Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update October 4, 1999 at 03:10 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 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] [NEW! Experimental solar data chart January 1998-September 1999] Recent development The geomagnetic field was quiet to unsettled on October 3. Solar wind speed ranged between 381 and 440 km/sec. Solar flare activity was low. Solar flux was 134.5, the planetary A index was 10 (3-hour Kp indices: 2133 3322, Boulder K indices: 1133 2312). Region 8710 was quiet and stable, the region is spotless early on October 4. Region 8713 was quiet and stable but appears to be spotless early on October 4. Region 8714 was quiet and stable. Region 8716 should produce further C flares and has the potential to generate a minor M class flare. New region 8717 emerged in the southwest quadrant. New region 8718 emerged in the southeast quadrant near the central meridian. New region 8719 rotated into view at the southeast limb. New region 8720 rotated into view at the northeast limb near region 8716. New region 8721 rotated into view at the southeast limb near region 8719. Flares and CMEs A total of 3 C flares were noted on October 3 with region 8716 producing 2 and region 8720 the source of 1 flare. The background x-ray flux is at the class B4 level. Coronal holes A coronal hole in the southern hemisphere was in a geoeffective position on October 1-3. A coronal hole in the northern hemisphere may have been in a geoeffective position on September 30-October 1. Forecast The geomagnetic field is expected to be quiet to active with a possibility of minor storm intervals on October 4-6 due to a coronal stream from a southern hemisphere coronal hole. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally fair to 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 8708 990922 S11W87 plage 8709 990924 S15W69 plage 8710 990926 1 N22W13 0000 AXX 8712 990929 S11W48 plage 8713 990929 1 S12E06 0000 AXX 8714 990929 2 N14E17 0020 HSX 8715 990930 N11E03 plage 8716 991002 5 N20E60 0200 CSO 8717 991003 2 S26W59 0010 BXO 8718 991003 3 S27E02 0010 BXO 8719 991003 3 S20E50 0060 CSO 8720 991003 4 N14E65 0020 BXO 8721 991003 6 S17E56 0050 CSO Total number of sunspots: 27 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 (84.5 predicted, +0.7) 9905 148.4 106.4 (88.7 predicted, +4.2) 9906 169.8 137.4 (92.8 predicted, +4.1) 9907 165.6 113.5 9908 170.7 93.7 9909 135.7 70.6 9910 127.5 (1) 7.5 (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]