Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update October 1, 1999 at 04:05 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update September 1, 1999)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update September 1, 1999)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update September 1, 1999)] [Historical solar and geomagnetic data charts 1954-1999] Recent development The geomagnetic field was quiet to major storm on September 30. Solar wind speed ranged between 492 and 607. Solar flare activity was low. Solar flux was 124.8, the planetary A index was 29 (3-hour Kp indices: 4644 4332, Boulder K indices: 5535 3222). Regions 8706, 8710, 8711, 8712, 8713 and 8714 were quiet and stable. New region 8715 emerged in the northeast quadrant. Flares and CMEs A single optically unaccounted C1 flare was the only flare on September 30. Early on October 1 an impulsive C7 flare was observed. The background x-ray flux is at the class B3 level. Coronal holes A coronal hole in the southern hemisphere will rotate into a geoeffective position on October 1-3. A coronal hole in the northern hemisphere was in a possible geoeffective position on September 30-October 1. Forecast The geomagnetic field is expected to be quiet to active on October 1 and quiet to unsettled on October 2. On October 3-6 coronal streams will likely influence the geomagnetic field resulting in unsettled to minor storm conditions. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally poor to very 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 8706 990919 1 N20W66 0050 HSX 8708 990922 S11W48 plage 8709 990924 S15W30 plage 8710 990926 1 N21E25 0020 HSX 8711 990928 4 N23W58 0010 BXO 8712 990929 3 S13W21 0010 BXO 8713 990929 2 S12E45 0020 HSX 8714 990929 1 N12E56 0020 HSX 8715 990930 2 N11E42 0000 AXX Total number of sunspots: 14 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 (83.9 predicted, -0.7) 9904 117.2 63.9 (85.0 predicted, +1.2) 9905 148.4 106.4 (89.4 predicted, +4.4) 9906 169.8 137.4 9907 165.6 113.5 9908 170.7 93.7 9909 135.7 (1) 107.3 (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]