Solar Terrestrial Activity Report [Image] Last update September 7, 2001 at 03:50 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 6. Solar wind speed ranged between 350 and 433 km/sec. Solar flare activity was low. Solar flux was 222.2, the planetary A index was 8 (3-hour K indices: 2022 3332, Boulder K indices: 2122 2112). Region 9596 was quiet and stable and is rotating over the northwest limb. Region 9599 decayed and could become spotless before rotating over the southwest limb late today. Region 9601 did not change significantly and remains capable of producing another major flare. Region 9603 was quiet and stable. Region 9605 decayed slowly and quietly and had only one spot left by early evening. Region 9606 developed further and could produce at least minor M class flares. Region 9607 was mostly unchanged and may produce M class flares. Region 9608 could be two regions stacked on top of each other, anyway, the region is capable of producing occasional major flares. New region 9609 emerged in the southwest quadrant. New region 9610 rotated partly into view at the southeast limb. The region is warm and may be capable of minor M class flare production. A new region emerged in the northeast quadrant and should have been numbered by SEC/NOAA. Flares and CMEs A total of 4 C class events were observed on September 6. Region 9601 produced a C8.1 flare at 03:46 UTC. Region 9606 generated a C6.7 flare at 13:24 UTC. Region 9607 was the source of a C4.6 flare at 15:36 UTC, while region 9610 managed a C5.0 flare at 19:55 UTC. The background x-ray flux is at the class C3-C4 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 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 Location region numbered no. at Area Classification Comment sunspots midnight 9596 2001.08.25 1 N19W79 0150 HAX 9599 2001.08.27 1 S18W76 0030 HRX area too large 9601 2001.08.27 30 N11W51 0780 FKC beta-gamma-delta 9602 2001.09.01 S07W37 plage 9603 2001.09.02 1 S08E10 0010 HRX Mt.Wilson draws 9605 2001.09.03 9 S18E12 0120 DAO this region with one HSX spot! 9606 2001.09.03 25 S17E19 0360 EKI beta-gamma 9607 2001.09.04 13 S15E42 0220 EAI 9608 2001.09.05 18 S26E56 0720 FKI beta-gamma 9609 2001.09.06 5 S07W53 0040 DSO 9610 2001.09.06 1 S10E71 0070 HAX Total number of sunspots: 104 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) 2001.09 204.0 (1) 33.6 (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]