Solar Terrestrial Activity Report [Image] Last update December 13, 2000 at 05:10 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 on December 12. Solar wind speed ranged between 416 and 567 km/sec. Solar flare activity was moderate. Solar flux was 149.8, the planetary A index was 5 (3-hour K indices: 1112 2221, Boulder K indices: 1112 2321). Region 9254 was quiet and stable. Region 9258 decayed into spotless plage. Region 9262 was mostly quiet and stable, C class flares are possible. Regions 9264, 9265 and 9266 were quiet and stable. Region 9267 developed further and could produce further minor M class flares. Magnetograms indicate that the region is becoming more complex. Several new spots have developed late on Dec.12 and early on Dec.13. Flares and CMEs A total of 4 C and 1 M class events were recorded on December 12. Region 9267 produced a C2.6 flare at 05:00 and an M1.3/1F flare at 15:07 UTC. The background x-ray flux is at the class B5 level. Coronal holes A small coronal hole in the northern hemisphere will rotate into a geoeffective position on December 13. Forecast The geomagnetic field is expected to be quiet to unsettled on December 13-15. A weak coronal stream could cause a few unsettled to active intervals on December 16. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 9254 2000.12.03 2 N09W58 0020 HSX 9255 2000.12.03 N23W51 plage 9256 2000.12.04 S17W41 plage 9257 2000.12.06 N19W42 plage 9258 2000.12.07 N14W17 plage 9259 2000.12.07 S09W87 plage 9262 2000.12.08 15 N14E18 0100 DAO 9263 2000.12.09 N18E25 plage 9264 2000.12.10 5 S24E42 0060 DAO 9265 2000.12.10 1 N20E43 0020 HSX 9266 2000.12.11 2 N23W24 0020 CSO 9267 2000.12.11 10 N08E25 0100 DAI beta-gamma Total number of sunspots: 35 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) 2000.12 150.9 (1) 42.8 (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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]