Solar Terrestrial Activity Report [Image] Last update October 24, 2001 at 02:10 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 minor storm on October 23. Solar wind speed ranged between 397 and 552 km/sec. Solar flare activity was high. Solar flux was 226.4, the planetary A index was 15 (3-hour K indices: 4532 2221, Boulder K indices: 4443 1221). Region 9661 rotated quietly off the visible disk. Region 9667 decayed slowly and could become spotless today. Region 9669 decayed slowly and quietly. Region 9670 was mostly unchanged and remains capable of producing occasional M class flares. Region 9671 decayed slowly and will likely become spotless today. Region 9672 maintained a strong magnetic delta structure and could produce further major flares. Region 9673 was mostly quiet and stable, as were regions 9675 and 9676. Region 9674 decayed and was spotless by early afternoon. Region 9677 developed slowly and quietly. New region 9678 emerged fairly quickly in the northeast quadrant. New region 9679 emerged near the southeast limb. New region 9680 emerged near the northeast limb. Flares and CMEs A total of 8 C and 2 M class events were recorded on October 23. Region 9672 produced an M1.3 flare at 00:23, an M6.5/1B flare at 02:23 (no obvious CME was observed after this event), a C4.4 flare at 12:08, a C6.7 flare at 12:29, a C2.0 flare at 14:17 and a C2.3 flare at 15:12 UTC. Region 9678 generated a C2.3 flare at 06:07 UTC. Region 9676 was the source of a C7.7/1F flare at 08:03 UTC. October 22: Region 9672 was the source of a major M6.7/2N long duration event peaking at 15:08 (with associated weak type IV and moderate type II radio sweeps) and a major X1.2/2B flare at 17:59 UTC (with an associated weak type II radio sweep). A large and bright full halo CME was observed in LASCO C3 images after the M6 event. This CME will impact Earth, most likely during the latter half of October 24. The background x-ray flux is at the class C1 level. Coronal holes What could be a coronal hole in the northern hemisphere will rotate into a geoeffective position on October 23-24. Forecast The geomagnetic field is expected to be quiet to major storm on October 24-25 with a possibility of severe storm intervals. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very 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 9661 2001.10.10 2 N14W90 0190 CKO 9666 2001.10.14 S11W86 plage 9667 2001.10.14 1 N25W50 0000 AXX 9669 2001.10.15 10 N13W39 0070 CAO 9670 2001.10.16 22 S18W20 0450 FKI beta-gamma 9671 2001.10.17 3 N14W52 0010 AXX 9672 2001.10.18 20 S18E00 0420 DKO beta-gamma-delta 9673 2001.10.18 8 N02E05 0110 CAO 9674 2001.10.19 1 S08W21 0010 AXX now spotless 9675 2001.10.20 1 S12E28 0020 HSX 9676 2001.10.20 1 N14E30 0050 HSX 9677 2001.10.21 8 N21E33 0040 CSO 9678 2001.10.23 10 N07E48 0050 CAO 9679 2001.10.23 3 S10E58 0010 BXO 9680 2001.10.23 1 N22E61 0010 AXX Total number of sunspots: 91 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) 2001.10 200.0 (1) 139.6 (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]