Solar Terrestrial Activity Report [Image] Last update December 13, 2001 at 01:15 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update December 2, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update December 2, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update December 2, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update October 16, 2001)] Recent development The geomagnetic field was quiet to minor storm on December 12. Solar wind speed ranged between 309 and 380 km/sec. An unexpected and short lasting disturbance arrived early in the day and peaked before noon. Solar flare activity was high. Solar flux was 222.6 (the 18h UTC measurement was used because the 20h UTC value was flare enhanced), the planetary A index was 12 (3-hour K indices: 2225 3233, Boulder K indices: 1235 3122). Region 9724 decayed and was quiet, the region will rotate out of view late today. Region 9727 developed slowly and is likely to produce further major flares. Proton flares are possible as well. Region 9732 was quiet and stable. Region 9733 was mostly unchanged and remains capable of at least M class flaring. Region 9734 decayed slowly and quietly. Region 9735 reemerged with a couple of spots. Region 9736 developed slowly. Region 9737 decayed slowly and was quiet. New region 9738 rotated into view at the southeast limb. Flares and CMEs A total of 8 C and 3 M class events were recorded on December 12. Region 9736 produced a C3.7 flare at 00:11 and a C5.6 flare at 04:56 UTC. Region 9727 generated a C3.4 flare at 03:50, a C3.2 flare at 08:53, a C9.3 flare at 20:24, a major M5.6 flare (see GOES SXI image from SEC/NOAA) at 22:00 (with no significant CME observed in LASCO images) and an M4.8 flare (image) at 23:22 UTC. Region 9733 was the source of a C4.8 flare at 12:28 and an M3.0/1N flare (image) at 19:11 UTC. December 11: Region 9733 produced a major impulsive X2.8/2B flare at 08:08. This event was accompanied by a moderate type II and a weak type IV radio sweep. A slow partial halo CME was observed off the northeast limb and the north pole. It is uncertain if this CME had any geoeffective extensions. (A filament in the northwest quadrant erupted before noon and caused a partial halo CME off the northwest and most of the southwest limb as well as the north pole.) The background x-ray flux is at the class C2 level. Coronal holes An extension of a large southern hemisphere coronal hole was in a geoeffective position on December 10-12. Forecast The geomagnetic field is expected to be quiet to active on December 13-14 due to a coronal stream. There is a chance of a weak CME impact on December 14. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor. Coronal holes (1) Coronal mass M and X class flares (3) ejections (2) [Coronal hole indicator][CME indicator] [M and X class flare indicator] 1) Effects from a coronal hole could reach earth within the next 5 days. 2) Material from a CME is likely to impact earth within 96 hours. 3) There is a possibility of either M or X class flares within the next 48 hours. Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability. Active solar regions (Recent map) Solar Date Actual Location region numbered no. at Area Classification Comment sunspots midnight 9724 2001.12.01 1 N09W75 0030 HSX 9726 2001.12.02 S16W63 plage 9727 2001.12.03 23 S21W52 0600 EKC beta-gamma-delta 9729 2001.12.05 N23W87 plage 9730 2001.12.05 S12W44 plage 9731 2001.12.06 N25W43 plage 9732 2001.12.07 5 N04W05 0080 CSO 9733 2001.12.08 42 N14E18 0560 EKI beta-gamma-delta 9734 2001.12.09 2 S12E38 0030 CSO 9735 2001.12.10 2 N05W61 0020 BXO 9736 2001.12.10 7 S09W55 0090 DAO 9737 2001.12.10 8 S28E26 0080 DAO 9738 2001.12.12 3 S21E67 0050 CSO Total number of sunspots: 93 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.8 2000.10 167.4 99.4 114.5 (-1.8) 2000.11 178.8 106.8 112.7 (-1.8) 2000.12 173.6 104.4 112.0 (-0.7) 2001.01 166.6 95.6 108.7 (-3.3) 2001.02 146.6 80.6 104.1 (-4.6) 2001.03 177.7 113.5 104.8 (+0.7) 2001.04 177.7 107.7 107.6 (+2.8) 2001.05 147.1 96.6 108.7 (+1.1) 2001.06 173.0 134.0 (108.5 predicted, -0.2) 2001.07 131.3 82.2 (108.1 predicted, -0.4) 2001.08 162.9 106.8 (108.7 predicted, +0.6) 2001.09 233.2 150.7 (108.1 predicted, -0.6) 2001.10 207.6 125.6 (105.3 predicted, -2.8) 2001.11 210.6 106.5 (103.7 predicted, -1.6) 2001.12 229.3 (1) 84.3 (2) (100.3 predicted, -3.4) 1) Running average based on the daily 20:00 UT solar flux value at 2800 MHz. 2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-40% less. This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News]