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Nonlinear ARMA models for the D(st) index and their physical interpretationTime series models successfully reproduce or predict geomagnetic activity indices from solar wind parameters. A method is presented that converts a type of nonlinear filter, the nonlinear Autoregressive Moving Average (ARMA) model to the nonlinear damped oscillator physical model. The oscillator parameters, the growth and decay, the oscillation frequencies and the coupling strength to the input are derived from the filter coefficients. Mathematical methods are derived to obtain unique and consistent filter coefficients while keeping the prediction error low. These methods are applied to an oscillator model for the Dst geomagnetic index driven by the solar wind input. A data set is examined in two ways: the model parameters are calculated as averages over short time intervals, and a nonlinear ARMA model is calculated and the model parameters are derived as a function of the phase space.
Document ID
19970016608
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Vassiliadis, D.
(Universities Space Research Association Greenbelt, MD United States)
Klimas, A. J.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Baker, D. N.
(Colorado Univ. Boulder, CO United States)
Date Acquired
August 17, 2013
Publication Date
October 1, 1996
Subject Category
Geophysics
Accession Number
97N19049
Funding Number(s)
CONTRACT_GRANT: NRA-94-SSM SR/T-046
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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