Solar Terrestrial Activity Report [Image] Last update October 2, 2001 at 04:30 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update 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 unsettled to major storm on October 1. Solar wind speed ranged between 421 and 650 km/sec. A solar wind shock was observed at SOHO at 21:15 UTC with solar wind speed increasing abruptly from 500 to 580 km/sec. This caused a return to minor storm conditions. Solar flare activity was high. Solar flux was 216.5, the planetary A index was 50 (3-hour K indices: 4566 5435, Boulder K indices: 4365 5335). Region 9628 rotated off the visible disk producing an impressive very long duration major flare. Region 9632 did not change much and remains capable of generating a major flare until it rotates off the visible disk late today. Region 9633 was quiet and stable, as was region 9634. Region 9635 rotated quietly off the visible disk. Region 9636 decayed slightly but remains capable of minor M class flare production. Region 9637 decayed significantly and was quiet. Region 9639 was quiet and stable, as were regions 9640 and 9642. Region 9641 developed slowly and could produce minor M class flares. New region 9643 emerged in the southwest quadrant, the region is spotless early today. New region 9644 emerged in the northwest quadrant near the central meridian. New region 9645 emerged in the southeast quadrant near the central meridian. New region 9646 emerged in the northeast quadrant. At least a couple of active regions will soon rotate into view at the east limb. Flares and CMEs A total of 2 C and 4 M class events were observed on October 1. Region 9628 seems to have been the source of a major M9.1 flare peaking at 05:15 UTC. Flux levels then dropped towards the M1 level before increasing slowly to the M2.4 level around 08h UTC. This very long duration event was the source of a proton event that started after noon and has so far reached the 700 pfu level for the above 10 MeV proton flux. A large and wide full halo CME was produced and the CME could be geoeffective. Region 9636 produced an M1 flare during the decay phase of the long duration event. Region 9632 was the source of an impulsive M1.2 flare at 23:45 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 unsettled to minor storm on October 2 and quiet to active on October 3. 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 no. Location at region numbered sunspots midnight Area Classification Comment 9628 2001.09.18 15 S22W91 0350 EKC beta-gamma 9632 2001.09.20 20 S21W73 0620 EKC beta-gamma 9633 2001.09.22 1 N22W43 0070 HSX 9634 2001.09.22 10 N11W38 0070 CAO 9635 2001.09.23 4 N20W90 0090 DAO 9636 2001.09.24 34 N13W27 0310 EAC beta-gamma 9637 2001.09.24 15 S20W19 0120 ESO 9638 2001.09.25 N03W17 plage 9639 2001.09.26 4 N04W37 0060 CSO 9640 2001.09.27 3 N11E12 0040 CAO 9641 2001.09.27 9 S13E23 0220 EAO beta-gamma 9642 2001.09.29 2 N06E43 0060 HAX 9643 2001.10.01 3 S26W26 0030 BXO 9644 2001.10.01 4 N20W04 0030 CSO 9645 2001.10.01 12 S18E03 0060 DAO 9646 2001.10.01 3 N12E42 0030 CAO Total number of sunspots: 139 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) 2001.03 177.7 113.5 104.8 (+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) 2001.10 216.5 (1) 9.3 (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]