Solar Terrestrial Activity Report [Image] Last update October 28, 2001 at 03:35 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 unsettled on October 27. Solar wind speed ranged between 359 and 439 km/sec under the influence of a weak coronal stream. A strong solar wind shock was observed at SOHO at 02:33 UTC on October 28. The interplanetary magnetic field swung strongly southwards and this could initially cause at least major geomagnetic storming. The source of this disturbance is the halo CME originating from region 9672 on October 25. Solar flare activity was low. Solar flux was 246.5, the planetary A index was 6 (3-hour K indices: 1212 3222, Boulder K indices: 1212 3212). Region 9670 decayed further and is about to rotate off the visible disk. Region 9672 decayed slowly but could still produce a major flare. Region 9673 was quiet and stable. Region 9676 was quiet and stable. Region 9677 decayed further and was spotless by the end of the day. Region 9678 decayed significantly and lost its magnetic delta structure. Minor M class flares are possible from this region. Region 9679 and 9681 decayed slowly and quietly. Region 9682 developed fairly quickly and is an impressive region with a strong magnetic delta structure. Major proton flares are possible and likely, particularly if the current rate of development continues. Region 9683 decayed slowly and quietly. New region 9684 rotated partly into view at the northeast limb. Magnetograms indicate that the region has mixed polarities and has minor M class flaring potential. Flares and CMEs A total of 8 C class events were recorded on October 27. Region 9678 produced a C6.3 flare at 08:21 and a C3.8 flare at 16:35 UTC. Region 9672 generated a C3.6 flare at 12:27 and a C4.2 flare at 18:46 UTC. Region 9682 was the source of a C7.2 flare at 15:28 UTC. The background x-ray flux is at the class C2 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to major storm on October 28 and quiet to active on October 29. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair but is rapidly deteriorating and will become useless within a few hours. 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 9670 2001.10.16 6 S17W74 0190 FAO 9672 2001.10.18 11 S18W53 0450 DKI beta-gamma-delta 9673 2001.10.18 1 N04W49 0090 HSX 9674 2001.10.19 S08W71 plage 9675 2001.10.20 S12W25 plage 9676 2001.10.20 1 N16W21 0030 HSX 9677 2001.10.21 4 N23W19 0010 BXO now spotless 9678 2001.10.23 43 N07W07 0630 EKC beta-gamma 9679 2001.10.23 10 S10E07 0030 DSO 9680 2001.10.23 N22E09 plage 9681 2001.10.25 5 S23W22 0040 DAO 9682 2001.10.25 28 N12E45 0990 EKI beta-gamma-delta 9683 2001.10.26 5 N28E14 0010 CSO 9684 2001.10.27 1 N05E78 0140 HHX beta-gamma? Total number of sunspots: 115 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) 2001.10 205.9 (1) 168.9 (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]