On 26-month periodicity in quiet-day range of geomagnetic horizontal force and in sunspot number

摘要: In view of conflicting and inconclusive evidence on the existence a quasi-biennial cycle in geomagnetic field search has been made for 26-month oscillation using an extensive series data covering 61 yr from Alibag Observatory. To ascertain if is solar origin, relative sunspot number same period also analysed identical method. It concluded that small but significant amplitude occurs quiet-day range horizontal force Earth's magnetic appears to be origin. The investigation reveals 16-month unknown both number.