Solar Terrestrial Activity Report [Planetary A Index, Solar Flux and SEC sunspot number] Last update October 3, 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 quiet to active on October 2. Solar wind speed ranged between 387 and 464 km/sec. Solar flare activity was low. Solar flux was 126.3, the planetary A index was 15 (3-hour Kp indices: 3443 3322, Boulder K indices: 2443 2222). Region 8710 decayed slowly and could become spotless in a day or two. Region 8711 decayed into spotless plage, as did region 8712. Regions 8713 and 8714 were quiet and stable. New region 8716 rotated partly into view at the northeast limb, the region could be capable of producing an isolated minor M class flare. An active region at the southeast limb will be numbered today, it could be capable of minor M class flaring as well. A region appears to be emerging in the southwest quadrant. Flares and CMEs A total of 9 C flares were recorded on October 2. A C3.6 flare at 18:28 was attributed to region 8716, the remainder of the flares were optically unaccounted. The background x-ray flux is at the class B3 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 on October 3. A coronal stream is likely to cause unsettled to minor storm conditions October 4-6. Low frequency (below 2 MHz) radio wave propagation along east-west paths over high and upper middle latitudes is generally 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 S11W74 plage 8709 990924 S15W56 plage 8710 990926 1 N21E00 0010 AXX 8711 990928 N22W84 plage 8712 990929 S11W48 plage 8713 990929 1 S12E19 0020 HRX 8714 990929 1 N14E30 0020 HSX 8715 990930 N11E16 plage 8716 991002 4 N21E70 0160 CSO Total number of sunspots: 7 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 124.0 (1) 3.7 (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]