Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update February 13, 2000 at 06:10 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 severe storm level on February 12. Solar wind speed ranged between 484 and 629 km/sec. Solar flare activity was moderate. Solar flux was 163.2, the planetary A index was 52 (3-hour Kp indices: 5456 6542, Boulder K indices: 5567 5442). Region 8855 was quiet and stable and rotated off the visible disk early today. Region 8856 was quiet and mostly stable. Region 8858 was mostly unchanged and could produce occasional C class flares. Region 8862 was quiet and stable, as was region 8864. Region 8863 decayed into spotless plage. Region 8867 was quiet and stable. Region 8868 was mostly unchanged and could produce C flares. Region 8869 is developing slowly and could produce C flares. Region 8870 was quiet and stable, as were regions 8871 and 8872. Flares and CMEs 1 C flare and 1 M flare were recorded on February 12. Region 8858 was the source of a long duration M1.7/1N event peaking at 0410 UTC. A weak type II sweep and a strong type IV sweep were associated with the LDE. A full halo CME was observed in LASCO C2 images, however, the halo effect may be apparent as a large CME was moving off the northwest limb at almost the same time. February 11: Region 8856 was the source of a C2.3 flare at 12:34 UTC and an associated partial halo coronal mass ejection. This CME could impact Earth on February 14 or 15 and cause a few unsettled to active intervals. The background x-ray flux is at the class B5 level. Coronal holes A trans equatorial coronal hole was in a geoeffective position on February 10. A coronal hole in the northern hemisphere will rotate into a possibly geoeffective position on February 13-14 and could cause unsettled to active intervals on Feb.16-17. Forecast The geomagnetic field is expected to be quiet to active on Feb.13. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally very 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 S13W79 plage 8854 20000201 S34W57 plage 8855 20000202 1 N18W87 0000 AXX 8856 20000202 4 S14W48 0040 DSO 8858 20000203 7 N25W38 0040 DSO 8862 20000206 1 S06W06 0140 HSX 8863 20000208 S16E17 plage 8864 20000208 1 N44W67 0000 AXX 8865 20000208 S12W30 plage 8866 20000208 N15E12 plage 8867 20000209 9 S16W07 0020 BXO 8868 20000209 9 S24W07 0070 DSO 8869 20000210 5 S24E61 0050 CSO 8870 20000210 1 N20E51 0060 HSX 8871 20000211 5 S14W24 0030 CSO 8872 20000211 4 S27E65 0090 DAO Total number of sunspots: 47 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 2000.02 167.8 (1) 66.0 (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]