Solar Terrestrial Activity Report [Image] Last update February 16, 2001 at 04:55 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 15. Solar wind speed ranged between 496 and 622 km/sec, under the influence of a weakening coronal stream (a stream which became noticable at approximately 18h UT on Feb.14). Solar flare activity was very low. Solar flux was 135.1, the planetary A index was 5 (3-hour K indices: 1123 1121, Boulder K indices: 1123 2121). Regions 9338 and 9339 were quiet and are both rotating off the visible disk. Region 9342 decayed slowly and was quiet, the region is spotless early on Feb.16. Region 9347 was quiet and decayed slowly, the region could become spotless by tomorrow. Region 9348 was quiet and stable. Region 9349 decayed slowly and was quiet. Region 9350 was mostly quiet and stable. New region 9351 emerged in the southwest quadrant, the region is already spotless. New region 9352 rotated into view at the southeast limb. Flares and CMEs No flaring of interest was observed on February 15. A fairly extensive filament eruption started shortly after 12:48 UT in LASCO EIT images, it started near region 9350 and spread northwestwards and southeastwards towards the equator and just into the southern hemisphere. A full halo CME was observed in LASCO C3 images with a front first appearing above the northeast limb and the north pole. The CME will impact the Earth's magnetosphere on February 18. The background x-ray flux is at the class B3 level. Coronal holes A small but well placed coronal hole in the southern hemisphere was in a geoeffective position on February 14-15. Forecast The geomagnetic field is expected to be quiet to unsettled on February 16 and most of February 17. A coronal stream could arrive on February 17 and cause a few unsettled to active intervals. Another disturbance could start on February 18 when a CME arrives at Earth, unsettled to minor storm conditions are possible. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 9337 2001.02.03 S28W79 plage 9338 2001.02.04 1 S20W84 0110 HSX 9339 2001.02.04 1 S09W80 0080 HSX 9342 2001.02.06 1 S27W55 0010 AXX 9344 2001.02.08 N30W79 plage 9345 2001.02.08 S20W71 plage 9347 2001.02.09 5 N04W15 0030 DAO 9348 2001.02.10 8 N15W58 0120 DSO 9349 2001.02.10 1 N28W05 0020 HSX 9350 2001.02.11 1 N18E16 0070 HSX 9351 2001.02.15 3 S21W42 0010 BXO 9352 2001.02.15 2 S23E63 0020 BXO Total number of sunspots: 23 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) 2001.02 155.2 (1) 77.3 (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]