Solar Terrestrial Activity Report [Image] Last update December 26, 2001 at 04:30 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 25. Solar wind speed ranged between 392 and 520 km/sec under the weakening influence of a coronal stream. Solar flare activity was moderate. Solar flux was 258.8, the planetary A index was 8 (3-hour K indices: 3213 2213, Boulder K indices: 3223 3322). Region 9742 is developing a magnetic delta structure at the east edge of the southern leading spots group. The region still has major flare potential. Region 9743 decayed slowly and quietly. Region 9745 decayed and could become spotless today. Region 9747 decayed slowly and quietly. Region 9748 developed slowly and can produce M class flares. Region 9751 developed slowly and could produce minor M class flares. Region 9752 once again reemerged with a couple of spots. Region 9753 decayed slowly and quietly. Region 9754 developed further and can produce further M class flares. Flares and CMEs A total of 4 C and 1 M class events were recorded on December 25. Region 9748 produced a C8.0 flare at 00:37 and a C9.8/1F flare at 20:37 UTC. Region 9754 generated an M1.2/1F flare at 07:08 and a C7.5/1F flare at 23:14 UTC. Region 9742 was the source of a C5.4 flare at 12:05 UTC. December 23: Region 9748 produced a C4.9 flare at 03:57. A weak geoeffective CME may have been associated with this event, a coronal wave was observed in EIT images. 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 unsettled on December 26-28. 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 no. Location at region numbered sunspots midnight Area Classification Comment 9742 2001.12.15 49 N12W57 1070 FKC beta-gamma 9743 2001.12.16 4 S09W46 0100 CAO 9745 2001.12.18 4 N19W38 0010 CSO 9746 2001.12.19 S17W71 plage 9747 2001.12.19 4 N12W10 0030 DSO 9748 2001.12.20 23 S10W36 0320 EAO beta-gamma 9749 2001.12.20 S08E04 plage 9751 2001.12.21 25 N04E18 0380 EKI beta-gamma 9752 2001.12.22 2 S13W59 0010 BXO 9753 2001.12.22 7 S18E12 0040 DSO 9754 2001.12.23 25 S09E38 0270 EAI beta-gamma 9755 2001.12.25 3 S05E64 0180 CAO Total number of sunspots: 146 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) 2001.12 229.1 (1) 170.1 (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]