Solar Terrestrial Activity Report [Image] Last update February 11, 2001 at 07:10 UT. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update February 2, 2001) - Cycle 23 peaked in April 2000?] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update February 2, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update February 2, 2001)] [Historical solar and geomagnetic data charts 1954-2000 (last update January 18, 2001)] Recent development The geomagnetic field was quiet to unsettled on February 8. Solar wind speed ranged between 382 and 455 km/sec. Solar flare activity was low. Solar flux was 160.7, the planetary A index was 5 (3-hour K indices: 1212 2321, Boulder K indices: 1222 2311). Region 9330 lost all but one spot and will rotate over the west limb today. Region 9334 decayed slowly and was quiet. Region 9335 decayed and was quiet. Region 9338 developed further and could produce M class flares. Region 9339 decayed fairly quickly and was quiet. Region 9341 was quiet and stable. Region 9344 was quiet and stable, the region is spotless early on February 11. Region 9345 was quiet and stable, as was region 9347. New region 9348 emerged in the northeast quadrant near the central meridian. New region 9349 rotated into view at the northeast limb. A new region is rotating into view at the northeast limb. Flares and CMEs A total of 5 C class events were recorded on February 10. Region 9338 produced a C1.5 flare at 02:53 and a C1.9 flare at 20:10 UT. A filament eruption occurred sometime between 04:12 and 08 UT. LASCO-EIT images indicate that the eruption was fairly extensive and occurred in the northwest quadrant near the central meridian. LASCO C2 images indicate a full halo CME was in progress by 08 UT. With some uncertainty due to missing images it appears likely that the filament eruption caused a full halo CME which could impact Earth's magnetosphere sometime between late on Feb.12 and noon on Feb.13. An interesting C6.5 long duration event peaked at 01:23 UT on February 11. Its source was near the northwest limb but not inside any of the numbered regions. A fast partial halo CME was observed soon after the flare and could perhaps influence the geomagnetic field on February 13 or 14. The background x-ray flux is at the class B6 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 11-12. Unsettled to minor storming is possible on February 13-14. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair. 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 9330 2001.01.30 1 N22W80 0020 HSX 9334 2001.02.01 9 N12W42 0050 EAO 9335 2001.02.03 2 N11W29 0030 HSX 9337 2001.02.03 S28W14 plage 9338 2001.02.04 24 S20W15 0170 DAO beta-gamma 9339 2001.02.04 6 S10W08 0130 EAO 9340 2001.02.05 S11W62 plage 9341 2001.02.06 3 S10W30 0010 CSO 9342 2001.02.06 S26E03 plage 9343 2001.02.07 N03W31 plage 9344 2001.02.08 2 N30W14 0010 CSO 9345 2001.02.08 7 S20W07 0030 DAO 9346 2001.02.09 N18W67 plage 9347 2001.02.09 4 N03E51 0040 CSO 9348 2001.02.10 3 N09E05 0010 CRO 9349 2001.02.10 1 N28E60 0050 HSX Total number of sunspots: 62 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.11 191.5 133.2 111.0 (+3.2) 1999.12 169.8 84.6 111.1 (+0.1) 2000.01 158.1 90.1 112.9 (+1.8) 2000.02 174.1 112.9 116.8 (+3.9) 2000.03 208.2 138.5 119.9 (+3.1) 120.8 (+0.9) 2000.04 184.2 125.5 cycle 23 peak candidate 2000.05 184.9 121.6 119.0 (-1.8) 2000.06 179.8 124.9 118.7 (-0.3) 2000.07 202.3 170.1 119.8 (+1.1) 2000.08 163.0 130.5 (119.7 predicted, -0.1) 2000.09 182.1 109.7 (118.4 predicted, -1.3) 2000.10 167.4 100.1 (116.7 predicted, -1.7) 2000.11 178.8 106.5 (114.8 predicted, -1.9) 2000.12 173.6 104.5 (112.2 predicted, -2.6) 2001.01 166.6 95.7 (108.7 predicted, -3.5) 2001.02 161.8 (1) 55.8 (2) 1) Running average based on the daily 20:00 UTC solar flux value at 2800 MHz. 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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]