Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update December 15, 1999 at 04:25 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 on December 14. Solar wind speed ranged between 376 and 505 km/sec. The interplanetary magnetic field remained stronger than usual during most of the day but was generally weakly to moderately northwards resulting in very little geomagnetic activity. Solar flare activity was low. Solar flux was 168.4, the planetary A index was 3 (3-hour Kp indices: 1000 2111, Boulder K indices: 2111 0220). Region 8788 was quiet, the region will rotate off the visible disk late today. Region 8790 decayed further and was quiet, the region is spotless early on Dec.15. Region 8792 decayed slowly and was quiet. Region 8793 decayed into spotless plage. Regions 8794 and 8795 were quiet and stable. Region 8796 was quiet and stable. Region 8797 developed slowly and should be capable of C class flaring. Region 8798 is developing and could become capable of minor M class flaring today. Region 8799 was quiet and stable. New region 8800 rotated into view at the northeast limb. New region 8801 emerged in the southeast quadrant near the central meridian. Flares and CMEs 3 C flares were recorded on December 14 with region 8798 producing a C1.1 flare at 16:59 UTC. The background x-ray flux is at the class B7 level. Coronal holes A coronal hole in the northern hemisphere will rotate into a geoeffective position on December 20. Forecast The geomagnetic field is expected to be quiet to unsettled on December 15-16. 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 8788 991202 5 N11W75 0170 FAO 8790 991206 1 N15W69 0000 AXX 8791 991207 S15W30 plage 8792 991208 1 N16W11 0000 AXX 8793 991209 S17W59 plage 8794 991209 1 S13W08 0010 HSX 8795 991210 3 S14W47 0030 DRO 8796 991213 1 S27W18 0000 AXX 8797 991213 7 S34W02 0080 DAO 8798 991213 5 S13E60 0100 DAO 8799 991213 2 S09E60 0080 DAO 8800 991214 1 N11E60 0020 HRX 8801 991214 2 S23W01 0000 BXO Total number of sunspots: 29 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 156.6 (1) 50.1 (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]