Solar Terrestrial Activity Report [Image] Last update December 12, 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 to unsettled on December 11. Solar wind speed ranged between 490 and 607 km/sec, generally decreasing all day. Solar flare activity was low. Solar flux was 143.6, the planetary A index was 7 (3-hour K indices: 3222 2222, Boulder K indices: 3222 2122). Region 9254 was quiet and stable, as was region 9258. Region 9262 was mostly quiet and stable, C class flares are possible. Region 9263 decayed into spotless plage. Regions 9264 and 9265 were quiet and stable. New region 9266 emerged in the northwest quadrant to the north of region 9258. New region 9267 emerged fairly quickly early in the day and is located southeast of region 9262 in the northeast quadrant. Flares and CMEs A total of 5 C class events were recorded on December 11. Region 9267 produced a C1.9 flare at 15:14 UTC, the remainder of the flares were optically uncorrelated. 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 possibly geoeffective position on December 12 or 13. Forecast The geomagnetic field is expected to be quiet to unsettled on December 12-13. 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 20001203 3 N10W45 0030 CAO 9255 20001203 N23W38 plage 9256 20001204 S17W28 plage 9257 20001206 N19W29 plage 9258 20001207 2 N14W04 0000 BXO 9259 20001207 S09W74 plage 9262 20001208 11 N14E31 0100 DAO 9263 20001209 N18E38 plage 9264 20001210 3 S23E54 0070 CSO 9265 20001210 1 N18E56 0020 HSX 9266 20001211 4 N24W11 0020 CAO 9267 20001211 7 N08E39 0070 DAI Total number of sunspots: 31 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) 2000.12 151.0 (1) 39.7 (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]