Information about K-Indices

K-indices of Magnetic Activity at Canadian Magnetic Observatories

The K-indices are computed by the Canadian Geomagnetism Program for only three Canadian observatories. Ottawa and Meanook provide K-values to the planetary Kp index. Victoria provides K-values for incorporation into other planetary indices.

The K-indices are computed automatically using the Polish algorithm (K. Nowozynski, T. Ernst and J. Jankowski, 1991. Adaptive smoothing method for computer derivation of K-indices. Geophysical Journal International, v. 104, p.85-93), one of the IAGA approved methods for computer-derivation of K-indices. The computations are carried out daily, for each Universal Time day, using data from the last 6 hours of the previous day, 24 hours of the actual day, and the first 6 hours of the following day. The K-values for each day are quoted for the eight 3-hour intervals: 00 - 03 UT, 03 - 06 UT, . . ., 21 - 00 UT.

The K-indices are normally verified by manual inspection twice per month prior to shipment to the Niemegk Observatory for incorporation into the Kp indices, and for archiving. These verified K-values are available in a series of monthly files. In the files, each line contains the 3-letter IAGA observatory code, year, month, day of month, and the eight K-indices for the day (with values ranging from 0 to 9). If a valid K-value is not available, -1 is used.

K-indices for intervals more recent than the last shipment to Niemegk are considered to be provisional. They are available in files of slightly different format (to emphasize the PROVISIONAL nature); in these files, K-indices that are suspect, or invalid, have values greater than 900. In addition, day-of-year is used instead of month and day.

IAGA Codes for Canadian Magnetic Observatories

• MEA, Meanook
• OTT, Ottawa
• VIC, Victoria