Solar Terrestrial Activity Report [Image] Last update December 27, 2001 at 01:25 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 26. Solar wind speed ranged between 365 and 429 km/sec. Solar flare activity was high. Solar flux was 267.8, the planetary A index was 7 (3-hour K indices: 2001 2332, Boulder K indices: 2111 2432). Region 9742 developed a magnetic delta structure at the east edge of the southern leading spot group and is capable of producing another major proton flare. Region 9743 was quiet and stable, as was region 9745. Region 9747 decayed slowly and quietly. Region 9748 was mostly unchanged and can produce minor M class flares. Region 9751 developed fairly quickly and has two magnetic delta structures. Major flares are possible. Region 9752 once again decayed into spotless plage. Region 9753 developed slowly and quietly. Region 9754 was mostly unchanged and remains capable of minor M class flare production. Region 9755 was quiet and stable. New region 9756 rotated into view at the southeast limb. New region 9757 emerged in the southeast quadrant near the central meridian. New regions 9758, 9759 and 9760 emerged in the northeast quadrant. New region 9761 rotated into view at the northeast limb. Regions 9757, 9758, 9759 and 9760 were all apparently spotless early on Dec.27. Flares and CMEs A total of 4 C and 1 M class events were recorded on December 25. Region 9742 finally 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. The above 100 MeV proton flux peaked at 50 pfu while the above 10 MeV peaked at above 700 pfu. 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 geomagnetic storming. The region was the source of an M1.8/1F flare at 12:26, a C7.4 flare at 14:12 and an M1.3 flare at 17:18 UTC. as well. Region 9751 generated a C6.2 flare at 00:10 and a C8.2 flare at 03:36 UTC. Region 9748 produced an M1.2 flare at 21:15 UTC. An impressive full halo CME was observed on December 25. Its source was on the backside of the sun, approximately 2-4 days behind the southeast limb. The background x-ray flux is at the class C3-C4 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 27 and most of December 28. There is a 50% chance of a glancing blow from the partial halo CME observed on Dec.26. 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 25 N12W68 0470 EKI beta-gamma-delta 9743 2001.12.16 2 S09W60 0070 CSO 9745 2001.12.18 3 N18W50 0010 DRO 9746 2001.12.19 S17W84 plage 9747 2001.12.19 1 N12W26 0010 HRX 9748 2001.12.20 18 S10W48 03+0 DAO beta-gamma 9749 2001.12.20 S08W09 plage 9751 2001.12.21 33 N04E04 0500 EKI beta-gamma-delta 9752 2001.12.22 S13W72 plage 9753 2001.12.22 15 S19E09 0050 DSO 9754 2001.12.23 26 S09E24 0200 EAI beta-gamma 9755 2001.12.26 6 S04E50 0200 CAO 9756 2001.12.27 1 S28E72 0040 HSX 9757 2001.12.27 3 S09E02 0010 CSO now spotless 9758 2001.12.27 1 N13E20 0000 AXX now spotless 9759 2001.12.27 2 N17E28 0010 BXO now spotless 9760 2001.12.27 3 N06E35 0010 CRO now spotless 9761 2001.12.27 1 N09E75 0050 HSX Total number of sunspots: 140 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) 2001.12 230.5 (1) 185.5 (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]