Solar Terrestrial Activity Report [Image] Last update September 10, 2001 at 04:15 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 1, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update September 1, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update September 1, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update July 27, 2001)] Recent development The geomagnetic field was quiet to unsettled on September 9. Solar wind speed ranged between 289 and 349 km/sec. Solar flare activity was high. Solar flux was 236.2, the planetary A index was 7 (3-hour K indices: 2112 2332, Boulder K indices: 2112 2332). Region 9601 rotated quietly off the visible disk. Region 9605 decayed slowly and was quiet, the region could become spotless today or tomorrow. Region 9606 is decaying and was quiet. Region 9607 was mostly unchanged and has M class flare potential. Region 9608 developed further and is a fairly complex region with magnetic delta configurations within the large main penumbra. Another major flare is possible and it could well be an X class flare, potentially even a proton event. Region 9610 developed slowly and could produce M class flares. Region 9611 became more stable and was quiet. Region 9612 developed early in the day but appeared to be decaying during the latter half of the day. Region 9613 rotated quietly off the visible disk. Region 9614 decayed and was spotless by noon. Region 9615 was quiet and stable. Flares and CMEs A total of 7 C and 6 M class events were observed on September 9. Region 9608 produced a C5.0 flare at 01:45, an M1.9 flare at 02:40, an M1.0 flare at 10:01, a C3.2 flare at 10:56, a C3.0 flare at 11:22, a C7.5 flare at 13:35, an M2.2 flare at 15:26, an M2.0 flare at 18:41, an impulsive major M9.5/2N flare at 20:48 (no obvious CME was observed in connection with this event) and a C4.9 flare at 22:38 UTC. Region 9607 generated a C4.5 flare at 08:05 and an M3.4/1N flare at 15:16 UTC. A strong type II radio sweep was observed in association with the M3/M2 flares in regions 9607 and 9608 from 15:17 UTC. LASCO C3 images indicate that a CME was produced. Although most of the ejected material was observed above the east limb, this may have been a full halo CME. The background x-ray flux is at the class C2 level. Coronal holes A coronal hole in the northern hemisphere will rotate into a geoeffective position on September 11. Forecast The geomagnetic field is expected to be quiet to unsettled on September 10-11. A CME could cause a disturbance on September 12. 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 Location region numbered no. at Area Classification Comment sunspots midnight 9601 2001.08.27 1 N13W93 0210 HKX 9602 2001.09.01 S07W76 plage 9603 2001.09.02 S08W29 plage 9605 2001.09.03 5 S19W30 0050 DSO 9606 2001.09.03 33 S18W22 0210 EAO 9607 2001.09.04 25 S17E03 0260 EAI beta-gamma 9608 2001.09.05 60 S27E18 1050 FKC beta-gamma-delta 9610 2001.09.06 26 S14E34 0410 EAO 9611 2001.09.07 10 N10W51 0170 DAO 9612 2001.09.07 13 N21E12 0040 DSO 9613 2001.09.07 4 S17W83 0040 CSO 9614 2001.09.08 3 N15W34 0010 AXX 9615 2001.09.08 1 N11E49 0010 AXX Total number of sunspots: 181 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.03 208.2 138.5 119.9 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.7 2000.08 163.0 130.5 118.6 (-1.1) 2000.09 182.1 109.7 116.3 (-2.3) 2000.10 167.4 99.4 114.5 (-1.8) 2000.11 178.8 106.8 112.8 (-1.7) 2000.12 173.6 104.4 112.1 (-0.7) 2001.01 166.6 95.6 108.8 (-3.3) 2001.02 146.6 80.6 104.1 (-4.7) 2001.03 177.7 113.5 (103.8 predicted, -0.3) 2001.04 177.7 108.2 (104.1 predicted, +0.3) 2001.05 147.1 97.3 (102.6 predicted, -1.5) 2001.06 173.0 134.0 (99.8 predicted, -2.8) 2001.07 131.3 82.2 (98.0 predicted, -1.8) 2001.08 162.9 106.8 (98.5 predicted, +0.5) 2001.09 215.1 (1) 62.3 (2) (97.5 predicted, -1.0) 1) Running average based on the daily 20:00 UT solar flux value at 2800 MHz. 2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number 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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]