Solar Terrestrial Activity Report [Image] Last update February 12, 2001 at 04:00 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 11. Solar wind speed ranged between 380 and 436 km/sec. Solar flare activity was low. Solar flux was 151.3, the planetary A index was 7 (3-hour K indices: 2233 2211, Boulder K indices: 2243 2311). Region 9330 was quiet and rotated off the visible disk. Region 9334 decayed further and was quiet, the region could become spotless by the end of the day or tomorrow. Region 9335 decayed and was quiet, no spots are visible early on Feb.12. Region 9338 has decayed significantly over the last day but could still produce an isolated minor M class flare. Region 9339 was quiet and stable. Region 9341 was quiet and stable, the region is spotless early on Feb.12. Region 9345 decayed, was quiet and could become spotless by the end of the day. Region 9347 was quiet and stable, as were regions 9348 and 9349. New region 9350 rotated into view at the northeast limb. Flares and CMEs A total of 2 C class events were recorded on February 11. Region 9338 produced a C2.1 flare at 09:12 UT. A C6.5 long duration event peaked at 01:23 UT. Its source was near the northwest limb but not inside any of the numbered regions. A partial halo CME was observed soon after the flare and could perhaps influence the geomagnetic field on February 13 or 14. The flare caused a minor enhancement in the above 10 MeV proton flux most of the day. February 10: A filament eruption began at approximately 05:24 UT. LASCO-EIT images indicate that the eruption was fairly extensive and occurred in the northwest quadrant near the central meridian. A full halo CME was produced and could impact Earth's magnetosphere sometime between late on Feb.12 and noon on Feb.13. The background x-ray flux is at the class B3 level. Coronal holes A coronal hole in the northern hemisphere could rotate into a geoeffective position on February 12-13. Forecast The geomagnetic field is expected to be quiet to unsettled on February 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 N22W91 0000 AXX 9334 2001.02.01 5 N12W55 0040 CSO 9335 2001.02.03 2 N11W43 0000 AXX 9337 2001.02.03 S28W27 plage 9338 2001.02.04 21 S20W28 0210 DAO 9339 2001.02.04 9 S08W19 0120 CAO 9340 2001.02.05 S11W75 plage 9341 2001.02.06 3 S09W43 0010 BXO 9342 2001.02.06 S26W10 plage 9343 2001.02.07 N03W44 plage 9344 2001.02.08 N30W27 plage 9345 2001.02.08 6 S20W20 0020 CSO 9346 2001.02.09 N18W80 plage 9347 2001.02.09 4 N04E38 0050 DAO 9348 2001.02.10 6 N11W08 0010 BXO 9349 2001.02.10 1 N28E46 0040 HSX 9350 2001.02.11 1 N18E69 0060 HSX Total number of sunspots: 59 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) 2001.02 160.8 (1) 61.9 (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]