Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update October 15, 1999 at 03:30 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 unsettled to minor storm on October 14. Solar wind speed ranged between 595 and 706 km/sec under the influence of a coronal stream, a significant increase in wind speed occurred after 21h UTC, corresponding to the expected move into the main part of the coronal stream. Solar flare activity was high. Solar flux was 199.8, the planetary A index was 24 (3-hour Kp indices: 3444 4534, Boulder K indices: 3444 4323). Regions 8716 was quiet and stable, the region will rotate off the visible disk today. Region 8719 rotated over the west limb. Region 8720 reemerged with a couple of spots, however, the region will r> ------------------------------------------------------------------------ Transfer interrupted! on 8725 decayed slowly and was quiet, the region could become spotless today. Region 8727 was quiet and stable. Region 8728 decayed slowly and was quiet. Unless further development occurs, M flares from this region are unlikely as the magnetic gradients are weak. Region 8729 decayed slowly and was quiet. Region 8731 developed further and is a complex, large region with major flaring potential. The region developed a magnetic delta configuration and produced most of the flares observed during the day, including a major impulsive X flare. Further major flares are possible over the next few days. Region 8732 decayed slowly and should be capable of C class flaring. Region 8733 was quiet and stable and could become spotless today. Flares and CMEs A total of 6 C flares and 1 X flare were recorded on October 14. Region 8731 produced 4 of the C flares and an X1.8/1N major flare at 09:00 UTC. A moderately strong type II sweep and a strong type IV sweep accompanied the flare. A coronal mass ejection was observed at 09:26 by LASCO C2 off the east limb, later on an almost full halo CME was evident in LASCO C3 with material observed from the north pole, all around the east limb and off a large part of the southwest limb. Earth could receive a non-direct impact from this CME on October 16 or 17 causing the geomagnetic field activity level to reach active to major storm. October 13: The most interesting event of the day was a large filament eruption in the northern hemisphere. The event started at 07:13 in the northeast quadrant. Development was slow at first and spread towards the southwest crossing the central meridian with the most intense activity between 09 and 11h UTC. LASCO C2 observed a coronal mass ejection starting at 10:06 UTC over the north pole. Material was later evident in all directions, and there is a fairly high chance that the earth will receive a weak impact from this CME on October 16. The background x-ray flux is at the class C1-C2 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, was in a geoeffective position October 9-13. Forecast The geomagnetic field is expected to be active to minor storm on October 15-16 with a chance of major storm intervals. CME impacts are possible on October 16 and 17 and could cause the disturbance level to remain in the active to major storm range. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally 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 Location region numbered no. at Area Classification Comment sunspots midnight 8716 991002 3 N22W83 0100 CSO 8720 991003 2 N17W78 0010 BXO 8723 991004 N20W51 plage 8725 991005 1 S23W53 0010 AXX 8726 991006 S19W83 plage 8727 991007 7 N20W37 0030 DAO 8728 991008 21 N22E00 0330 EKO 8729 991009 15 N12E03 0030 CAO 8730 991010 S11W46 plage 8731 991011 45 N19E24 0790 EKC beta-gamma-delta 8732 991012 21 N20E16 0090 DAO 8733 991012 1 N26W24 0000 AXX Total number of sunspots: 116 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 153.0 (1) 72.9 (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]