Solar Terrestrial Activity Report [Image] Last update September 6, 2000 at 04:35 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 unsettled on September 5. Solar wind speed ranged between 329 and 419 km/sec. Solar flare activity was low. Solar flux was 180.2, the planetary A index was 8 (3-hour K indices: 2222 2333, Boulder K indices: 2211 1323). Region 9145 was quiet and stable. Region 9147 decayed slowly and was quiet. Region 9149 was mostly unchanged and will likely continue to produce C class flares. A minor M class flare is possible. Region 9151 developed slowly and could start producing C flares. Region 9152 was quiet and stable. Region 9153 decayed into spotless plage. Region 9154 continued to develop quickly, however, the region lost its magnetic delta configuration. C and minor M class flares are possible. Region 9155 was quiet and stable. Flares and CMEs A total of 11 C class events were recorded on September 5. Region 9154 produced a C6.3 flare at 00:08, a C2.2 flare at 08:18, a C1.6 flare at 21:25 and a C1.6 flare at 21:51 UTC. Region 9149 generated a C2.6 flare at 19:13 UTC. 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. September 4: A large filament eruption occurred in the northwest quadrant started at 05:12 UTC. A partial halo CME covering the northern hemisphere limbs as well as the most of the southwest limb was observed in LASCO C3 images. The CME will likely affect Earth on September 7 but could arrive late on September 6. The background x-ray flux is at the class B7 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions.. Forecast The geomagnetic field is expected to be quiet to unsettled on September 6 and unsettled to major storm on September 7-8. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 9142 20000824 N16W89 plage 9143 20000824 S19W88 plage 9145 20000827 1 S10W63 0030 HAX 9146 20000827 S23W71 plage 9147 20000828 2 N06W40 0040 HSX 9148 20000828 S18W59 plage 9149 20000828 24 N13W35 0230 EAI beta-gamma 9150 20000830 N12W14 plage 9151 20000831 12 N09W21 0050 DAO 9152 20000831 2 N18E09 0020 HAX 9153 20000831 S32W36 plage 9154 20000831 30 S19W07 0390 EAI beta-gamma 9155 20000903 3 S10E07 0010 BXO Total number of sunspots: 74 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 2000.09 163.4 (1) 28.9 (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]