Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update February 10, 2000 at 03:30 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update February 3, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update February 3, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update February 3, 2000)] [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 February 9. Solar wind speed ranged between 410 and 527 km/sec. Solar flare activity was low. Solar flux was 199.0 (influenced by a flare in progress, a better value would be 180, the average of the 17 and 23 UTC measurements), the planetary A index was 11 (3-hour Kp indices: 1321 4432, Boulder K indices: 1331 3412). Region 8851 was quiet and stable, the region rotated over the west limb early today. Region 8853 decayed into spotless plage but did manage to produce an interesting long duration event. Regions 8854 and 8855 were quiet and stable. Region 8856 decayed slowly and was quiet. Region 8857 decayed slowly and was quiet. Region 8858 became less complex and is unlikely to produce other than occasional C or minor M class flares. Region 8861 developed further and is capable of minor M class flaring, the region will rotate off the visible disk on Feb.11. Regions 8862 and 8863 were quiet and stable. Regions 8864 and 8865 decayed into spotless plage. Region 8866 was quiet and stable. New regions 8867 and 8868 emerged in the southeast quadrant. An active region is rotating into view at the southeast limb and could be capable of minor M class flaring. Flares and CMEs 7 C flares were recorded on February 9. Region 8858 generated a long duration C6.6 event peaking at 00:51 UTC. Region 8861 produced a C1.2 flare at 02:19 UTC and a C1.7 flare at 15:52 UTC. Region 8853 was the source of the most impressive event of the day, a C7.4/2F long duration event peaking at 20:06 UTC. A partial halo coronal mass ejection covering all of the southern hemisphere and most of the west limb was observed in LASCO C2 at 20:06 UTC. This CME could impact Earth late on February 12 or sometime on Feb.13. A C7.3 long duration event peaked at 02:08 UTC on February 10. The source of the flare was region 8858. A type II sweep with an estimated shock speed of 1000 km/sec was observed as well. The associated coronal mass ejection could be geoeffective. February 8: Region 8858 was the source of an M1.3/1B long duration event peaking at 09:00 UTC. A strong type II sweep and a large full halo coronal mass ejection was associated with the event. The CME will likely impact Earth on February 11 or early on February 12 and cause unsettled to minor storm conditions. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on February 10. A CME could impact Earth late in the day or on the 11th causing unsettled to minor storm conditions. 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 8851 20000130 2 N24W85 0010 BXO 8853 20000201 S13W40 plage 8854 20000201 4 S34W15 0010 BXO 8855 20000202 4 N18W39 0010 BXO 8856 20000202 8 S14W07 0070 DSO 8857 20000203 3 S17W71 0010 BXO 8858 20000203 16 N27E01 0070 CAO 8860 20000204 N30W59 plage 8861 20000205 16 N07W68 0350 DAO 8862 20000206 2 S06E35 0140 HSX 8863 20000208 2 S14E57 0040 HSX 8864 20000208 N44W29 plage 8865 20000208 S12E09 plage 8866 20000208 1 N15E51 0000 AXX 8867 20000209 4 S14E32 0010 BXO 8868 20000209 7 S24E33 0020 CRO Total number of sunspots: 69 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.01 140.6 62.0 82.6 (+4.7) 1999.02 141.9 66.3 84.6 (+2.0) 1999.03 126.3 68.8 83.8 (-0.8) 1999.04 117.2 63.7 85.4 (+1.6) 1999.05 148.4 106.4 90.4 (+5.0) 1999.06 169.8 137.7 93.0 (+2.6) 1999.07 165.6 113.5 94.4 (+1.4) 1999.08 170.7 93.7 (97.4 predicted, +3.0) 1999.09 135.7 70.9 (102.4 predicted, +5.0) 1999.10 164.8 116.4 (107.5 predicted, +5.1) 1999.11 191.5 132.7 1999.12 169.8 86.4 2000.01 158.1 90.2 2000.02 167.1 (1) 48.3 (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]