Solar Terrestrial Activity Report [Image] Last update September 13, 2000 at 03:55 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update 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 minor storm on September 12. Solar wind speed ranged between 328 and 415 km/sec. A disturbance was observed at ACE at 07:30 UTC. No CME impact was observed and after noon the disturbance took on weak coronal stream characteristics, the source of the disturbance may have been a coronal hole in the northern hemisphere. Solar flare activity was moderate. Solar flux was 132.6, the planetary A index was 20 (3-hour K indices: 2325 5344, Boulder K indices: 2334 4233). Region 9161 was quiet and stable and could become spotless in a day or two. New region 9162 emerged in the southwest quadrant. New region 9163 emerged in the southwest quadrant near the central meridian. Flares and CMEs A total of 2 C and 1 M class events were recorded on September 12. A long duration C4.6 event peaked at 09:21 UTC, its source is not known. A very large full halo coronal mass ejection was observed following a huge filament eruption in the southern hemisphere. Region 9163, just to the west of the central meridian, was near the center of the eruption which began at 11:00 UTC in LASCO EIT images. This CME could cause a serious disturbance on September 14 and 15 as it impacts Earth, major to very severe storming is possible! The eruption was the source of a proton event as well, the above 10 MeV proton flux has so far peaked near 300 pfu. The background x-ray flux is at the class B3 level. Coronal holes A coronal hole in the southern hemisphere could move into a geoeffective position on September 16-17. Forecast The geomagnetic field is expected to be quiet to unsettled with a chance of active intervals on September 13. Unsettled to very severe storm could be observed on September 14-15. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 9152 20000831 N19W81 plage 9155 20000903 S10W84 plage 9156 20000906 S28W29 plage 9157 20000906 N22W14 plage 9158 20000907 N29E06 plage 9159 20000907 S19W37 plage 9160 20000909 S12W34 plage 9161 20000911 1 N05E38 0000 AXX 9162 20000912 4 S34W36 0020 CRO 9163 20000912 3 S19W10 0010 CSO Total number of sunspots: 8 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 (118.7 predicted, +2.1) 2000.04 184.2 125.3 (119.6 predicted, +0.9) 2000.05 184.9 120.8 (120.4 predicted, +0.8) 2000.06 179.8 124.9 (122.0 predicted, +1.6) 2000.07 202.3 169.1 (124.1 predicted, +2.1) 2000.08 163.0 130.6 2000.09 157.6 (1) 51.4 (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]