Solar Terrestrial Activity Report [Image] Last update February 18, 2001 at 01:55 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 on February 17. Solar wind speed ranged between 341 and 512 km/sec. Solar flare activity was very low. Solar flux was 129.8, the planetary A index was 3 (3-hour K indices: 1001 1221, Boulder K indices: 0001 1211). Region 9347 was spotless all day in all available images, SEC/NOAA mistakenly has listed the region as having a couple of spots. Region 9348 decayed quickly and was spotless by noon. Region 9349 was quiet and stable, as were regions 9350, 9352 and 9353. Region 9354 was spotless early in the day, then developed quickly. Should the current rate of development continue minor M class flares will soon become possible. A new region emerged near the northeast limb, however, SEC/NOAA failed to number it. Flares and CMEs No flaring was observed on February 17. 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 Earth's magnetosphere on February 18. The background x-ray flux is at the class B2 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 active with possible minor storm intervals on February 18. 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 region numbered sunspots at AreaClassification Comment midnight 9342 2001.02.06 S23W78 BXO plage 9345 2001.02.08 S20W84 plage 9347 2001.02.09 2 N05W41 0020 HSX actually spotless! 9348 2001.02.10 4 N17W83 0050 DSO 9349 2001.02.10 1 N28W31 0010 HRX 9350 2001.02.11 1 N18W09 0080 HSX 9351 2001.02.15 S23W66 plage 9352 2001.02.15 3 S22E36 0010 BXO 9353 2001.02.16 6 S23E03 0010 BXO 9354 2001.02.16 8 S08E20 0050 DAO Total number of sunspots: 25 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 (119.5 predicted, -0.3) 2000.09 182.1 109.7 (117.9 predicted, -1.6) 2000.10 167.4 100.1 (116.3 predicted, -1.6) 2000.11 178.8 106.5 (114.4 predicted, -1.9) 2000.12 173.6 104.5 (111.8 predicted, -2.6) 2001.01 166.6 95.7 (108.2 predicted, -3.6) 2001.02 152.2 (1) 85.4 (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]