The Irregular Geomagnetic Fluctuations on Quiet Days in Moderately Low Latitudes

Abstract

The quiet day mean diurnal inequality of the geomagnetic horizontal intensity at a low latitude station is denoted by the Sq-field. However, it was pointed out recently that even during a period of universal magnetic calm a feeble geomagnetic agitation in auroral and equatorial zones subsists (1). Due to this agitation the geomagnetic S field at low latitude stations are found to differ systematically from the average Sq-field. That this difference, attributed to quiet day irregular geomagnetic fluctutaions, is not negligible but considerable and exhibits a diurnal and seasonal characteristic is illustrated in the analysis of data from eleven observatories situated in moderately low latitude with fairly spaced longitudinal distribution. Although an explanation of the existence and origin of these fluctuations is not possible at the moment, it is felt that a detailed study of its characteristics will contribute towards better understanding of the morphological aspects of the weak fields responsible for these fluctuations. © 1966, Society of Geomagnetism and Earth, Planetary and Space Sciences. All rights reserved.