Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update December 16, 1999 at 04:05 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 15. Solar wind speed ranged between 353 and 451 km/sec. Solar flare activity was low. Solar flux was 178.7, the planetary A index was 4 (3-hour Kp indices: 0000 1113, Boulder K indices: 0000 0122). Region 8788 rotated off the visible disk. Region 8790 decayed into spotless plage. Region 8792 was quiet and stable, the region appears to be spotless early on Dec.16. Region 8793 reemerged with a single spot, but is spotless again early on Dec.16. Region 8794 developed slowly and was quiet. Region 8795 decayed into spotless plage. Region 8796 was quiet and stable and could become spotless within a couple of days. Region 8797 was quiet and stable but could produce occasional C class flares. Region 8798 developed further and has a fairly good chance of producing an M flare. Region 8799 was quiet and stable. It should be noted that the region shares the positive plage field with region 8798. Should that region expand further region 8799 will become a part of region 8798. Region 8800 was quiet and stable, the region could become spotless in a day or two. Region 8801 was quiet and stable, it appears to be spotless early on Dec.16. An active region at the northeast limb will be rotating into view today. Flares and CMEs 3 C flares were recorded on December 15 with region 8798 the source of 2 of those flare. The region produced a C2.5 flare at 14:17 UTC. The background x-ray flux is at the class C1 level. Coronal holes A weak coronal hole in the northern hemisphere could rotate into a geoeffective position on December 20. Forecast The geomagnetic field is expected to be quiet to unsettled on December 16-17. 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 8788 991202 1 N14W86 0080 HAX 8790 991206 N15W82 plage 8791 991207 S15W43 plage 8792 991208 3 N20W24 0010 BXO 8793 991209 1 S16W70 0000 AXX 8794 991209 6 S14W20 0020 BXO 8795 991210 S12W57 plage 8796 991213 1 S26W32 0000 AXX 8797 991213 10 S33W16 0090 DSO 8798 991213 14 S14E48 0280 DKC 8799 991213 7 S09E47 0050 DSO 8800 991214 1 N09E47 0000 AXX 8801 991214 4 S22W13 0010 BXO Total number of sunspots: 48 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 (92.5 predicted, +2.1) 9907 165.6 113.5 (94.0 predicted, +1.5) 9908 170.7 93.7 (98.9 predicted, +4.9) 9909 135.7 70.6 9910 164.8 116.4 9911 191.5 132.7 9912 158.1 (1) 54.8 (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]