Solar Terrestrial Activity Report [Image] Last update October 1, 2001 at 02:55 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update September 1, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update September 1, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update September 1, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update July 27, 2001)] Recent development The geomagnetic field was quiet to active on September 30. Solar wind speed ranged between 452 and 582 km/sec. A solar wind shock was observed at SOHO at 18:41 UTC with solar wind speed increasing abruptly from 470 to 550 km/sec. The source of this shock was probably the partial halo CME observed after an M3 flare in region 9636 on September 28. The interplanetary magnetic field has at times been moderately to strongly southwards after the shock. Solar flare activity was moderate. Solar flux was 235.8, the planetary A index was 17 (3-hour K indices: 4322 3444, Boulder K indices: 3222 3444). Region 9628 decayed slowly but could produce a major flare while rotating off the visible disk today. Region 9632 did not change much and remains capable of generating a major flare until it rotates off the visible disk on October 2 and 3. Region 9633 was quiet and stable, as was region 9634. Region 9635 was quiet and stable and is rotating off the visible disk. Region 9636 developed further and could soon become capable of producing a major flare. Region 9637 developed slowly and was mostly quiet. Region 9639 was quiet and stable, as were regions 9640, 9641 and 9642. An active region is approaching the southeast limb. Flares and CMEs A total of 9 C and 2 M class events were observed on September 30. Region 9636 produced a C8.4 flare at 06:06, a C5.8 flare at 06:53, a C6.1 flare at 08:39 and a C4.4 flare at 18:45 UTC. Region 9637 generated a C3.3 flare at 09:42 UTC. Region 9628 was the source of an M1.0 long duration event which peaked at 11:41 and a C6.6 flare at 17:33 UTC. An optically unaccounted M1.2 flare was recorded at 21:36 UTC. The background x-ray flux is at the class C1-C2 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be unsettled to minor storm on October 1 and quiet to active on October 2. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to 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 at region numbered sunspots midnight Area Classification Comment 9627 2001.09.18 N00W88 plage 9628 2001.09.18 20 S17W76 0800 EKI beta-gamma 9632 2001.09.20 19 S18W61 0620 DKI beta-gamma 9633 2001.09.22 1 N22W29 0080 HSX 9634 2001.09.22 7 N12W29 0070 DAO 9635 2001.09.23 3 N22W78 0140 DAO 9636 2001.09.24 35 N14W15 0350 FKC beta-gamma 9637 2001.09.24 19 S13W07 0190 DAO beta-gamma 9638 2001.09.25 N03W04 plage 9639 2001.09.26 8 N04W20 0100 CSO 9640 2001.09.27 2 N10E26 0020 CSO 9641 2001.09.27 5 S15E38 0150 CSO 9642 2001.09.29 1 N04E56 0020 HSX Total number of sunspots: 120 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 2000.08 163.0 130.5 118.6 (-1.1) 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 (105.7 predicted, +1.6) 2001.04 177.7 108.2 (108.8 predicted, +3.1) 2001.05 147.1 97.3 (108.0 predicted, -0.5) 2001.06 173.0 134.0 (106.3 predicted, -1.7) 2001.07 131.3 82.2 (105.0 predicted, -1.3) 2001.08 162.9 106.8 (105.6 predicted, +0.6) 2001.09 233.2 (1) 229.1 (2) (105.0 predicted, -0.6) 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]