Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update October 29, 1999 at 03:20 UTC. Next update after 12 UTC on October 31 due to DXLC board meeting. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update October 2, 1999)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update October 2, 1999)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update October 2, 1999)] [Historical solar and geomagnetic data charts 1954-1999] [Experimental solar data chart January 1998-September 1999] Recent development The geomagnetic field was quiet to minor storm on October 28. Solar wind speed ranged between 379 and 461 km/sec. A solar wind shock was observed at ACE near 11:25 UTC. The interplanetary magnetic field swung strongly southwards shortly after the shock and weakened gradually towards the end of the day. The source of the shock was likely the partial halo CME observed on October 25. Solar flare activity was low. Solar flux was 183.9, the planetary A index was 16 (3-hour Kp indices: 2131 5433, Boulder K indices: 2232 5442). Region 8738 was quiet and stable and will rotate off the visible disk today. Region 8739 decayed significantly and is unlikely to produce other than occasional C flares and perhaps a minor M flare. Region 8741 decayed slowly and was quiet. Region 8742 was mostly unchanged and could produce M class flares. Region 8743 was quiet and stable, as were regions 8744 and 8745. Region 8744 appears to be spotless early on October 29. Region 8746 was quiet and stable. New region 8747 rotated into view at the northeast limb, it produced several sub flares during the day. Flares and CMEs 2 C flares were recorded on October 28 with regions 8739 and 8747 each producing a single C1 flare. The background x-ray flux is at the class B6 level. Coronal holes A small, isolated coronal hole in the northern hemisphere was in a geoeffective position on October 26. Forecast The geomagnetic field is expected to be quiet to active on October 29. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally 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 8738 991020 1 N17W80 0000 AXX 8739 991020 35 S11W37 0590 FKI beta-gamma 8741 991022 19 S25W16 0150 EAO 8742 991023 29 N08E17 0460 EKI beta-gamma 8743 991025 4 S15W18 0010 BXO 8744 991025 3 N10E03 0010 BXO 8745 991026 7 S15E42 0180 CAO 8746 991027 4 S15E14 0010 BXO 8747 991028 4 N10E59 0040 CRO Total number of sunspots: 106 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 9807 114.0 66.6 65.5 (+3.0) 9808 136.0 92.2 67.8 (+2.3) 9809 138.3 92.9 69.5 (+1.7) 9810 117.2 55.5 70.5 (+1.0) 9811 140.1 74.0 73.0 (+2.5) 9812 150.1 81.9 77.9 (+4.9) 9901 140.6 62.0 82.6 (+4.7) 9902 141.9 66.3 84.6 (+2.0) 9903 126.3 68.8 83.8 (-0.8) 9904 117.2 63.9 (84.9 predicted, +1.1) 9905 148.4 106.4 (89.5 predicted, +4.6) 9906 169.8 137.4 (93.6 predicted, +4.1) 9907 165.6 113.5 9908 170.7 93.7 9909 135.7 70.6 9910 164.3 (1) 148.9 (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 in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]