Solar Terrestrial Activity Report [Image] Last update November 27, 2000 at 01:35 UTC. Minor update posted at 20:13 UTC. A fatal hard disk problem was discovered during maintenance and the dxlc.com site had to be restored from a recent backup. Unfortunately a consequence was that the web site was unavailable much longer than expected. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update November 1, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update November 1, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update November 1, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update October 20, 2000)] Recent development The geomagnetic field was quiet to minor storm on November 26. Solar wind speed ranged between 358 and 672 km/sec. A minor solar wind shock was observed at 05:04 UTC at ACE, however, the interplanetary magnetic field was mostly northwards after the shock passage and caused only a minor increase in geomagnetic activity. A strong solar wind shock was observed at 11:31 UTC at ACE. Solar wind speed increased abruptly from 450 to 600 km/sec and the interplanetary magnetic field initially swung very strongly northwards. The IMF became gradually more southwards later on but has still not been strongly or very strongly southwards. The above 10 MeV proton event increased significantly in intensity as the second shock approached Earth and for some hours after the shock, a peak near 900 pfu has been observed. Solar flare activity was high. Solar flux was 202.4, the planetary A index was 22 (3-hour K indices: 1132 4455, Boulder K indices: 2232 3535). Region 9233 decayed into spotless plage. Region 9235 was quiet and stable and is rotating off the visible disk. Region 9236 was generally unchanged as a complex region with a strong magnetic delta configuration. Further X class flares are possible and likely. Region 9239 was quiet and stable. Region 9240 developed several new spots and is capable of producing a major flare. Region 9242 was quiet and stable. Comment added at 20:13 UTC on November 27: The geomagnetic field has been unsettled to major storm today. The interplanetary magnetic field has been northwards for the last several hours. Solar flare activity has been surprisingly low today. Region 9236 could still produce another X flare but appears slightly less complex now. A new region has developed very quickly to the east southeast of region 9236 and is already fairly complex with mixed polarities. Minor M class flares are possible. Another region has emerged in the southeast quadrant. Flares and CMEs A total of 4 C, 1 M and 1 X class events were recorded on November 26. Region 9236 produced an M2.2/1F flare at 03:08 (due to a data gap in LASCO images it is uncertain if there was a CME associated with this event), a C2.8 flare at 11:38, a C3.4 flare at 12:41, a C2.2 flare at 15:12 and its largest flare so far, a major X4.0/2B impulsive flare at 16:48 UTC. A full halo CME was observed in LASCO images and will impact Earth on November 28. November 25: Region 9240 produced a long duration major M8.2/2N event at 01:31 UTC. This event was accompanied by a strong type II sweep and a moderate long lasting type IV sweep. A CME may have been produced as well and could impact Earth on November 27. Region 9236 generated an M3.5/2N flare at 09:20 (associated with another full halo CME) and a major impulsive X1.9/2B flare at 18:44 UTC. A strong type II sweep was recorded and a full halo CME was observed in LASCO images. November 24: Region 9236 produced a major impulsive X2.0/3B flare at 05:01 (associated with a strong type II sweep and a fast full halo CME), a major impulsive X2.3/2B flare at 15:13 (associated with a strong type II sweep and another full halo CME) and finally another major flare, an X1.8/2N event at 21:59 UTC. Region 9236 was near the central meridian and all the CMEs are likely to be heading almost directly towards Earth. The background x-ray flux is at the class B9 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be active to severe storm on November 27-28. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor to useless. 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 9233 20001114 N15W83 plage 9235 20001116 1 N10W83 0050 HAX 9236 20001118 22 N24W38 0600 EKI gamma-delta 9238 20001120 S22W74 plage 9239 20001121 3 S21E10 0150 CSO 9240 20001122 15 N08E22 0300 DHO beta-gamma 9241 20001123 N21W59 plage 9242 20001124 4 N19E39 0020 BXO Total number of sunspots: 45 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 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) 2000.04 184.2 125.3 120.7 (+0.9) 2000.05 184.9 120.8 (119.6 predicted, -1.1) 2000.06 179.8 124.9 (120.3 predicted, +0.7) 2000.07 202.3 169.1 (122.4 predicted, +2.1) 2000.08 163.0 130.5 (122.5 predicted, +0.1) 2000.09 182.1 109.9 (121.0 predicted, -1.5) 2000.10 167.4 100.1 (119.8 predicted, -1.2) 2000.11 176.7 (1) 129.0 (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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]