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.
[Full text (PDF; in Japanese; size:11966KB)]
Copyright (c) 2014 Kakioka Magnetic Observatory, Japan Meteorological Agency. All Rights Reserved.
