The digital recording system operated at the U.K. magnetic observatories

A digital recording system has been operated at the U.K. observatories since 1979. The magnetic elementsH, D, andZ are monitored continuously by a triaxial fluxgate magnetometer operating in the variometer mode. Ordinate values are recorded at 30-sec intervals. Total field and the temperature of the variometer chamber are measured at the start of each 10-min data block.Fluxgate magnetometer baseline values are derived from absolute measurements made by proton vector magnetometer and Kew declinometer in the conventional manner.In this paper the data handling procedures are described and the quality of the data over a period of two years is discussed.