Solar Terrestrial Activity Report [Image] Last update February 17, 2002 at 05:05 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 on February 16. Solar wind speed ranged between 309 and 382 km/sec. A solar wind shock was recorded at 01:56 UTC at SOHO on February 17. 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 initially only weakly southwards, then swung northwards. Just before 05h UTC a stronger southwards swing is occurring and this could lead to at least an active geomagnetic field. Solar flare activity was low. Solar flux was 193.5, the planetary A index was 5 (3-hour K indices: 2001 1222, Boulder K indices: 2111 3322). Region 9819 was quiet and stable and will rotate over the southwest limb on Feb.18. Region 9823 decayed into spotless plage. Region 9824 was quiet and stable. Region 9825 decayed significantly and was quiet. There is still a chance of an isolated minor M class flare. Region 9828 was again spotless all day in all available images, yet for the second consecutive day SEC/NOAA recorded 2 spots. Region 9829 was quiet and stable. Region 9830 developed quickly early in the day but seems to have stabilized since then. A minor M class flare is possible. New region 9831 emerged in the southwest quadrant. Flares and CMEs A total of 3 C class events were recorded on February 16, none of the flares were optically correlated. 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 active, possibly with minor storm intervals on February 17 caused by the arrival of a CME. Quiet to unsettled is likely on February 18-19. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair but is likely to become poor to very poor soon. 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 1 S28W72 0010 AXX 9820 2002.02.07 N14W77 plage 9822 2002.02.08 N17W44 plage 9823 2002.02.09 S03W75 plage 9824 2002.02.09 2 N23W22 0140 CSO 9825 2002.02.09 32 N13W24 0290 FAI beta-gamma 9826 2002.02.10 S22W41 plage 9828 2002.02.11 2 S15W18 0010 BXO actually spotless! 9829 2002.02.14 4 S06E52 0040 ESO 9830 2002.02.14 21 S20E44 0210 FAI 9831 2002.02.16 2 S11W41 0010 BXO Total number of sunspots: 64 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) 2002.02 210.9 (1) 122.1 (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]