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Table 1

Number of foF2 anomalies, with duration greater than 3 h, classified with respect to the corresponding geomagnetic activity level, together with the yearly values of the F10.7 solar index, the a p geomagnetic index and the number of foF2 anomalies with a minimum duration of 1 h.

Year Geomagnetic conditions No. of foF2 anomalies with a duration greater than 3 h Yearly mean value of solar index F10.7 Yearly mean value of a p index Yearly number of foF2 anomalies with a minimum duration of 1 h
1985 QUIET 3 74.9 13.7 155
G0 AE > 100 nT 51
G1 10
G2 13
G3 4
1986 QUIET 4 73.8 12.5 143
G0 AE > 100 nT 43
G1 10
G2 3
G3 1
G4 1
G5 1
1987 QUIET 10 86.2 10.9 146
G0 AE > 100 nT 42
G1 12
G2 6
1995 QUIET 5 76.9 12.6 120
G0 AE > 100 nT 12
G1 14
G2 5
G4 1
1996 QUIET 5 71.9 9.3 107
G0 AE > 100 nT 40
G1 5
G2 1
1997 QUIET 3 81.6 8.4 101
G0 AE > 100 nT 29
G1 3
G2 2
G3 4
2007 QUIET 18 73.1 7.5 108
G0 AE > 100 nT 26
G1 8
G2 1
2008 QUIET 12 68.7 6.9 77
G0 AE > 100 nT 22
G1 3
G2 1
2009 QUIET 31 70.8 3.9 83
G0 AE > 100 nT 15
G1 1

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