Solar Terrestrial Activity Report [Image] Last update October 10, 2001 at 03:55 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update 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 active on October 9. Solar wind speed ranged between 400 and 467 km/sec. Solar flare activity was moderate. Solar flux was 176.4, the planetary A index was 15 (3-hour K indices: 3234 4422, Boulder K indices: 4323 4422). Region 9641 rotated off the visible disk. Region 9648 was quiet and stable. Region 9650 decayed quietly. Region 9653 was mostly unchanged and may be capable of producing another minor M class flare. Region 9655 decayed slowly and quietly. Region 9657 was quiet and stable. New region 9658 rotated into view at the southeast limb. At least a couple of regions will be rotating into view at the east limb today and tomorrow. Flares and CMEs A total of 4 C and 1 M class events were recorded on October 9. A C7.0 flare was recorded at 07:41 UTC. SEC/NOAA places this event at region 9657, however, at that time there was a bright surge on the southwest limb, and this event was the likely cause of a slight increase in the above 10 MeV proton flux. Region 9657 produced a C2.4 flare at 22:07 UTC. Region 9653 was the source of an M1.4/2F long duration event peaking at 11:13 UTC. Moderate type II and IV radio sweeps were noted. A fairly fast full halo CME was observed in LASCO images soon after the event. This CME will impact Earth, most probably on October 11, and cause active to major geomagnetic storming, possibly with severe storming at high latitudes. October 7: A filament eruption in the southern hemisphere and near the central meridian may have produced a geoeffective CME. The absence of LASCO images at the time unfortunately makes it difficult to verify that there was such a CME. 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. Forecast The geomagnetic field is expected to be quiet to active on October 10. A CME impact is expected on October 11 and will probably cause active to major storm conditions. A coronal stream will likely arrive on October 12 and cause unsettled to active conditions. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 9641 2001.09.27 1 S12W89 0060 HSX 9642 2001.09.29 N05W66 plage 9646 2001.10.01 N13W67 plage 9647 2001.10.02 S18W60 plage 9648 2001.10.02 2 S07W20 0030 CSO 9650 2001.10.03 10 S16W07 0030 CSO 9651 2001.10.04 S25W81 plage 9652 2001.10.04 N21W52 plage 9653 2001.10.04 8 S22E11 0190 DAO 9654 2001.10.05 N07W45 plage 9655 2001.10.06 4 S22E26 0090 DAO 9656 2001.10.07 S21W41 plage 9657 2001.10.08 3 N23E58 0040 CSO 9658 2001.10.09 1 S14E68 0150 HAX Total number of sunspots: 29 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) 2001.10 185.9 (1) 54.1 (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]