Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update December 4, 1999 at 04:15 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 3. Solar wind speed ranged between 390 and 593 km/sec. The coronal stream that began influencing Earth in the evening of December 2 intensified. The solar wind was influenced by another source, perhaps a coronal mass ejection, from 10h UTC, and the interplanetary magnetic field has strengthened to a level not usually associated with a coronal stream. Solar flare activity was low. Solar flux was 151.8, the planetary A index was 13 (3-hour Kp indices: 3223 3432, Boulder K indices: 3323 4332). Region 8781 decayed slowly and was quiet. Region 8782 was mostly unchanged and will rotate off the visible disk today. Regions 8783 and 8784 decayed into spotless plage. Region 8785 was quiet and stable. Region 8786 was quiet and stable, as was region 8787. Region 8788 is the most complex region on the disk and could be capable of minor M class flaring. Region 8789 was quiet and stable. Flares and CMEs 4 C flares were recorded on December 3. The most energetic flare was a C6.3 event at 19:53 UTC, it was not optically assigned to any of the visible regions. The background x-ray flux is at the class B7 level. Coronal holes A large trans equatorial coronal hole was in a geoeffective position on December 1-6. Forecast The geomagnetic field is expected to be unsettled to minor storm December 4-9, 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 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 S15W65 8781 991124 13 S12W42 0190 DAO 8782 991127 15 N10W83 0310 FAI 8783 991130 S16W85 plage 8784 991130 N30W08 plage 8785 991201 2 N13E43 0100 HSX 8786 991202 2 N22W23 0000 BXO 8787 991202 1 N11E30 0000 AXX 8788 991202 1 N10E66 0270 HKX 8789 991202 3 N29W23 0010 BXO Total number of sunspots: 37 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 160.8 (1) 12.3 (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]