Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update December 9, 1999 at 03:40 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 8 under the influence of a high speed coronal stream. Solar wind speed ranged between 491 and 598 km/sec, slowly decreasing all day. Solar flare activity was low. Solar flux was 150.1, the planetary A index was 13 (3-hour Kp indices: 3243 2333, Boulder K indices: 3333 2332). Region 8785 was quiet and stable. Region 8787 decayed slowly is spotless early on Dec.9. Region 8788 was mostly quiet. The region has minor M class flaring potential. Region 8790 was mostly quiet and stable. The region is developing slowly early on Dec.9. Region 8791 was quiet and stable. New region 8792 rotated into view at the northeast limb. An active region is rotating into view at the southeast limb, this region appears to have M class flaring potential. Flares and CMEs 6 C flares were recorded on December 8, none of them of particular interest. December 6: Region 8788 produced a C8.4 flare at 07:18 UTC. It was accompanied by a type II sweep and a full halo coronal mass ejection. This CME has a high probability of impacting Earth sometime on December 9 or early on Dec.10. The background x-ray flux is at the class B5 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on December 9. If the CME observed on Dec.6 impacts Earth today, unsettled to major storm would be likely. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally 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 8784 991130 N30W73 plage 8785 991201 5 N14W21 0150 CSO 8787 991202 1 N12W32 0000 AXX 8788 991202 17 N11E04 0590 FKO 8789 991202 N29W87 8790 991206 6 N11E20 0020 CRO 8791 991207 3 S14E53 0010 BXO 8792 991208 1 N17E68 0090 HAX Total number of sunspots: 33 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 152.3 (1) 25.4 (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]