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Home > Publication > Memoirs of the Kakioka Magnetic Observatory > Memoirs of the Kakioka Magnetic Observatory Vol.22 No.02 >A New Method to Determine K-Indices by Using Geomagnetic One-Minute Data

Memoirs of the Kakioka Magnetic Observatory Vol.22 No.02, p.45, March, 1988


A New Method to Determine K-Indices by Using Geomagnetic One-Minute Data


Kadokura, S.


Abstract

 A New method to estimate the solar regular daily variations of geomagnetic field (SR) by using geomagnetic one-minute data was developed and applied to derivation of K-indices. The procedure for obtaining SR consists of 3 steps ;selecting quiet N days' data {qi} i=I,N on the basis of K-indices, building up the orthogonal normal set {qi} i=I.N of SR, and calculating the SR of each day as the linear combination of {qi} i=I,N whose coefficients are defined by the inner products of bi and the one-minute data of the relevant day. The digital K-indices (K') by this method were compared with hand scaled indices at Kakioka (KAK) in 1986. The occurrences of the cases |K -K'|= 0, 1, and 2 are adout 70%, 30%, and 1% respectively. It indicates an agreement better than the previous methods applied to low and middle latitude. K-indices at Memambetsu (MMB) and Kanoya (KNY),which are close to Kakioka, were also compared with KAK. The differences of the K-indices between KAK and KNY,or that between KAK and MMB are in the distributions similar to |K - K'|at KAK. This fact indicates that the K' may be indices equivalent to K.



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