Solar Terrestrial Activity Report [Image] Last update December 12, 2001 at 05:10 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 on December 11. Solar wind speed ranged between 306 and 357 km/sec. Solar flare activity was high. Solar flux was 220.6, the planetary A index was 4 (3-hour K indices: 1101 1222, Boulder K indices: 0211 1221). Region 9721 rotated quietly over the northwest limb. Region 9724 was quiet and stable. Region 9727 was mostly unchanged and remains capable of producing a major proton flare. Region 9732 was quiet and stable. Region 9733 developed slowly and could produce another major flare. Region 9734 was quiet and stable. Region 9735 decayed into spotless plage. Region 9736 developed slowly and quietly. Region 9737 developed further and could produce C flares. A new region is rotating into view at the southeast limb. Flares and CMEs A total of 4 C, 1 M and 1 X class events were recorded on 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.) Region 9727 generated an M1.3/2N flare at 14:51 UTC. The background x-ray flux is at the class C1 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 unsettled on December 12 and quiet to active on December 13-14 due to a coronal stream. There is a minor 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 fair to good. 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 9720 2001.11.28 S28W86 plage 9721 2001.11.28 2 N11W93 0050 HSX 9724 2001.12.01 1 N08W61 0050 HSX 9726 2001.12.02 S16W50 plage 9727 2001.12.03 26 S21W37 0570 EKC beta-gamma-delta 9729 2001.12.05 N23W74 plage 9730 2001.12.05 S12W31 plage 9731 2001.12.06 N25W30 plage 9732 2001.12.07 2 N04E08 0060 CSO 9733 2001.12.08 31 N14E32 0470 EAI beta-gamma-delta 9734 2001.12.09 1 S12E52 0070 HAX 9735 2001.12.10 N10W47 plage 9736 2001.12.10 6 S10W42 0030 DAO 9737 2001.12.10 5 S27E39 0120 DSO Total number of sunspots: 74 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) 2001.12 229.9 (1) 78.4 (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]