Solar Terrestrial Activity Report [Image] Last update December 25, 2000 at 05:15 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update December 2, 2000) - Has cycle 23 peaked?] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update December 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update December 2, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update October 20, 2000)] Recent development The geomagnetic field was quiet on December 24. Solar wind speed ranged between 301 and 350 km/sec. The interplanetary magnetic field strengthened gradually from 16h UTC towards the end of the day. With a couple of exceptions, the IMF was almost fully northwards, and caused no significant change in geomagnetic activity levels. Should the IMF swing southward today we could see unsettled to active conditions. Solar flare activity was moderate. Solar flux was 193.0, the planetary A index was 20 (3-hour K indices: 1211 2222, Boulder K indices: 2211 1113). Region 9268 was quiet and stable. Region 9269 reemerged with a single spot and will rotate off the visible disk today. Region 9278 decayed slowly and was quiet. Region 9279 decayed and was quiet. Region 9280 developed slowly and could produce a major flare, however, the region has been fairly quiet over the last few days. Region 9281 decayed into spotless plage. Region 9282 was quiet and stable. Region 9283 developed slowly and has a magnetic delta configuration. A major flare is possible. Region 9284 was quiet and stable, the region appears to be spotless early on Dec.25. New region 9285 emerged near the northeast limb. New region 9286 emerged in the northwest quadrant. Flares and CMEs A total of 9 C and 1 M class events were recorded on December 24. Region 9283 produced a C2.0 flare at 00:11, a C7.0 flare at 01:08, a C6.6 flare at 06:53, an M1.1 flare at 11:15 and a C9.4 flare at 13:38 UTC. Region 9285 generated a C2.0 flare at 05:21 UTC. The background x-ray flux is at the class B8 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on December 25-26. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair to poor. 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 region numbered sunspots at Area Classification Comment midnight 9268 2000.12.13 1 S18W70 0080 HSX 9269 2000.12.13 1 N12W80 0000 AXX 9273 2000.12.15 N20W46 plage 9278 2000.12.17 5 N10W31 0040 CSO 9279 2000.12.18 2 S10W21 0060 HSX 9280 2000.12.19 29 N09E10 0560 EKI beta-gamma 9281 2000.12.20 N07W14 plage 9282 2000.12.21 1 N20E30 0040 HSX 9283 2000.12.22 8 S12E53 0200 DAI gamma-delta 9284 2000.12.23 4 N06W20 0020 CSO 9285 2000.12.24 2 N06E59 0050 CRO 9286 2000.12.24 2 N30W47 0030 CRO Total number of sunspots: 55 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.11 191.5 133.2 111.0 (+3.2) 1999.12 169.8 84.6 111.1 (+0.1) 2000.01 158.1 90.1 112.9 (+1.8) 2000.02 174.1 112.9 116.7 (+3.8) 2000.03 208.2 138.5 119.9 (+3.2) 120.8 (+0.9) 2000.04 184.2 125.5 cycle 23 peak candidate 2000.05 184.9 121.6 119.0 (-1.8) 2000.06 179.8 124.9 (118.3 predicted, -0.7) 2000.07 202.3 169.1 (119.8 predicted, +1.5) 2000.08 163.0 130.5 (120.5 predicted, +0.7) 2000.09 182.1 109.9 (119.6 predicted, -0.9) 2000.10 167.4 100.1 (118.4 predicted, -1.2) 2000.11 178.8 106.5 (116.4 predicted, -2.0) 2000.12 170.8 (1) 109.3 (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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]