Accession Number : AD0800002

Title :   PRINCIPLES OF A DISCRIMINATION BETWEEN SQ AND SD ON INDIVIDUAL RECORDS AND DESCRIPTION OF A SPECIAL TYPE OF MAGNETIC DISTURBANCE, THE 'SLOW OSCILLATION'. (PRINCIPES D'UNE DISCRIMINATION ENTRE SQ ET SD SUR LES ENREGISTREMENTS INDIVIDUELS ET DESCRIPTION D'UN TYPE SPECIAL DE PERTURBATION MAGNETIQUE, LES 'OSCILLATIONS LENTES'),

Descriptive Note : Research translation,

Corporate Author : AMERICAN METEOROLOGICAL SOCIETY BOSTON MA

Personal Author(s) : Mayaud, P. -N.

Report Date : JUN 1966

Pagination or Media Count : 45

Abstract : The results of an investigation made from the individual records of various observatories aiming at a discrimination between the daily variations Sq and SD are set forth. From the models of currents which represent these statistical variations, some criteria of identification of each one are defined; their confrontation with the individual records shows that they must be modified for the variation SD. In particular, on the individual records the SD-type variations present a universal time component clearly predominant; furthermore, it is shown that the zero level chosen for the statistical variation SD is arbitrary, because the low latitude effects of perturbations caused by an eastward aruoral electrojet are much more intense than those of the perturbations caused by a westward auroral electrojet. The existence of the universal time component makes the discrimination between Sq and SD much easier than could be expected. Finally, a new type of perturbations (the slow oscillations) is described; this phenomenon, made up generally of a maximum and minimum on the H-component, with (approximately) a duration of 6 to 8 hours and an amplitude of 20 gammas, is probably of an exospheric origin. (Author)

Descriptors :   (*MAGNETIC STORMS, DIURNAL VARIATIONS), GEOMAGNETISM, PERIODIC VARIATIONS, AURORAE, EXOSPHERE, RADIO TRANSMISSION, SOLAR DISTURBANCES, OSCILLATION.

Subject Categories : Geomagnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE