Solar Terrestrial Activity Report [Image] Last update October 28, 2000 at 06:00 UTC. Minor update posted at 09:38 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 27. Solar wind speed ranged between 325 and 372 km/sec. Solar flare activity was moderate. Solar flux was 175.9, the planetary A index was 5 (3-hour K indices: 2022 2211, Boulder K indices: 2021 2211). Region 9201 decayed further and was quiet. Region 9206 was quiet and stable. Region 9207 decayed slowly and was quiet. Region 9208 decayed losing all but one spot. Region 9209 developed slowly and could produce M class flares. Region 9210 was quiet and stable. New region 9211 emerged in the northwest quadrant, the region is spotless early on October 28. Two regions are rotating into view at the northeast limb near the equator, both could be capable of M class flare production. Comment added at 09:38 UTC on October 28: A moderate solar wind shock was observed at ACE at 09:04 UTC and will impact Earth in a few minutes time. The interplanetary magnetic field has swung moderately to strongly southwards and this will cause active to minor or major storming to occur, probably for the remainder of the day. Flares and CMEs A total of 7 C and 1 M class events were recorded on October 27. Region 9203, just behind the northwest limb, produced a C8.2 flare at 11:27 and a C9.7 flare at 12:03 UTC. An M1.1 flare at 20:56 was optically uncorrelated but may have had its origin in region 9203 or in one of the regions currently rotating onto the disk at the northeast limb. A filament eruption was observed in the northwest quadrant, there is a slight chance a CME could impact Earth on October 30. (Unfortunately no new LASCO C2 or C3 images have become available since late on October 26.) October 25: A very long duration C4.0 event began at 08:45, peaked at 11:25 and ended at 15:21 UTC. The source of this event was a large filament eruption between regions 9201 and 9199 in the northwest quadrant, with the major part of the eruption being near region 9199 at the northwest limb. A full halo CME was observed in LASCO images, the CME will impact Earth, most likely on October 28. The background x-ray flux is at the class C1 level. Coronal holes A small well placed coronal hole in the southern hemisphere was in a geoeffective position on October 26. Forecast The geomagnetic field is expected to be quiet to major storm on October 28. A coronal stream could cause unsettled to active conditions on October 29. 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 9200 20001016 S13W84 plage 9201 20001017 2 N19W65 0030 HSX 9202 20001018 N13W89 plage 9204 20001020 N10W77 plage 9206 20001023 7 N22E03 0020 CSO 9207 20001023 9 S19E14 0040 CSO 9208 20001023 1 S10E24 0040 HSX 9209 20001025 16 S24E48 0240 DAI beta-gamma 9210 20001026 6 S30E59 0110 DSO 9211 20001027 2 N30W43 0000 AXX Total number of sunspots: 43 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 2000.10 164.2 (1) 119.3 (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]