Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update December 6, 1999 at 01:45 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, 1999)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update December 2, 1999)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update December 2, 1999)] [Historical solar and geomagnetic data charts 1954-1999] [Experimental solar data chart January 1998-September 1999] Recent development The geomagnetic field was quiet to active on December 5 under the influence of a high speed coronal stream. Solar wind speed ranged between 602 and 734 km/sec, generally slowly decreasing. Solar flare activity was low. Solar flux was 142.7, the planetary A index was 18 (3-hour Kp indices: 4444 3332, Boulder K indices: 4454 3332). Region 8781 was quiet and stable, the region will rotate off the visible disk on Dec.7. Region 8785 developed slowly and was quiet. Region 8787 was quiet and stable. Region 8788 will likely continue to produce occasional C flares. There is only a minor chance of an M flare as the positive and negative polarities are well separated. Region 8789 reemerged with a few spots. Active regions at the southeast and northeast limbs will rotate onto the visible disk over the next days, none of them appear to be very active at this time. Flares and CMEs 4 C flares were recorded on December 5, the most energetic was an optically unaccounted C3.3 long duration event at 22:21 UTC. The background x-ray flux is at the class B4 level. Coronal holes A large trans equatorial coronal hole was in a geoeffective position on December 1-5. Forecast The geomagnetic field is expected to be quiet to minor storm December 5-8. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally poor to very 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 8781 991124 4 S13W71 0140 CAO 8784 991130 N30W34 plage 8785 991201 6 N13E18 0130 CSO 8786 991202 N22W52 plage 8787 991202 2 N12E03 0000 BXO 8788 991202 13 N10E43 0510 FKO 8789 991202 3 N29W48 0000 BXO Total number of sunspots: 28 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 9810 117.2 55.5 70.5 (+1.0) 9811 140.1 74.0 73.0 (+2.5) 9812 150.1 81.9 77.9 (+4.9) 9901 140.6 62.0 82.6 (+4.7) 9902 141.9 66.3 84.6 (+2.0) 9903 126.3 68.8 83.8 (-0.8) 9904 117.2 63.7 85.4 (+1.6) 9905 148.4 106.4 90.4 (+5.0) 9906 169.8 137.7 (94.4 predicted, +4.0) 9907 165.6 113.5 (99.4 predicted, +5.0) 9908 170.7 93.7 (105.3 predicted, +5.9) 9909 135.7 70.6 9910 164.8 116.4 9911 191.5 132.7 9912 154.5 (1) 17.4 (2) 1) Running average based on the daily 20:00 UTC solar flux measurement at 2800 MHz by DRAO. 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 in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]