Technical Report of the Kakioka Magnetic Observatory, Vol. 9, No.1-2, pp. 7-17, February, 2012

Proposition for improving measurements and data processing for the Overhauser magnetometers in KASMMER



   Renewal of the Kakioka Automatic Standard MagnetoMetER (KASMMER) from 1992 to 1993 involved installing Overhauser magnetometers (OHM) to replace the optical pumping magnetometers (OPM). Although the OPMs were updated with OHMs, the method for continuous measurement of the three geomagnetic components remains unchanged, with the three components derived from total magnetic intensity measured by a magnetometer fitted with a compensating coil. However, because of restrictions such as differences in the magnetometersf measurement ranges, measurement and processing methods have been slightly changed, and it cannot be said that the magnetic component values are the same as before in terms of precision. In particular, it is problematic that the scattering of D-component (magnetic declination) values has increased. In addition, it is difficult to make up for a missing component if one or of the four OHMs malfunctions, and the D-component is particularly likely to be missing. In this paper, we propose methods to address these two shortcomings.

Received 11 November 2010; received in revised form 26 August 2011; accepted 14 October 2011

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