Solar Terrestrial Activity Report [Image] Last update September 2, 2000 at 05:10 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 unsettled to active on September 1. Solar wind speed ranged between 468 and 580 km/sec under the influence of a coronal stream. Solar flare activity was low. Solar flux was 157.7, the planetary A index was 17 (3-hour K indices: 3344 3333, Boulder K indices: 3344 3322). Region 9140 decayed slowly, further C flares are possible before the region rotates over the west limb on September 3. 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, the region is rotating off the visible disk. Region 9145 was mostly unchanged and quiet. Region 9147 was quiet and stable. Region 9148 decayed into spotless plage. Region 9149 developed slowly. Occasional C class flares are likely and there is a possibility of a minor M class flare. Region 9150 was quiet and stable, as were regions 9151, 9152 and 9153. Region 9154 was quiet and has become spotless early on September 2. Flares and CMEs A total of 3 C class event were recorded on September 1. Region 9143 was at the center of a long duration C1.6 event peaking at 06:06 UTC. A filament eruption and an accompanying almost full coronal mass ejection was observed. The CME was visible all around the solar disk except off the northern part of the northeast limb. A terrestrial impact is possible on September 4. Region 9140 produced the largest x-ray event of the day, a C9.1/1N flare. A moderate type II sweep occurred in connection with the flare, however, a CME from this event near the northwest limb is unlikely to influence Earth. A filament eruption to the south and southwest of region 9148 was observed early on September 2, there may have been a partial halo CME associated with this event. The background x-ray flux is at the class B5 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 2 and quiet to unsettled on September 3. Quiet to minor storm is possible on September 3. 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 9 N11W67 0130 DAO 9142 20000824 1 N16W32 0020 HSX 9143 20000824 9 S18W32 0080 DSO 9144 20000825 5 N26W80 0070 CAO 9145 20000827 6 S09W08 0040 CSO 9146 20000827 S28W13 plage 9147 20000828 5 N05E14 0100 CSO 9148 20000828 S18W07 plage 9149 20000828 27 N12E18 0380 EKI beta-gamma 9150 20000830 1 N11E38 0000 AXX 9151 20000831 6 N05E28 0020 CAO 9152 20000831 1 N17E61 0040 HSX 9153 20000831 3 S33E16 0030 CRO 9154 20000831 2 S21E44 0000 AXX Total number of sunspots: 75 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 2000.09 157.7 (1) 6.5 (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]