Linear filters as a method of real-time prediction of geomagnetic activity

Conference · Tue Jan 01 00:00:00 EST 1985

DOI:https://doi.org/10.1007/978-94-009-4722-1_5· OSTI ID:5692779

McPherron, R L; Baker, D N; Bargatze, L F

Important factors controlling geomagnetic activity include the solar wind velocity, the strength of the interplanetary magnetic field (IMF), and the field orientation. Because these quantities change so much in transit through the solar wind, real-time monitoring immediately upstream of the earth provides the best input for any technique of real-time prediction. One such technique is linear prediction filtering which utilizes past histories of the input and output of a linear system to create a time-invariant filter characterizing the system. Problems of nonlinearity or temporal changes of the system can be handled by appropriate choice of input parameters and piecewise approximation in various ranges of the input. We have created prediction filters for all the standard magnetic indices and tested their efficiency. The filters show that the initial response of the magnetosphere to a southward turning of the IMF peaks in 20 minutes and then again in 55 minutes. After a northward turning, auroral zone indices and the midlatitude ASYM index return to background within 2 hours, while Dst decays exponentially with a time constant of about 8 hours. This paper describes a simple, real-time system utilizing these filters which could predict a substantial fraction of the variation in magnetic activity indices 20 to 50 minutes in advance.

• Research Organization: California Univ., Los Angeles (USA). Inst. of Geophysics and Planetary Physics; Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5692779
• Report Number(s): LA-UR-85-1305; CONF-850277-2; ON: DE85010760
• Resource Relation: Journal Volume: 126; Conference: Chapman conference on solar wind-magnetosphere energy coupling, Pasadena, CA, USA, 12 Feb 1985; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
GEOMAGNETIC FIELD
MATHEMATICAL MODELS
SOLAR WIND
COMPUTERIZED SIMULATION
FORECASTING
INTERPLANETARY MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MAGNETOSPHERE
REAL TIME SYSTEMS
EARTH ATMOSPHERE
FLUID MECHANICS
HYDRODYNAMICS
MAGNETIC FIELDS
MECHANICS
SIMULATION
SOLAR ACTIVITY
640203* - Atmospheric Physics- Magnetospheric Phenomena- (-1987)