Period | Trend (MHz/year) |
---|
1960 to 1986 | -0.018 |
1960 to 1989 | -0.016 |
1960 to 1996 | -0.010 |
1960 to 2000 | -0.009 |
1960 to 2009 | -0.006 |
- foF2 trend values were estimated after filtering foF2 12-month running mean at 12 LT with F10.7 for the period beginning in 1960 and ending in 1986 (minimum between cycles 21 and 22), in 1989 (maximum of cycle 22), in 1996 (minimum between cycles 22 and 23), in 2000 (maximum of cycle 23), and in 2009 (minimum between cycles 23 and 24).