Solar Terrestrial Activity Report [Image] Last update October 22, 2001 at 03:30 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update October 3, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update October 3, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update October 3, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update October 16, 2001)] Recent development The geomagnetic field was quiet to severe storm on October 21. Solar wind speed ranged between 317 and 690 km/sec. A strong solar wind shock was observed at SOHO at 16:05 UTC. Solar wind speed increased abruptly from 380 to 590 km/sec. The interplanetary magnetic field swung very strongly southwards causing minor to severe geomagnetic storming. The source of the shock was the halo CME observed after the first X1 flare on October 19. Solar flare activity was moderate. Solar flux was 224.1, the planetary A index was 40 (3-hour K indices: 2332 3667, Boulder K indices: 2233 3566). Region 9658 decayed and rotated quietly off the visible disk. Region 9661 redeveloped a magnetic delta structure and will likely produce further M class flares. Region 9662 rotated quietly over the northwest limb. Region 9667 was quiet and stable. Region 9669 decayed slowly and quietly. Region 9670 developed more spots and could produce occasional M class flares. Region 9671 decayed slowly and was quiet. Region 9672 developed slowly and could be capable of producing a major flare. Region 9673 was quiet and stable, as were regions 9674, 9675 and 9676. Flares and CMEs A total of 8 C and 2 M class events were recorded on October 21. Region 9672 produced a C4.3 flare at 00:11 UTC. Region 9661 generated an M2.5/2N flare at 11:36 UTC. Region 9670 was the source of a C2.5 flare at 13:26 UTC. An optically unassigned M1.3 flare was recorded at 05:18 UTC. Another flare of interest was a C7.8 event at 04:37 UTC, this flare was accompanied by a weak type II radio sweep. October 19: Region 9661 produced an X1.6/2B flare at 01:05 UTC. A strong type II and a moderate type IV radio sweep accompanied the event. A full halo CME was observed in LASCO images. The CME will impact Earth, most likely during the latter half of October 21, and cause active to major geomagnetic storming. Region 9661 produced another major X1.6/2B flare at 16:30 UTC. This flare was associated with moderate type II and IV radio sweeps and a full halo CME. The CME will impact Earth, probably on October 22, and prolong the geomagnetic storm started by the CME from the first X1 flare. 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 unsettled to major storm on October 22 and quiet to minor storm on October 23. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor to useless. 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 9658 2001.10.09 1 S15W86 0050 HAX 9661 2001.10.10 10 N14W64 0360 EKO beta-gamma-delta 9662 2001.10.11 1 N11W88 0020 HAX 9663 2001.10.11 S16W69 plage 9666 2001.10.14 S11W60 plage 9667 2001.10.14 2 N26W23 0010 HRX 9668 2001.10.15 N29W77 plage 9669 2001.10.15 35 N14W12 0110 EAI 9670 2001.10.16 27 S18E06 0390 FAO beta-gamma 9671 2001.10.17 10 N15W22 0050 DSO 9672 2001.10.18 14 S19E26 0330 DKO 9673 2001.10.18 6 N03E32 0140 CSO 9674 2001.10.19 7 S09E07 0080 DSO 9675 2001.10.20 1 S13E56 0030 HSX 9676 2001.10.20 5 N13E58 0090 DSO Total number of sunspots: 119 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 2000.09 182.1 109.7 116.3 (-2.3) 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 (107.7 predicted, +2.9) 2001.05 147.1 96.6 (108.1 predicted, +0.4) 2001.06 173.0 134.0 (106.3 predicted, -1.8) 2001.07 131.3 82.2 (105.1 predicted, -1.2) 2001.08 162.9 106.8 (105.7 predicted, +0.6) 2001.09 233.2 150.7 (105.1 predicted, -0.6) 2001.10 197.1 (1) 125.5 (2) (102.3 predicted, -2.8) 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]