Solar Terrestrial Activity Report [Image] Last update October 8, 2001 at 03:40 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 on October 7. Solar wind speed ranged between 337 and 400 km/sec. Solar flare activity was low. Solar flux was 172.7, the planetary A index was 4 (3-hour K indices: 0001 2222, Boulder K indices: 0002 1002). Region 9641 was quiet and stable, as was region 9642. Region 9645 decayed further and is rotating out of view at the southwest limb. Region 9648 was quiet and stable. Region 9650 did not change significantly and remains capable of producing occasional C flares. Region 9651 decayed and was spotless by noon. Region 9652 decayed and was spotless by early evening. Region 9653 was mostly unchanged and mostly quiet. Region 9655 was quiet and stable. New region 9656 emerged in the southwest quadrant but appears to be decaying and could become spotless today. New regions will be rotating into view at the northeast and southeast limbs today and tomorrow. Flares and CMEs A total of 7 C class events were observed on October 7. Region 9653 produced a C1.8 flare at 07:32 UTC. Region 9650 generated a C1.2 flare at 16:41, a C1.2 flare at 19:28 and yet another C1.2 flare at 22:58 UTC. 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 B7 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on October 7-8. 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 9640 2001.09.27 N11W66 plage 9641 2001.09.27 3 S13W61 0100 HAX 9642 2001.09.29 1 N04W40 0010 HSX 9644 2001.10.01 N20W81 plage 9645 2001.10.01 4 S18W81 0150 EAO 9646 2001.10.01 N13W41 plage 9647 2001.10.02 S18W34 plage 9648 2001.10.02 5 S07E08 0070 CAO 9650 2001.10.03 19 S14E18 0100 DAO 9651 2001.10.04 1 S25W55 0000 AXX now spotless 9652 2001.10.04 3 N21W26 0010 CRO now spotless 9653 2001.10.04 8 S22E37 0280 DKO 9654 2001.10.05 N07W19 plage 9655 2001.10.06 6 S21E52 0180 DAO 9656 2001.10.07 4 S21W13 0020 BXO Total number of sunspots: 54 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) 2001.10 189.4 (1) 46.7 (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]