Solar Terrestrial Activity Report [Image] Last update October 12, 2001 at 03:45 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 July 27, 2001)] Recent development The geomagnetic field was quiet to minor storm on October 11. Solar wind speed ranged between 344 and 600 km/sec. A fairly strong solar wind shock was observed at SOHO at 16:12 UTC. Solar wind speed increased abruptly from 350 to 540 km/sec and the interplanetary magnetic field swung strongly southwards. The source of the shock was the full halo CME observed on October 9. Solar flare activity was low. Solar flux was 174.8, the planetary A index was 17 (3-hour K indices: 2321 3554, Boulder K indices: 2322 3543). Region 9648 decayed slowly and could become spotless today. Region 9650 decayed and was spotless by early evening. Region 9653 decayed slowly and quietly. Region 9655 was quiet and stable. Magnetograms indicate that region 9655 is the trailing spot group of region 9653. Region 9657 was mostly quiet and stable. Region 9658 developed slowly and may be capable of minor M class flare production. Region 9659 decayed and was spotless by early evening. Region 9660 developed slowly and quietly. Region 9661 rotated fully into view revealing a fairly strong magnetic delta structure within the largest penumbra. M class flares are possible. New region 9662 emerged in the northeast quadrant. New region 9663 rotated into view at the southeast limb. Flares and CMEs A total of 6 C class events were recorded on October 11. Region 9657 produced a C4.6 flare at 04:25 UTC, a weak type II radio sweep was recorded as well. Region 9661 generated a C2.1 flare at 17:43 UTC and was the likely source of a long duration C4.1 event peaking at 07:29 UTC. Region 9658 produced a C1.1 flare at 22:08 while region 9663 managed a C1.3 flare at 22:45 UTC. The background x-ray flux is at the class B8 level. Coronal holes A coronal hole in the northern hemisphere was in a geoeffective position on October 9-10. A coronal hole in the southern hemisphere will rotate into a geoeffective position on October 12-13. Forecast The geomagnetic field is expected to be unsettled to major storm on October 12 and unsettled to active on October 13. 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 no. Location region numbered sunspots at Area Classification Comment midnight 9647 2001.10.02 S18W86 plage 9648 2001.10.02 1 S07W48 0010 HSX 9650 2001.10.03 4 S16W34 0020 BXO now spotless 9652 2001.10.04 N21W78 plage 9653 2001.10.04 15 S22W14 0150 DAO 9654 2001.10.05 N07W71 plage 9655 2001.10.06 5 S22E00 0090 CSO 9656 2001.10.07 S21W67 plage 9657 2001.10.08 7 N19E23 0030 DSO 9658 2001.10.09 9 S15E44 0190 FAI 9659 2001.10.10 2 N03E04 0010 BXO now spotless 9660 2001.10.10 10 N12E08 0030 DAO 9661 2001.10.10 5 N16E69 0480 FXO beta-delta 9662 2001.10.11 5 N09E42 0020 BXO 9663 2001.10.11 1 S13E67 0020 HRX Total number of sunspots: 64 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. 2000.07 202.3 170.1 119.7 2000.09 182.1 109.7 116.3 (-2.3) 2000.10 167.4 99.4 114.5 (-1.8) 2000.11 178.8 106.8 112.8 (-1.7) 2000.12 173.6 104.4 112.1 (-0.7) 2001.01 166.6 95.6 108.8 (-3.3) 2001.02 146.6 80.6 104.1 (-4.7) 2001.03 177.7 113.5 104.8 (+0.7) 2001.04 177.7 108.2 (107.7 predicted, +2.9) 2001.05 147.1 97.3 (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) 2001.10 184.2 (1) 64.0 (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] [StudyWeb]