Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update October 12, 1999 at 01:55 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 active on October 11. Solar wind speed ranged between 501 and 695 km/sec under the influence of a coronal stream. Solar flare activity was low. Solar flux was 167, the planetary A index was 23 (3-hour Kp indices: 4244 4434, Boulder K indices: 4244 4324). Region 8714 was quiet and stable and will be rotating over the west limb today. Regions 8716 and 8719 were quiet and stable. Region 8720 decayed slowly and was quiet, the region appears to be spotless early on October 12. Region 8721 was quiet and stable. Region 8723 decayed into spotless plage. Region 8724 rotated off the visible disk. Regions 8725 and 8727 were quiet and stable. Region 8728 developed further and has M class flaring potential. Region 8729 was quiet and stable. Region 8730 decayed into spotless plage. New region 8731 was split off from region 8729, the region could produce a minor M flare. An active region is approaching the southeast limb. Flares and CMEs A total of 3 C flares were noted on October 11, all were optically unaccounted. The background x-ray flux is at the class B7 level. Coronal holes A large coronal hole mainly in the southern hemisphere but stretching across the equator and into the northern hemisphere in the eastern parts, will be in a geoeffective position October 9-13. Forecast The geomagnetic field is expected to be quiet to active on October 12-14 with a chance of minor storm intervals. Unsettled to minor storm, possibly with major storm intervals, is likely on October 15-16 due to a well placed coronal hole. 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 8714 990929 2 N14W83 0030 HSX 8716 991002 6 N23W47 0180 CKO 8719 991003 3 S21W57 0080 CSO 8720 991003 4 N13W38 0010 BXO 8721 991003 1 S16W50 0010 HRX 8722 991004 N15W70 plage 8723 991004 N20W12 plage 8725 991005 1 S24W13 0030 HAX 8726 991006 S19W44 plage 8727 991007 4 N18E01 0020 CAO 8728 991008 22 N22E38 0560 EKI 8729 991009 14 N12E44 0030 BXO 8730 991010 S11W07 plage 8731 991011 6 N10E62 0120 EAO Total number of sunspots: 63 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 142.5 (1) 53.3 (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]