Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update February 11, 2000 at 03:10 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 unsettled on February 10. Solar wind speed ranged between 403 and 530 km/sec. A solar wind shock was observed at 02:20 UTC at ACE. Solar wind speed increased abruptly from 420 to 550 km/sec. This was likely the arrival of the CME observed on February 8. Solar flare activity was low. Solar flux was 175.7, the planetary A index was 7 (3-hour Kp indices: 2221 2223, Boulder K indices: 2232 2323). Region 8854 was quiet and stable. Region 8855 decayed and could become spotless today. Region 8856 was quiet and stable. Region 8857 decayed into spotless plage. Region 8858 decayed further and is unlikely to produce other than occasional C or minor M class flares. Region 8861 was quiet and stable and will rotate over the west limb today. Region 8862 was quiet and stable. Region 8863 decayed and could become spotless today. Region 8864 reemerged with a few spots. Region 8866 decayed into spotless plage. Region 8867 was quiet and stable. Region 8868 was unstable early in the day, further C class flares are possible. New region 8869 rotated partly into view at the southeast limb. New region 8870 rotated partly into view at the northeast limb. Flares and CMEs 5 C flares were recorded on February 10. Region 8868 produced a C2.7 flare at 00:28 UTC and a C2.3 flare at 01:04 UTC. Region 8858 was the source of an interesting C7.3/1N long duration event peaking at 02:08 UTC. A moderately strong type II sweep with an estimated shock speed of 1000 km/sec associated with a fast full halo coronal mass ejection was observed as well. This event occurred very near the central meridian and the CME will impact Earth, probably on February 12. Minor to severe storming is possible, however, as there are 3 CMEs currently heading towards Earth, the solar wind pattern will likely be very complex, particularly on February 12. February 9: A large filament eruption in spotless region 8853 was the most impressive event of the day, a C7.4/2F long duration event peaking at 20:06 UTC. This resulted in a wide and full halo coronal mass ejection which is likely to impact Earth on February 12 or 13 (unless it is overtaken by the faster CME mentioned above, the result could be a complex solar wind pattern). 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 B9 level. Coronal holes An emerging trans equatorial coronal hole was in a geoeffective position on February 10. The resulting coronal stream is not likely to be observed at Earth due to the effects from the above mentioned CMEs. A coronal hole in the northern hemisphere will rotate into a possible geoeffective position on February 13 and could cause unsettled to active intervals on Feb.16-17. Forecast The geomagnetic field is expected to be unsettled to minor storm on February 11 with possible major storm intervals. Minor to severe storming is possible on February 12-13 due to CME effects. 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 8853 20000201 S13W53 plage 8854 20000201 4 S34W31 0020 CRO 8855 20000202 1 N17W55 0000 AXX 8856 20000202 7 S13W19 0060 DSO 8857 20000203 S17W84 plage 8858 20000203 12 N27W10 0050 DSO 8860 20000204 N30W72 plage 8861 20000205 7 N08W78 0320 DAO 8862 20000206 1 S06E21 0140 HSX 8863 20000208 1 S15E44 0000 AXX 8864 20000208 3 N44W38 0020 BXO 8865 20000208 S12W04 plage 8866 20000208 N15E38 plage 8867 20000209 3 S15E19 0000 BXO 8868 20000209 11 S23E21 0040 CSO 8869 20000210 1 S25E70 0020 HAX 8870 20000210 1 N20E77 0060 HSX Total number of sunspots: 52 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 2000.02 168.0 (1) 54.2 (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]