Equinoctial Asymmetry of Horizontal Component of Solar Quiet Variation (SqH)

Abstract

Intermagnetic data was used to obtained hourly values of solar quiet variation of horizontal component of geomagnetic field for 2009. The results obtained from the variability of the amplitude of the solar quiet SqH daily variation was examined. The SqH strength ranges between 90nT and 50nT at Adds Ababa and Guam with low strength values in other stations (Kakioka, Sodankyla, and Guam) around the local noon. The SqH are grouped into two 50nT-70nT and 70nT -90nT at Adds Ababa Kakioka, Sodankyla, Guam and Uppsala. For 50nT -70nT, It  was observed that the SqH occurrence is higher in winter and summer at SqH1 (AAE) than spring and Autumn, while SqH2 (KAK) and SqH3 (SOD) has no values of occurrence of  SqH.  In SqH4 (GUAM), SqH occurrence is higher in Winter and Autumn than Spring and Summer. In SqH5 (UPP), five occurrence of SqH was noticed in winter while other seasons have no occurrence. While 70nT and 90nT, it was noticed that Spring and summer are enhanced in SqH than Autumn and Winter at SqH1 (AAE), with no value of SqH at SqH2, SqH3 and SqH5, while SqH4 with two occurrence of SqH in Autumn while other seasons have no occurrence.  This implies that ionospheric conditions have a direct influence on the occurrence of SqH.

Keywords: solar quiet variation (SqH), Season variation and ionospheric condition