The files are formatted as follows:
Field Char. - Year 4 - Month 2 - Day 2 - Free 1 - K-values 8 - Free 2 - Daily Ak 3For further details, see:
Nevanlinna, H., Ketola, A. and Kangas, T., 1992. Magnetic results from Helsinki magnetic-meteorological observatory. Part I: Declination 1844-1853. Finn. Met. Inst. - Geophys. Publ. 27, 155 p.
Nevanlinna, H., Ketola, A., L. Hkkinen, A. Viljanen, and Ivory, K., 1992. Magnetic results from Helsinki magnetic-meteorological observatory. Part II: Geomagnetic activity 1844-1856. Finn. Met. Inst. - Geophys. Publ. 30, 65 p.
Nevanlinna, H. and Ketola, A., 1993. Magnetic results from Helsinki magnetic-meteorological observatory. Part III: Declination 1854-1880. Geomagnetic activity 1844-1880. Finn. Met. Inst. - Geophys. Publ. 33, 193 p.
Nevanlinna, H. and Kataja, E., 1993. An extension of the geomagnetic activity index series aa from two solar cycles (1844-1868). Geophys. Res. Lett., 20, 2703-2706.
Nevanlinna, H. and Ketola, A., 1994. Magnetic results from Helsinki magnetic- meteorological observatory. Part IV: Declination 1880-1909. Summary of observations 1844-1909. Finn. Met. Inst. - Geophys. Publ. 36, 143 p.