Solar Terrestrial Activity Report [Image] Last update October 10, 2000 at 03:55 UTC. Warning! Possible major solar storm heading towards Earth! [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update October 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update October 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update October 2, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update August 10, 2000)] Recent development The geomagnetic field was quiet on October 9. Solar wind speed ranged between 316 and 337 km/sec. A weak coronal stream began influencing the geomagnetic field late in the day, the intensity of this disturbance has increased slowly over the last few hours. Solar flare activity was low. Solar flux was 140.8, the planetary A index was 5 (3-hour K indices: 1111 2222, Boulder K indices: 1011 1211). Region 9176 was quiet and stable and rotated over the west limb. Region 9178 was quiet and stable, the region is rotating off the visible disk. Region 9181 decayed slowly and was quiet. Region 9182 changed quite a bit during the day with an area of negative magnetic polarity forming ahead of the lead positive polarity spot. This caused the region to become unstable and there is a chance of an M class flare today. Region 9187 was quiet and stable, it is spotless early on October 10. Region 9188 was quiet and stable, no spots are observed early on October 10. Region 9189 developed slowly and was quiet. Region 9190 was quiet and stable. Flares and CMEs A total of 9 C class events were recorded on October 9. Region 9187 produced a C5.7/1N flare at 13:16, a C1.0 flare at 16:58 and a C6.7/1F long duration event which peaked at 23:43 UTC. The latter event was accompanied by a moderate type II sweep and a weak type IV sweep. The flare caused a filament (located to the east of the region and right at the center of the sun) to erupt as well. A fairly large full halo coronal mass ejection was observed in LASCO C3 images early on October 10. The CME could cause a major geomagnetic disturbance when it hits Earth, most likely on October 12, but possibly even as soon as late on October 11. The background x-ray flux is at the class B5 level. Coronal holes Isolated coronal holes in both the southern and northern hemisphere will rotate into geoeffective positions on October 14-16. Forecast The geomagnetic field is expected to be quiet to active on October 10 due to a coronal stream. A possibly major disturbance will begin on October 12 and cause active to severe storming. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair. 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 9176 20000927 1 S09W92 0120 DAO 9178 20000928 1 S20W86 0080 HSX 9181 20001002 6 S29W24 0060 DSO 9182 20001002 4 N02W18 0130 FSO beta-gamma 9184 20001003 S14W15 plage 9187 20001008 1 N21W22 0000 AXX 9188 20001008 3 S12E16 0000 BXO 9189 20001008 7 N14E44 0030 CRO 9190 20001008 3 S18E59 0110 DSO Total number of sunspots: 26 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.09 135.7 71.5 102.3 (+4.8) 1999.10 164.8 116.7 107.8 (+5.5) 1999.11 191.5 133.2 110.9 (+3.1) 1999.12 169.8 84.6 111.0 (+0.1) 2000.01 158.1 90.1 112.8 (+1.8) 2000.02 174.1 112.9 116.6 (+3.8) 2000.03 208.2 138.5 119.8 (+3.2) 2000.04 184.2 125.3 (121.7 predicted, +1.9) 2000.05 184.9 120.8 (122.5 predicted, +0.8) 2000.06 179.8 124.9 (124.1 predicted, +1.6) 2000.07 202.3 169.1 (126.2 predicted, +2.1) 2000.08 163.0 130.6 (124.8 predicted, -1.4) 2000.09 182.1 109.9 2000.10 173.1 (1) 43.8 (2) 1) Running average based on the daily 20:00 UTC solar flux value at 2800 MHz. 2) Unofficial, accumulated value. The official value 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 in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]