Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update December 5, 1999 at 02:55 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 unsettled to major storm on December 4 under the influence of a high speed coronal stream. Solar wind speed ranged between 501 and 742 km/sec. Solar flare activity was low. Solar flux was 147.5, the planetary A index was 28 (3-hour Kp indices: 4346 5433, Boulder K indices: 3246 4432). Region 8781 decayed slowly and was quiet. Region 8782 rotated off the visible disk. Region 8785 was quiet and stable. Region 8786 decayed into spotless plage. Region 8787 was quiet and stable. Region 8788 rotated fully into view and is capable of minor M class flaring. Region 8789 decayed into spotless plage. Active regions at the southeast and northeast limbs will rotate onto the visible disk over the next 1-3 days. Flares and CMEs 3 C flares were recorded on December 4. The only flare of significance was a C4.3/1F event from region 8788 at 21:27 UTC. The background x-ray flux is at the class B5 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 unsettled to minor storm December 5-8, isolated major storm intervals are possible. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally 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 8780 991124 S15W78 plage 8781 991124 4 S12W58 0160 HSX 8782 991127 1 N11W92 0120 HAX 8784 991130 N30W21 plage 8785 991201 2 N13E30 0120 HSX 8786 991202 N22W39 plage 8787 991202 2 N12E18 0010 BXO 8788 991202 19 N10E56 0510 FKI beta-gamma 8789 991202 N29W36 plage 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 157.5 (1) 14.8 (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]