Stanford Mean Solar Magnetic Field (microTesla) 1987 Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. day 01 . 1 . 10 14 2 11 39 12 -3 . . 02 11 . . . 17 3 20 43 -3 -4 -20 . 03 . . . 8 11 12 26 27 -16 -3 -19 2 04 . 9 . 13 5 23 33 14 -19 -17 -24 . 05 6 10 . 10 0 27 33 4 -31 -28 . . 06 . 14 9 2 3 24 32 -10 . -35 -10 . 07 9 16 . -5 . 29 17 -16 -49 -28 -12 . 08 . 15 14 -14 6 38 2 -29 . -24 . . 09 12 . 15 -13 6 31 -10 -37 -50 -20 -28 . 10 13 . . -12 5 8 -13 -38 -39 -16 -28 . 11 16 10 10 -5 20 -8 -19 -36 -24 -6 -20 . 12 . . . 5 17 -17 -29 -43 -18 -3 . 19 13 20 14 10 18 5 -19 -24 -32 -10 6 . . 14 25 8 23 30 -6 -21 -22 . -1 7 4 . 15 23 7 18 30 -4 -21 -18 -19 4 -11 5 . 16 17 15 22 25 2 -16 -15 -7 -1 -9 . . 17 13 13 22 19 4 -12 -9 2 -5 -10 . 22 18 11 11 17 13 3 -16 4 6 -5 -6 . 30 19 15 12 13 6 4 -6 9 3 -8 5 18 . 20 11 11 7 2 7 9 11 -13 . 6 . 20 21 -6 . -1 -3 . 13 7 -15 -10 9 21 . 22 -4 2 1 -2 19 12 11 -18 -5 12 30 -10 23 9 2 -3 1 21 7 -5 -22 7 23 3 -17 24 . 5 2 2 . 7 -12 -25 14 25 -10 -18 25 7 4 0 6 3 11 -11 -18 19 21 . -1 26 . . 3 8 8 6 -10 -2 21 23 4 -3 27 . 4 -3 10 8 -1 -10 12 22 . 4 . 28 3 6 -2 . 12 4 -5 26 20 . . . 29 5 -1 12 17 -1 -10 33 15 15 -5 . 30 -2 7 12 16 5 6 22 5 2 . 24 31 5 12 4 27 16 4 24