Solar Terrestrial Activity Report [Image] Last update December 8, 2001 at 05:20 UTC. Minor update posted at 06:37 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 7. Solar wind speed ranged between 431 and 495 km/sec. Solar flare activity was low. Solar flux was 225.9, the planetary A index was 5 (3-hour K indices: 2101 2222, Boulder K indices: 2111 3232). Region 9716 rotated quietly off the visible disk. Region 9717 decayed slowly and was mostly quiet. Region 9718 decayed significantly and has early on Dec.8 been eclipsed by reg.9727 as the largest region on the disk. Occasional minor M class flares are possible. Region 9720 was quiet and stable as were regions 9721, 9723 and 9724. Region 9726 developed slowly and quietly. Region 9727 was mostly unchanged and remains capable of producing M class flares. Region 9728 was quiet and stable. Region 9729 decayed and appears to be spotless early on Dec.8. Region 9731 was quiet and stable. Region 9732 at the northeast limb was finally numbered. Another, and more significant region is rotating into view at the northeast limb. This region could produced M class flares. Comment added at 06:37 UTC on December 8: The region at the northeast limb produced a long duration event which currently has reached the M3.4 level. See GOES SXI image produced by SEC/NOAA. Flares and CMEs A total of 4 C class events were recorded on December 7. A long duration eruption near region 9729 peaking at 03:07 was associated with a weak type II radio sweep and possibly a small partial halo CME. Region 9717 generated a C3.9/1F long duration event peaking at 05:28 UTC. Region 9727 produced a C8.2/2F flare at 08:17 UTC. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on December 8-10. There is a minor chance of a weak CME impact on December 10. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair. 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 9716 2001.11.25 1 S05W86 0010 AXX 9717 2001.11.27 1 N05W61 0110 HSX 9718 2001.11.27 17 S06W51 0540 DKI beta-gamma 9720 2001.11.28 9 S26W41 0070 DSO 9721 2001.11.28 4 N12W37 0130 CAO 9723 2001.12.01 5 S04W38 0040 DRO 9724 2001.12.01 6 N10W07 0060 DSO 9726 2001.12.02 7 S16E03 0080 DSO 9727 2001.12.03 8 S22E16 0430 DKC beta-gamma-delta 9728 2001.12.04 5 N36W47 0110 EAO 9729 2001.12.05 1 N23W22 0020 HRX now spotless? 9730 2001.12.05 S12E21 plage 9731 2001.12.06 3 N24E23 0030 DSO 9732 2001.12.07 3 N03E64 0070 DSO Total number of sunspots: 70 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) 2001.12 234.9 (1) 51.9 (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]