Solar Terrestrial Activity Report [Image] Last update September 10, 2000 at 05:35 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update September 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update September 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update September 2, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update August 10, 2000)] Recent development The geomagnetic field was quiet to slightly unsettled on September 9. Solar wind speed ranged between 372 and 478 km/sec. Solar flare activity was moderate. Solar flux was 150.9, the planetary A index was 7 (3-hour K indices: 3222 2212, Boulder K indices: 3212 3311). Region 9147 rotated off the visible disk, as did region 9149. Region 9151 could produce C flares before rotating off the visible disk early on September 11. Region 9152 was quiet and stable, the region is spotless early on September 10. Region 9154 decayed slowly and was mostly quiet. C and minor M class flares are possible. Region 9157 was mostly quiet and stable, as was region 9158. Region 9159 decayed into spotless plage. New region 9160 emerged in the southeast quadrant near the central meridian, the region could already be spotless. Flares and CMEs A total of 3 C and 1 M class events were recorded on September 9. Region 9154 produced a C1.0 flare at 05:20 UTC. Region 9151 generated an M1.6/1N flare at 08:49 UTC. A moderate type II sweep was recorded as well and a partial halo coronal mass ejection was spanning from the north pole to the south pole covering the entire western hemisphere. Parts of this CME could affect Earth on September 12. Region 9158 was the source of a long duration C1.8 event which started at 23:49 on September 9 and peaked at 00:10 UTC on September 10. The background x-ray flux is at the class B5 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. There could be a weak coronal hole in the northern hemisphere. If it is a coronal hole a coronal stream will influence the geomagnetic field from September 11. Forecast The geomagnetic field is expected to be quiet to unsettled on September 10-11. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor but could improve to fair over the next couple of days.. 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 9147 20000828 1 N07W91 0120 HSX 9149 20000828 3 N14W92 0210 DAI 9150 20000830 N12W66 plage 9151 20000831 5 N13W74 0040 DSO 9152 20000831 2 N19W42 0010 BXO 9153 20000831 S32W88 plage 9154 20000831 17 S17W62 0420 EKI 9155 20000903 S10W45 plage 9156 20000906 S28E10 plage 9157 20000906 3 N23E25 0020 BXO 9158 20000907 4 N29E44 0060 HSX 9159 20000907 S19E02 plage 9160 20000909 1 S12E05 0010 AXX Total number of sunspots: 36 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.07 165.6 113.5 94.3 (+1.2) 1999.08 170.7 93.7 97.5 (+3.2) 1999.09 135.7 71.5 102.3 (+4.8) 1999.10 164.8 116.7 107.8 (+5.5) 1999.11 191.5 133.2 110.9 (+3.1) 1999.12 169.8 84.6 111.0 (+0.1) 2000.01 158.1 90.1 112.8 (+1.8) 2000.02 174.1 112.9 116.6 (+3.8) 2000.03 208.2 138.5 (120.1 predicted, +3.5) 2000.04 184.2 125.3 (122.5 predicted, +2.4) 2000.05 184.9 120.8 (123.4 predicted, +0.9) 2000.06 179.8 124.9 (124.9 predicted, +1.5) 2000.07 202.3 169.1 (127.0 predicted, +2.1) 2000.08 163.0 130.6 2000.09 164.8 (1) 46.9 (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]