Solar Terrestrial Activity Report [Image] Last update September 15, 2001 at 05:00 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 quiet to active on September 14. Solar wind speed ranged between 366 and 480 km/sec. A weak solar wind shock was observed just before 21h UTC at ACE. The interplanetary magnetic field was briefly moderately southwards after the shock and this caused the only active interval of the day. The IMF had been northwards all the time since the CME impact observed early in the day. Solar flare activity was moderate. Solar flux was 236.6, the planetary A index was 10 (3-hour K indices: 3112 3324, Boulder K indices: 3212 2114). Region 9607 decayed further and was quiet. Region 9608 was mostly unchanged and could still produce a major flare. Region 9610 decayed significantly losing many spots towards the end of the day. Minor M class flares are still possible. Region 9612 decayed and could become spotless before rotating off the visible disk on September 17. Region 9616 was generally unchanged and could produce further M class flares. Region 9617 decayed slowly and quietly. Region 9618 was quiet and stable. Region 9619 decayed during the latter half of the day. Flares and CMEs A total of 6 C and 1 M class events were observed on September 14. Region 9616 produced a C5.8 flare at 06:06, a C3.7 flare at 09:04 and an M3.7 flare at 21:50 UTC. The latter flare triggered a large filament eruption to the west of the region. This eruption may have produced a CME which could impact Earth on September 17 or 18. The background x-ray flux is at the class C1-C2 level. Coronal holes A coronal hole in the northern hemisphere was in a geoeffective position on September 12-14. Forecast The geomagnetic field is expected to be quiet to active on September 15-16. 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 no. Location at region numbered sunspots midnight Area Classification Comment 9607 2001.09.04 1 S18W63 0070 HAX 9608 2001.09.05 34 S28W44 1020 FKC beta-gamma 9610 2001.09.06 48 S14W31 0400 EAC beta-gamma 9612 2001.09.07 13 N18W55 0050 DAO 9615 2001.09.08 N11W16 plage 9616 2001.09.11 21 S10E44 0360 FSO beta-gamma 9617 2001.09.12 6 N11E43 0070 DAO 9618 2001.09.13 7 S22W40 0030 DSO 9619 2001.09.13 6 N16E08 0020 CAO Total number of sunspots: 136 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) 2001.09 224.4 (1) 97.8 (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]