Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update October 11, 1999 at 03:35 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 10. Solar wind speed ranged between 439 and 641 km/sec. Solar wind speed was mostly stable 03-18h UTC following the arrival of a CME. Wind speed increased again from 18h UTC as a coronal stream became the dominant solar wind factor. Solar flare activity was low. Solar flux was 160.5, the planetary A index was 28 (3-hour Kp indices: 3455 5543, Boulder K indices: 2344 4542). Region 8713 was quiet and stable and rotated off the visible disk early on October 11. Region 8714 was quiet and stable, as were regions 8716 and 8719. Region 8718 rotated off the visible disk. Region 8720 decayed slowly and was quiet. Region 8721 was quiet and stable. Region 8722 decayed into spotless plage. Regions 8723, 8724, 8725 and 8727 were quiet and stable. Region 8726 decayed into spotless plage, while regions 8723 and 8724 appear to be spotless early on October 11. Region 8728 developed slowly and has M class flaring potential. Region 8729 was quiet and stable, the region could be split into two regions today. New region 8730 emerged in the southeast quadrant but appears to have become spotless already. Flares and CMEs A total of 4 C flares were noted on October 10. Region 8728 produced a C2.0 flare at 13:56 UTC while 3 flares were optically unaccounted. The background x-ray flux is at the class B6 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 rotate into a geoeffective position October 9-13. Forecast The geomagnetic field is expected to be unsettled to active on October 11-14 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 8713 990929 2 S12W87 0020 CSO 8714 990929 2 N16W71 0020 CSO 8715 990930 N12W85 plage 8716 991002 7 N21W34 0160 CAO 8719 991003 1 S21W44 0050 HSX 8720 991003 8 N14W27 0020 BXO 8721 991003 2 S17W37 0010 HRX 8722 991004 N15W57 plage 8723 991004 3 N20E01 0010 BXO 8724 991005 3 N22W80 0020 BXO 8725 991005 3 S25E02 0030 CSO 8726 991006 S19W31 plage 8727 991007 3 N18E12 0010 BXO 8728 991008 13 N22E50 0340 DHO 8729 991009 14 N12E58 0060 BXO 8730 991010 4 S11E06 0010 BXO Total number of sunspots: 65 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 140.1 (1) 48.0 (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]