# DOI: https://doi.org/10.5880/Kp.0001 # LICENCE: CC BY 4.0, please cite: # Matzka, J., Bronkalla, O., Tornow, K., Elger, K. and Stolle, C., 2021. # Geomagnetic Kp index. V. 1.0. GFZ Data Services, # https://doi.org/10.5880/Kp.0001 # Matzka, J., Stolle, C., Yamazaki, Y., Bronkalla, O. and Morschhauser, A., # 2021. The geomagnetic Kp index and derived indices of geomagnetic activity. # Space Weather, https://doi.org/10.1029/2020SW002641 # The Kp index was introduced by Bartels (1949) and is produced by Geomagnetic # Observatory Niemegk, GFZ German Research Centre for Geosciences. International Quietest Days Most Disturbed Days Month Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 D1 D2 D3 D4 D5 Jan 1985 7 6 18 5 20K 26 19A 24A 4A 16A 28 9 23 1 10 Feb 1985 4 18 26 19A 16A 22A 23A 3A 21A 15A 28 6 10 8 5 Mar 1985 13 9 22 20 21 23 24K 25K 11K 14A 5 8 6 7 2 Apr 1985 15 18 17 12 6 13 5A 7A 16A 14A 21 28 20 30 9 May 1985 30 29 28 22 23 10K 24 27 11 20 2 15* 12* 13* 16* Jun 1985 16 19 14 3 18 5 13 4 24 15K 10 7 6 26 28* Jul 1985 2 22 16 29 21 3K 19A 15A 20A 9A 12 31 4 6 13 Aug 1985 6 5 7 9 11K 8 3 4 24A 10A 13 31 22 29* 12 Sep 1985 4 5 2 3 29 30 13 18 12 1 19 16 14 20 21 Oct 1985 1 30 26 27 28 2 20 31 10 9 5 6 7 18 13 Nov 1985 20 23 24 12 21 25 26K 8K 7A 28A 30 29 2 3 13 Dec 1985 8 23 7 21 9 16 25K 22 29A 6A 30 19 28 13 31