Solar Terrestrial Activity Report [Image] Last update October 22, 2000 at 05:15 UTC. Minor update posted at 10:46 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 21. Solar wind speed ranged between 358 and 397 km/sec. Solar flare activity was moderate. Solar flux was 158.0, the planetary A index was 4 (3-hour K indices: 1001 2221, Boulder K indices: 1000 2321). Region 9198 decayed slightly but could produce C flares and perhaps even a minor M class flare. Region 9199 decayed and could produce occasional C class flares. Region 9200 developed slowly early in the day, then decayed quickly late in the day and early on October 22. Region 9201 developed slowly and is capable of producing further minor M class flares. Region 9202 decayed slowly and could become spotless in a couple of days. Region 9203 was quiet and stable, as was region 9204. New region 9205 emerged in the northwest quadrant, it appears to be spotless early on October 22. Comment added at 10:46 UTC on October 22: A coronal stream related disturbance began at approximately 08h UTC, initially the disturbance appears to be slightly stronger than I expected. There is a possibility for isolated minor storm intervals later today. Flares and CMEs A total of 5 C and 1 M class events were recorded on October 21. Region 9199 produced a C1.6 long duration event peaking at 05:26 and a C5.6 flare at 09:56 UTC. Region 9201 generated a C2.3 flare at 14:06 and an M3.0/1N flare at 18:31 UTC. Region 9203 was the source of a long duration C3.6 event peaking at 02:31 UTC, a CME may have been associated with this event and an update will be posted later today if there was a potentially geoeffective CME. The background x-ray flux is at the class B6 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 active on October 22-23 due to a weak coronal stream. 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 Location region numbered no. at Area Classification Comment sunspots midnight 9191 20001010 N18W75 plage 9194 20001012 S11W54 plage 9197 20001012 N25W49 plage 9198 20001014 11 S29W24 0120 DAO 9199 20001015 18 N10W17 0090 FAO 9200 20001016 12 S17W08 0010 BXO 9201 20001017 34 N16E19 0250 DAI beta-gamma-delta 9202 20001018 3 N07W10 0010 AXX 9203 20001020 2 N15W29 0020 HSX 9204 20001020 5 N10E01 0020 AXX 9205 20001021 1 N36W20 0010 HRX Total number of sunspots: 86 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) 2000.08 163.0 130.5 (125.0 predicted, +0.1) 2000.09 182.1 109.9 2000.10 163.6 (1) 96.8 (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]