Solar Terrestrial Activity Report [Image] Last update December 7, 2000 at 04:10 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 to unsettled on December 6. Solar wind speed ranged between 318 and 361 km/sec. A weak disturbance appears to have arrived at ACE at approximately 22:30 UTC. Solar flare activity was moderate. Solar flux was 141.0, the planetary A index was 4 (3-hour K indices: 0132 2322, Boulder K indices: 0132 2322). Region 9242 rotated off the visible disk. Region 9245 was quiet and stable, the region is spotless early on Dec.7. Region 9246 became much more unstable as an area of opposite polarity developed very near the leader spots. Further M class flares are possible before the region rotates out of view early on December 9. Region 9254 developed slowly. The positive and magnetic polarities are slowly drifting apart and the region could soon be decaying. Region 9255 was quiet and stable, as was region 9256. New region 9257 emerged in the northeast quadrant, one day's rotation to the east of region 9255. Flares and CMEs A total of 5 C and 1 M class events were recorded on December 6. Region 9246 produced a C2.7 flare at 17:55 and an M1.6 flare at 22:30 UTC. A halo CME was observed in LASCO C2 beginning at 17:50 UTC, this CME likely had a backside origin. The background x-ray flux is at the class B5 level. Coronal holes A large trans equatorial coronal hole will rotate into a geoeffective position on December 6-9 and cause unsettled to major storm conditions on December 9-12. Forecast The geomagnetic field is expected to be quiet to unsettled on December 7-8 with a possibility of isolated active intervals on Dec.7. Quiet to minor storm is expected on December 9 due to a coronal stream. 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 at region numbered sunspots midnight Area Classification Comment 9242 20001124 1 N20W94 0060 HSX 9245 20001128 2 N04W39 0010 AXX 9246 20001128 9 S11W62 0110 DAO 9247 20001129 N14W72 plage 9249 20001130 N12W35 plage 9251 20001203 S22W73 plage 9252 20001203 S02W75 plage 9253 20001203 S14W28 plage 9254 20001203 10 N10E23 0150 DAO 9255 20001203 1 N23E26 0010 HRX 9256 20001204 2 S17E37 0010 HSX 9257 20001206 4 N19E38 0010 HRX Total number of sunspots: 29 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) 2000.04 184.2 125.5 120.8 (+0.9) 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) 2000.12 159.0 (1) 25.6 (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]