Solar Terrestrial Activity Report [Image] Last update September 5, 2001 at 04:00 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 unsettled to active on September 4. Solar wind speed ranged between 449 and 568 km/sec under the influence of a coronal stream. Solar flare activity was moderate. Solar flux was 218.4, the planetary A index was 20 (3-hour K indices: 3443 4433, Boulder K indices: 3442 4332). Region 9591 rotated quietly off the visible disk. Region 9596 was quiet and stable. Region 9599 decayed further and was quiet. Region 9601 was mostly unchanged and could produce a major flare. Region 9603 was quiet and stable. Region 9604 developed further and was quiet. Regions 9605 and 9606 appears to be one region now with region 9606 continuing to develop at a moderate pace. Further M class flaring is possible from this region. New region 9607 rotated into view at the southeast limb. Another region, to the southeast of region 9607, is currently rotating into view and is very hot and likely capable of major flare production. Flares and CMEs A total of 4 C and 3 M class events were observed on September 4. Region 9601 produced a C5.0 flare at 04:18 and an M3.7/1N flare at 21:59 UTC. Region 9606 generated a C3.9 flare at 11:56, a C9.0 long duration event peaking at 15:53, a C7.4 flare at 17:24 and an M1.8/1N flare at 20:17 UTC. A long duration M1.0 event peaked at 19:25 UTC and likely had its source in the region at the southeast limb. The background x-ray flux is at the class C3 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 5-6. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to 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 9591 2001.08.21 1 S19W92 0100 HKX 9596 2001.08.25 1 N21W48 0140 HAX 9597 2001.08.26 N19W67 plage 9599 2001.08.27 1 S18W47 0030 HSX 9601 2001.08.27 49 N13W22 0780 FKC beta-gamma 9602 2001.09.01 S07W11 plage 9603 2001.09.02 1 S08E36 0030 HSX 9604 2001.09.03 5 S22W76 0250 DAO 9605 2001.09.03 6 S19E39 0070 CSO 9606 2001.09.03 10 S17E45 0150 DAO 9607 2001.09.04 4 S16E68 0210 EAO Total number of sunspots: 78 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 (102.8 predicted, -1.3) 2001.04 177.7 108.2 (102.0 predicted, -0.8) 2001.05 147.1 97.3 (100.5 predicted, -1.5) 2001.06 173.0 134.0 (97.7 predicted, -2.8) 2001.07 131.3 82.2 (95.9 predicted, -1.8) 2001.08 162.9 106.8 (96.4 predicted, +0.5) 2001.09 195.9 (1) 21.0 (2) (95.4 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]