Solar Terrestrial Activity Report [Image] Last update December 28, 2001 at 04:25 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 unsettled on December 27. Solar wind speed ranged between 332 and 396 km/sec. Solar flare activity was moderate. Solar flux was 274.6, the planetary A index was 6 (3-hour K indices: 2112 2331, Boulder K indices: 2112 3332). Region 9742 is rotating over the northwest limb but remains capable of producing major flares. Regions 9743 and 9745 decayed and were spotless by early evening. Region 9747 decayed into spotless plage. Region 9748 was mostly unchanged and could produce minor M class flares. Region 9751 developed early in the day and appeared to be decaying later on. M class flaring is possible. Spotless region 9752 was very active early in the day and produced several flares. Region 9753 was quiet and stable. Region 9754 decayed slowly but could still produce a minor M class flare. Region 9755 was quiet and stable, as was region 9756. Region 9757 decayed and could soon become spotless. Regions 9760 and 9761 were quiet and stable. New region 9762 emerged in the northeast quadrant near the center of the solar disk. New region 9763 rotated into view at the northeast limb. Flares and CMEs A total of 8 C and 3 M class events were recorded on December 27. Region 9752 produced a C5.7 flare at 03:45, an M1.4/2N flare at 06:!3 and a C4.5 flare at 08:02 UTC. Region 9742 generated an M1.0 flare at 11:33 UTC. Region 9754 was the source of a C9.0 flare at 15:31 and a C6.5 flare at 20:27 UTC. Region 9748 produced an M2.3/2N long duration event peaking at 16:58 UTC, while region 9743 managed a C4.7 flare at 21:43 UTC. Region 9742 generated an impulsive M4.7 flare at 03:51 UTC on December 28. December 26: Region 9742 produced a major flare, a long duration M7.1/1B proton event (with associated strong type II and IV sweeps) peaking at 05:40 UTC. A partial halo coronal mass ejection was associated with the flare, it is uncertain if the fast CME is geoeffective. If it is the magnetosphere could receive an impact on December 28 or 29 causing unsettled to minor (perhaps even major) geomagnetic storming. The background x-ray flux is at the class C3 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to minor storm on December 28-29 and quiet to unsettled on December 30. 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 9742 2001.12.15 14 N12W81 0690 EKI beta-gamma-delta 9743 2001.12.16 1 S09W74 0050 HSX now spotless 9745 2001.12.18 2 N18W62 0010 BXO now spotless 9747 2001.12.19 N12W39 plage 9748 2001.12.20 16 S11W64 0330 EAO beta-gamma 9749 2001.12.20 S08W22 plage 9751 2001.12.21 38 N04W10 0410 EAI beta-gamma 9752 2001.12.22 S13W85 plage 9753 2001.12.22 12 S18W06 0050 DSO 9754 2001.12.23 23 S08E11 0140 EAI beta-gamma 9755 2001.12.25 8 S04E37 0150 CAO 9756 2001.12.26 1 S29E60 0070 HSX 9757 2001.12.26 6 S08W12 0020 CRO 9758 2001.12.26 N13E07 plage 9759 2001.12.26 N17E15 plage 9760 2001.12.26 4 N07E21 0020 CRO 9761 2001.12.26 1 N10E61 0050 HSX 9762 2001.12.27 1 N03E07 0020 HSX 9763 2001.12.27 1 N06E76 0060 HSX Total number of sunspots: 128 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 (109.3 predicted, +0.6) 2001.07 131.3 82.2 (109.8 predicted, +0.5) 2001.08 162.9 106.8 (110.3 predicted, +0.5) 2001.09 233.2 150.7 (109.7 predicted, -0.6) 2001.10 207.6 125.6 (107.0 predicted, -2.7) 2001.11 210.6 106.5 (105.3 predicted, -1.7) 2001.12 232.2 (1) 188.1 (2) (102.0 predicted, -3.3) 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]