Solar Terrestrial Activity Report [Image] Last update September 1, 2000 at 04:55 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update August 4, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update August 4, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update August 4, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update August 10, 2000)] Recent development The geomagnetic field was unsettled to active on August 31. Solar wind speed ranged between 493 and 588 km/sec under the influence of a coronal stream. Solar flare activity was low. Solar flux was 162.9, the planetary A index was 15 (3-hour K indices: 4334 3333, Boulder K indices: 4334 3333). Region 9140 is decaying slowly, the region was quiet. Region 9142 was quiet and stable. Region 9143 decayed slowly and was mostly quiet. Occasional C class flares are possible. Region 9144 decayed slowly and was quiet. Region 9145 was mostly unchanged and quiet. Region 9147 developed slowly and was quiet. Region 9148 was quiet and stable. Region 9149 was mostly unchanged. Occasional C class flares are likely and there is a possibility of a minor M class flare. Region 9150 was quiet and stable. New region 9151 emerged in the northeast quadrant. New region 9152 rotated into view at the northeast limb. New region 9153 emerged in the southeast quadrant. New region 9154 rotated into view at the southeast limb. Flares and CMEs Only 1 C class event was recorded on August 31. Region 9143 produced a C1.6 flare at 06:56 UTC. August 29: A long duration C4.2 event started at 22:35 UTC and peaked at 00:08 UTC on August 30. This was a large filament eruption occurring in the vicinity of region 9148 and 9143 in the southeast quadrant. A CME was observed off the southeast limb, the south pole and part of the southwest limb making this a partial halo CME. There is a minor chance of a weak terrestrial impact on September 2. The background x-ray flux is at the class B4 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions.. Forecast The geomagnetic field is expected to be quiet to active on September 1. 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 9140 20000822 19 N10W51 0170 EAO 9142 20000824 1 N16W18 0020 HSX 9143 20000824 14 S18W20 0120 EAO 9144 20000825 7 N26W65 0100 EAO 9145 20000827 5 S10E07 0050 CSO 9146 20000827 S28E00 plage 9147 20000828 5 N05E26 0110 CSO 9148 20000828 2 S18E06 0000 AXX 9149 20000828 22 N12E32 0310 EAI beta-gamma 9150 20000830 1 N11E51 0010 HRX 9151 20000831 4 N05E42 0020 CRO 9152 20000831 1 N17E75 0020 HRX 9153 20000831 2 S33E27 0020 HRX 9154 20000831 1 S22E57 0020 HRX Total number of sunspots: 84 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 (115.7 predicted, +2.9) 2000.03 208.2 138.5 (118.2 predicted, +2.5) 2000.04 184.2 125.3 (120.4 predicted, +2.2) 2000.05 184.9 120.8 (121.2 predicted, +0.8) 2000.06 179.8 124.9 (122.8 predicted, +1.6) 2000.07 202.3 169.1 2000.08 163.0 (1) 166.6 (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]