13 
second order. Minute mean values of the magnetometer and the base line instruments were 
processed, which had been synchronized within ±5 s. 
For 1995 to 1999, the base line values of the primary components refer to the following 
equivalent voltages Eof the fluxgate compensation fields: 
Component 
Ein mV (nominal) 
U 
12861 
V 
12613 
Z 
45463 
4.2 Scale values, temperature coefficients and cross talk 
Scale values and cross talk were traced back to the respective parameters of the old 
FM100C(EDA) system by employing stochastic methods, making use of strong variations during a 
substorm on April 7, 1995 (Schulz, 1998a; see also appendix 3). The following values apply to the 
primary components (FGE125): 
Scale Values in 10 nT/mV 
1.000+ 
Cross Talk against FM100C in 10' 3 
U 
+10' 3 (1.4 ±0.6) 
V: +0.2±1.0 
Z: +0.9±0.6 
V 
-10' 3 (1.5 ±0.8) 
U: -0.7±0.6 
Z: -0.5±0.4 
Z 
+10' 3 (0.8 ±0.4) 
U: -0.6±0.4 
V: -0.5±0.6 
Considering the respective values of the FM100C (see yearbook No 41, 1995), the absolute 
misalignments and errors of the scale values of the FGE125 fluxgates probably do not exceed the 
order of magnitude of 10' 3 . 
Temperature coefficients were neglected because the FGE double system had been installed in 
the old variometer room with almost perfect temperature control (contact thermometers, ±0.03°C). 
5 Data processing 
The base line values (Tables 1 .x) were smoothed by Bathspline approximation in steps of 0.01' 
for Dor 0.1 nT for Hand Z, respectively (Schott, 1992). 
Hourly mean values were formed using 60 minute mean values of U, V, and Z (taken at minutes 
00 to 59 UTC and centred at second 30) as well as 60 F spot values (taken at second 05). 
The international quiet (Q) and disturbed (D) days were taken from the Gottingen (1996) and 
Potsdam (since 1997) Listings of ISGI, respectively. 
The data were processed by a computer double system of type HP9000 330/360. Each 
workstation is connected to a data acquisition unit of type HP3852 and to BSH by X25 computer 
link. All necessary calculations including those for the yearbook were carried out by the workstation 
of type HP9000 360.