Solar Terrestrial Activity Report [Image] Last update October 21, 2000 at 02:40 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 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 October 20, 2000)] Recent development The geomagnetic field was quiet on October 20. Solar wind speed ranged between 378 and 460 km/sec. Solar flare activity was low. Solar flux was 160.7, the planetary A index was 4 (3-hour K indices: 1101 2212, Boulder K indices: 0111 1101). Region 9190 decayed into spotless plage, as did region 9194. Region 9198 developed and could produce C flares and perhaps even a minor M class flare. Region 9199 developed slowly and could produce C class flares, there is a slight possibility for a minor M class flare as well. Region 9200 decayed slowly and was quiet. Region 9201 developed slowly and is capable of minor M class flare production. Region 9202 was quiet and stable. New region 9203 emerged in the northwest quadrant near region 9199. New region 9204 emerged in the northeast quadrant just east of region 9202. Flares and CMEs A total of 4 C class events were recorded on October 20. Region 9199 produced a C1.1 flare at 01:00, a C1.2 flare at 14:00 and a C1.0 flare at 18:13 UTC. The background x-ray flux is at the class B5 level. Coronal holes A weak coronal hole stretching from the equator well into the southern hemisphere was in a geoeffective position on October 19. Forecast The geomagnetic field is expected to be quiet to unsettled on October 21. A weak coronal stream related disturbance could start on October 22. 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 9190 20001008 S14W86 plage 9191 20001010 N18W62 plage 9194 20001012 S11W41 plage 9197 20001012 N25W36 plage 9198 20001014 11 S30W11 0150 DAO 9199 20001015 21 N08W04 0140 ESI beta-gamma 9200 20001016 7 S16E08 0040 BXO 9201 20001017 22 N17E32 0220 DKI beta-gamma 9202 20001018 5 N11E05 0030 AXX 9203 20001020 4 N15W15 0030 CSO 9204 20001020 4 N09E15 0020 AXX Total number of sunspots: 74 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 (121.0 predicted, +1.2) 2000.05 184.9 120.8 (121.3 predicted, +0.3) 2000.06 179.8 124.9 (122.8 predicted, +1.5) 2000.07 202.3 169.1 (124.9 predicted, +2.1) 2000.08 163.0 130.6 (125.0 predicted, +0.1) 2000.09 182.1 109.9 2000.10 163.9 (1) 91.4 (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]