Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update December 12, 1999 at 03:50 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 unsettled on December 11. Solar wind speed ranged between 411 and 493 km/sec. A minor disturbance in the solar wind was observed 12-14h UTC at ACE as the interplanetary magnetic field swung moderately strongly southwards. This resulted in some magnetometers recording active conditions 13-15h UTC. Solar flare activity was low. Solar flux was 159.1, the planetary A index was 7 (3-hour Kp indices: 1232 3211, Boulder K indices: 1222 4310). Region 8785 was quiet and stable. Region 8787 was quiet and stable. The region will be rotating off the visible disk tomorrow, anyway, it is spotless early on Dec.12. Region 8788 was quiet and stable. Region 8790 appears to have peaked in its development and has begun a slow decay process. Region 8791 decayed into spotless plage. Region 8792 was quiet and stable, as was region 8793. Region 8794 was mostly quiet and stable. Region 8795 was mostly quiet and stable. An active region will rotate into view at the southeast limb in 1-2 days. Flares and CMEs 3 C flares were recorded on December 11. Region 8790 produced a C2.8/1F event at 03:33 UTC while region 8794 managed a C1.1 flare at 07:39 UTC. The background x-ray flux is at the class B5 level. Coronal holes A trans equatorial coronal hole was in a geoeffective position on December 10-11.. Forecast The geomagnetic field is expected to be quiet to unsettled on December 12. Unsettled to active is possible on December 13-14 due to a coronal stream. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally 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 8785 991201 1 N16W62 0090 HAX 8787 991202 2 N17W72 0000 BXO 8788 991202 14 N12W37 0440 FHO 8790 991206 16 N13W20 0040 CRO 8791 991207 S15E09 plage 8792 991208 4 N16E30 0080 CAO 8793 991209 5 S16W17 0010 BXO 8794 991209 2 S15E31 0030 CSO 8795 991210 10 S12W08 0060 DAO Total number of sunspots: 54 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 (93.6 predicted, +3.2) 9907 165.6 113.5 (96.9 predicted, +3.3) 9908 170.7 93.7 (102.8 predicted, +5.9) 9909 135.7 70.6 9910 164.8 116.4 9911 191.5 132.7 9912 154.4 (1) 37.7 (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]