICAN GEOGRAPHICAL JOURNAL, September 2006 “...very well organized, clearly and straightforwardly written and provides a good overview on the wide field of Quaternary dating methods...” JOURNAL OF QUATERNARY SCIENCE, January 2007
Download or read book Natural Electromagnetic Fields in Pure and Applied Geophysics written by Kalyan Kumar Roy and published by Springer Nature. This book was released on 2020-02-22 with total page 605 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research monograph presents all the branches of geophysics based on natural electromagnetic fields and their associated subjects. Meant for postgraduate and research level courses, it includes research guidance and collection of magnetotelluric data in some parts of Eastern India and their qualitative and quantitative interpretation. Specific topics highlighted include (i) Electrotellurics, (ii) Magnetotellurics, (iii) Geomagnetic Depth Sounding and Magnetometer Array Studies, (iv) Audio Frequency Magnetotellurics and Magnetic Methods, (v) Marine Magnetotelluric and Marine Controlled Source Electromagnetic Methods, (vi) Electrical Conductivity of Rocks and Minerals and (vii) Mathematical Modelling and Some Topics on Inversion needed for Interpretation of Geoelectrical Data.
Download or read book Global Geodetic Observing System written by Hans-Peter Plag and published by Springer Science & Business Media. This book was released on 2009-07-25 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Global Geodetic Observing System (GGOS) has been established by the Int- national Association of Geodesy (IAG) in order to integrate the three fundamental areas of geodesy, so as to monitor geodetic parameters and their temporal varia- ?9 tions, in a global reference frame with a target relative accuracy of 10 or b- ter. These areas, often called ‘pillars’, deal with the determination and evolution of (a) the Earth’s geometry (topography, bathymetry, ice surface, sea level), (b) the Earth’s rotation and orientation (polar motion, rotation rate, nutation, etc. ), and (c) the Earth’s gravity eld (gravity, geoid). Therefore, Earth Observation on a global scale is at the heart of GGOS’s activities, which contributes to Global Change - search through the monitoring, as well as the modeling, of dynamic Earth processes such as, for example, mass and angular momentum exchanges, mass transport and ocean circulation, and changes in sea, land and ice surfaces. To achieve such an - bitious goal, GGOS relies on an integrated network of current and future terrestrial, airborne and satellite systems and technologies. These include: various positioning, navigation, remote sensing and dedicated gravity and altimetry satellite missions; global ground networks of VLBI, SLR, DORIS, GNSS and absolute and relative gravity stations; and airborne gravity, mapping and remote sensing systems.
Download or read book Summaries of Technical Reports Volume XVIII written by and published by . This book was released on 1984 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanisms of Migration in Fishes written by James D. McCleave and published by Springer Science & Business Media. This book was released on 2013-03-13 with total page 567 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last major synthesis of our knowledge of fish migration and the underlying transport and guidance phenomena, both physical and biological, was "Fish Migration" published 16 years ago by F.R. Harden Jones (1968). That synthesis was based largely upon what could be gleaned by classical fishery-biology techni.ques, such as tagging and recapture studies, commercial fishing statistics, and netting and trapping studies. Despite the fact that Harden Jones also provided, with a good deal of thought and speculation, a theoretical basis for studying the various aspects of fish migration and migratory orientation, progress in this field has been, with a few excepti.ons, piecemeal and more disjointed than might have been expected. Thus we welcomed the approach from the NATO Marine Sciences Programme Panel and the encouragement from F.R. Harden Jones to develop a proprosal for, and ultimately to organize, a NATO Advanced Research Institute (ARI) on mechanisms of fish migration. Substantial progress had been made with descriptive, analytical and predictive approaches to fish migration since the appearance of "Fish ~ligration." Both because of the progress and the often conflicting results of research, we felt that the time was again right and the effort justified to synthesize and to critically assess our knowledge. Our ultimate aim was to identify the gains and shortcomings and to develop testable hypotheses for the next decade or two.
Download or read book Near Surface Applied Geophysics written by Mark E. Everett and published by Cambridge University Press. This book was released on 2013-04-25 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: A refreshing, up-to-date exploration of the latest developments in near-surface techniques, for advanced-undergraduate and graduate students, and professionals.
