Solar Terrestrial Activity Report [Image] Last update October 11, 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 July 27, 2001)] Recent development The geomagnetic field was quiet to unsettled on October 10. Solar wind speed ranged between 353 and 461 km/sec. Solar flare activity was low. Solar flux was 178.7, the planetary A index was 8 (3-hour K indices: 1322 3221, Boulder K indices: 1323 3322). Region 9648 was quiet and stable. Region 9650 decayed quietly and could become spotless today. Region 9653 lost some of its area as the main penumbra is splitting into smaller penumbras. Some new spots emerged and the region could produce occasional minor M class flares. Region 9655 decayed slowly and quietly. Region 9657 was mostly quiet and stable. Region 9658 developed slowly and may be capable of minor M class flare production. New regions 9659 and 9660 emerged slowly in the northeast quadrant. New region 9661 rotated partly into view at the northeast limb. Magnetograms early today suggest that the region has mixed polarities with the best flare potential of the visible regions and could produce minor M class flares. Flares and CMEs A total of 6 C class events were recorded on October 10. Region 9658 produced a C3.4 flare at 08:22, a C1.7 flare at 09:20 and a C2.1 flare at 11:03 UTC. Region 9657 generated a C2.2 flare at 19:30 UTC. October 9: 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. 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 major storm on October 11 due to a likely CME impact during the latter half of the day. 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 region numbered sunspots at Area Classification Comment midnight 9642 2001.09.29 N05W79 plage 9646 2001.10.01 N13W80 plage 9647 2001.10.02 S18W73 plage 9648 2001.10.02 1 S07W34 0020 HSX 9650 2001.10.03 7 S15W21 0020 CRO 9652 2001.10.04 N21W65 plage 9653 2001.10.04 13 S21W02 0160 DAI 9654 2001.10.05 N07W58 plage 9655 2001.10.06 3 S21E12 0070 CAO 9656 2001.10.07 S21W54 plage 9657 2001.10.08 6 N23E44 0030 CSO 9658 2001.10.09 7 S14E55 0180 FAO 9659 2001.10.10 3 N04E19 0010 BXO 9660 2001.10.10 2 N12E20 0010 AXX 9661 2001.10.10 1 N12E76 0060 HAX beta-gamma? Total number of sunspots: 43 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) 2001.10 185.2 (1) 58.4 (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]