Solar Terrestrial Activity Report [Image] Last update October 23, 2001 at 03:50 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update October 3, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update October 3, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update October 3, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update October 16, 2001)] Recent development The geomagnetic field was active to severe storm on October 22. Solar wind speed ranged between 481 and 731 km/sec. There was no distinct solar wind shock associated with the arrival of the second halo CME observed on October 19. Having decreased early on, geomagnetic disturbance levels increased again after 09h UT and reached severe storm levels during the 15-18h UTC interval. Solar flare activity was high. Solar flux was 232.7, the planetary A index was 66 (3-hour K indices: 6546 5765, Boulder K indices: 6536 5564). Region 9661 decayed and is about to rotate off the visible disk. Region 9667 was quiet and stable. Region 9669 decayed slowly producing several C flares. Region 9670 developed slowly and could produce occasional M class flares. Region 9671 decayed slowly and was quiet. Region 9672 developed two magnetic delta structures, one of them is strong and embedded within the main penumbra. Further major flares are likely as long as the delta persists. Region 9673 was quiet and stable, as were regions 9675 and 9676. Region 9674 decayed and appeared to be spotless by the end of the day. New region 9677 emerged in the northeast quadrant. Flares and CMEs A total of 6 C, 2 M and 1 X class events were recorded on October 22. Region 9658 produced an M1.0 flare at 00:40 UTC. Region 9669 generated a C6.8/1F flare at 03:59 and a C7.5 flare at 12:17 UTC. Region 9672 was the source of a C5.6 flare at 11:41, a major M6.7/2N long duration event peaking at 15:08 (with associated weak type IV and moderate type II radio sweeps) and a major X1.2/2B flare at 17:59 UTC (with an associated weak type II radio sweep). A large and bright full halo CME was observed in LASCO C3 images. The CME will impact Earth, probably during the latter half of October 24, and cause minor to severe (possibly very severe) geomagnetic storming. Region 9672 was the likely source of another major flare at 02:23 UTC on October 23, this time an M6.5 event. The background x-ray flux is at the class C1 level. Coronal holes What could be a coronal hole in the northern hemisphere will rotate into a geoeffective position on October 22-24. Forecast The geomagnetic field is expected to be unsettled to major storm on October 23 and unsettled to severe storm on October 24. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is useless. 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 9661 2001.10.10 6 N14W76 0390 EAO 9663 2001.10.11 S16W82 plage 9666 2001.10.14 S11W73 plage 9667 2001.10.14 1 N25W36 0010 HRX 9669 2001.10.15 24 N14W24 0120 EAI 9670 2001.10.16 20 S18W07 0470 FKO beta-gamma 9671 2001.10.17 6 N13W39 0050 CAO 9672 2001.10.18 17 S18E13 0440 DKI beta-gamma-delta 9673 2001.10.18 9 N02E18 0140 CSO 9674 2001.10.19 6 S09W08 0020 BXO 9675 2001.10.20 4 S15E44 0040 CSO 9676 2001.10.20 2 N15E45 0060 CSO 9677 2001.10.21 2 N20E48 0030 CSO Total number of sunspots: 97 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 2000.09 182.1 109.7 116.3 (-2.3) 2000.10 167.4 99.4 114.5 (-1.8) 2000.11 178.8 106.8 112.7 (-1.8) 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 (107.7 predicted, +2.9) 2001.05 147.1 96.6 (108.1 predicted, +0.4) 2001.06 173.0 134.0 (106.3 predicted, -1.8) 2001.07 131.3 82.2 (105.1 predicted, -1.2) 2001.08 162.9 106.8 (105.7 predicted, +0.6) 2001.09 233.2 150.7 (105.1 predicted, -0.6) 2001.10 198.8 (1) 132.2 (2) (102.3 predicted, -2.8) 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]