Solar Terrestrial Activity Report [Image] Last update February 18, 2002 at 04:30 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 2, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update February 2, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update February 2, 2002)] [Historical solar and geomagnetic data charts 1954-2001 (last update January 12, 2002)] Recent development The geomagnetic field was quiet to active on February 17. Solar wind speed ranged between 369 and 440 km/sec. A solar wind shock was recorded at SOHO at 01:56 UTC. Solar wind speed increased abruptly from 370 to 410 km/sec. The source of this shock is likely the halo CME observed on February 14. The interplanetary magnetic field was moderately southwards at 05h UTC and was otherwise mainly northwards, causing only a weak disturbance. Solar flare activity was low. Solar flux was 196.6, the planetary A index was 8 (3-hour K indices: 1342 2222, Boulder K indices: 2332 3322). Region 9819 decayed into spotless plage early in the day. Region 9824 was quiet and stable. Region 9825 decayed significantly, particularly in the trailing spots section, and lost many spots. Region 9829 decayed and was spotless at about noon. Region 9830 developed further and has developed a magnetic delta structure in the leading penumbra. M class flares are possible. Region 9831 decayed into spotless plage. A new region emerged just to the northeast of region 9830, for non obvious reasons SEC/NOAA determined that this region is part of region 9830. Flares and CMEs A total of 8 C class events were recorded on February 17. The background x-ray flux is at the class B7 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 18-20. 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 Location region numbered no. at Area Classification Comment sunspots midnight 9819 2002.02.05 2 S31W83 0010 BXO actually spotless 9822 2002.02.08 N17W57 plage 9823 2002.02.09 S03W88 plage 9824 2002.02.09 1 N23W35 0140 HSX 9825 2002.02.09 24 N12W36 0290 FAI beta-gamma spot count too high! 9826 2002.02.10 S22W54 plage 9828 2002.02.11 S15W31 plage 9829 2002.02.14 5 S05E36 0050 CSO now spotless 9830 2002.02.14 28 S18E32 0360 FAI beta-gamma-delta 9831 2002.02.16 1 S11W52 0000 AXX now spotless Total number of sunspots: 61 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.8 2000.12 173.6 104.4 112.0 (-0.7) 2001.01 166.6 95.6 108.7 (-3.3) 2001.02 146.6 80.6 104.1 (-4.6) 2001.03 177.7 113.5 104.8 (+0.7) 2001.04 177.7 107.7 107.6 (+2.8) 2001.05 147.1 96.6 108.7 (+1.1) 2001.06 173.0 134.0 109.8 (+1.1) 2001.07 131.3 82.2 111.7 (+1.9) 2001.08 162.9 106.8 (113.5 predicted, +1.8) 2001.09 233.2 150.7 (113.3 predicted, -0.2) 2001.10 207.6 125.6 (111.0 predicted, -2.3) 2001.11 210.6 106.5 (109.6 predicted, -1.4) 2001.12 235.1 131.8 (106.2 predicted, -3.4) 2002.01 226.6 113.9 (102.6 predicted, -3.6) 2002.02 210.0 (1) 126.4 (2) (101.2 predicted, -1.4) 1) Running average based on the daily 20:00 UT solar flux value at 2800 MHz. 2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number 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]