Solar Terrestrial Activity Report [Image] Last update October 9, 2001 at 04:15 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 8. Solar wind speed ranged between 328 and 446 km/sec. What may have been a weak solar wind shock was observed at SOHO at 12:10 UTC with an abrupt increase in wind speed from 360 to 390 km/sec. Solar wind densities has been somewhat higher than average since then, however, the disturbance could be a mix of a weak CME and a weak coronal stream. Solar flare activity was low. Solar flux was 171.2, the planetary A index was 15 (3-hour K indices: 2333 4424, Boulder K indices: 2233 3424). Region 9641 decayed slowly and will rotate off the visible disk late today. Region 9642 decayed and appears to be spotless early on October 9. Region 9645 rotated over the southwest limb early in the day. Region 9648 decayed slowly and quietly. Region 9650 decayed quietly. Regions 9653 and 9655 decayed slowly and quietly. Region 9656 decayed and was spotless by early evening. New region 9657 rotated into view at the northeast limb. An active region is rotating into view at the southeast limb. Flares and CMEs A total of 4 C class events were recorded on October 8, none of them were optically correlated. 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 B7 level. Coronal holes A coronal hole in the northern hemisphere will rotate into a geoeffective position on October 9-10. Forecast The geomagnetic field is expected to be quiet to active on October 9-10. 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 9640 2001.09.27 N11W79 plage 9641 2001.09.27 1 S13W76 0050 HAX 9642 2001.09.29 1 N05W53 0010 AXX now spotless 9645 2001.10.01 2 S19W90 0060 HAX 9646 2001.10.01 N13W54 plage 9647 2001.10.02 S18W47 plage 9648 2001.10.02 4 S07W06 0030 CSO 9650 2001.10.03 17 S14E04 0060 DSO 9651 2001.10.04 S25W68 plage 9652 2001.10.04 N21W39 plage 9653 2001.10.04 6 S22E24 0220 DKC 9654 2001.10.05 N07W32 plage 9655 2001.10.06 6 S21E38 0130 DAO 9656 2001.10.07 2 S21W28 0010 BXO now spotless 9657 2001.10.08 1 N23E70 0040 HSX Total number of sunspots: 40 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) 2001.10 187.1 (1) 50.9 (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]