Solar Terrestrial Activity Report [Image] Last update September 11, 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 10. Solar wind speed ranged between 273 and 321 km/sec. Solar flare activity was low. Solar flux was 244.5, the planetary A index was 5 (3-hour K indices: 2111 2322, Boulder K indices: 2111 1311). Region 9605 decayed and was spotless by the end of the day. Region 9606 decayed fairly quickly and could loose most of its remaining spots today. Region 9607 decayed significantly and was mostly quiet. Region 9608 developed slowly and has a very large main penumbra containing a couple of magnetic delta configurations. 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 developed early in the day and was quiet. Minor M class flares are possible before the region rotates out of view late on September 12. Region 9612 developed slowly and was quiet. Region 9615 was quiet and stable, the region could become spotless today. A couple of active regions are at or approaching the east limb and should rotate into view within a couple of days. Flares and CMEs A total of 10 C class events were observed on September 10. Region 9608 produced a C9.7/1N flare at 05:16, a C6.9 flare at 08:25, a C1.9 flare at 14:20, a C2.4/1F flare at 20:31 and a C3.6 flare at 23:48 UTC. Region 9607 generated a C8.1 flare at 15:22 UTC while region 9610 managed a C2.3 flare at 18:10 UTC. September 9: 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 12. Forecast The geomagnetic field is expected to be quiet to unsettled on September 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 fair to 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 9602 2001.09.01 S07W89 plage 9603 2001.09.02 S08W42 plage 9605 2001.09.03 1 S19W45 0020 HRX now spotless 9606 2001.09.03 18 S18W36 0210 DAO 9607 2001.09.04 20 S17W09 0200 EAO beta-gamma 9608 2001.09.05 52 S27E07 1110 FKC beta-gamma-delta 9610 2001.09.06 28 S13E22 0540 EKI 9611 2001.09.07 9 N10W64 0370 DKO 9612 2001.09.07 8 N21E00 0040 CSO 9614 2001.09.08 N15W47 plage 9615 2001.09.08 1 N11E36 0010 AXX Total number of sunspots: 137 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) 2001.09 218.1 (1) 69.5 (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]