Analysis on the Temporal-Spatial Distribution of the Geomagnetic Activity Index Vr

摘要

References(8) Based on the analysis of the Vr index from data from geomagnetic observatories in China and four geomagnetic observatories abroad, temporal-spatial distribution characteristics of Vr index were analyzed. The Vr index showed 27-day solar-cycle recurrences and significant seasonal variation. It also increased with latitude. Meanwhile, both local-time dependence and an obvious dusk-dawn asymmetry existed, which might be related to the asymmetric ring current, the partial ring current, and the field-aligned current.