Solar Terrestrial Activity Report [Image] Last update September 7, 2000 at 06:50 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 active on September 6. Solar wind speed ranged between 351 and 507 km/sec. A fairly strong solar wind shock was observed at 16:10 UTC at ACE. The interplanetary magnetic field was at times strongly southwards but this didn't result in a large increase in geomagnetic activity. Solar flare activity was low. Solar flux was 178.7, the planetary A index was 11 (3-hour K indices: 2121 2334, Boulder K indices: 1121 1333). Region 9145 was quiet and stable and will rotate off the solar disk early on September 8. Region 9147 was quiet and stable. Region 9149 was mostly unchanged and will likely continue to produce C class flares. A minor M class flare is possible. Region 9151 was quiet and stable, as was region 9152. Region 9154 developed slowly. C and minor M class flares are possible. Region 9155 decayed into spotless plage. New region 9156 emerged near the southeast limb. New region 9157 rotated into view at the northeast limb. Flares and CMEs A total of 7 C class events were recorded on September 6. Region 9149 produced a C1.5 flare at 00:25, a C2.7 flare at 01:42 and a C1.7 flare at 03:57 UTC. Region 9154 generated a C2.2 flare at 13:40 and another C2.2 flare at 15:29 UTC. September 5: A filament eruption was observed in progress at 06:36 UTC in the northeast quadrant just one day's rotation away from the central meridian. The associated CME was at least a partial halo one, unfortunately several hours of images after the CME first appeared have not made it to the LASCO C3 movie. There is a fair chance of a terrestrial impact on September 8. The background x-ray flux is at the class B6 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions.. Forecast The geomagnetic field is expected to be unsettled to minor storm on September 7-8. 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 9145 20000827 1 S08W76 0060 HAX 9146 20000827 S23W84 plage 9147 20000828 2 N06W53 0070 HSX 9148 20000828 S18W72 plage 9149 20000828 19 N13W49 0270 EAI beta-gamma 9150 20000830 N12W27 plage 9151 20000831 9 N10W32 0060 CAO 9152 20000831 4 N17W07 0010 BXO 9153 20000831 S32W49 plage 9154 20000831 30 S18W21 0510 EKI beta-gamma 9155 20000903 S10W06 plage 9156 20000906 1 S27E49 0000 AXX 9157 20000906 4 N21E63 0010 BXO Total number of sunspots: 70 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 2000.09 165.9 (1) 33.9 (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]