Solar Terrestrial Activity Report [Image] Last update September 14, 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 minor storm on September 13. Solar wind speed ranged between 354 and 423 km/sec. There appears to have been a weak solar wind shock at approximately 01:30 at SOHO. Early on September 14, at 01:07 UTC, another solar wind shock was observed, this time with an abrupt increase in solar wind speed from 380 to 450 km/sec. Initially the interplanetary magnetic field has been mostly northwards. The source of this CME impact is uncertain, it is a bit early for the full halo CME observed on September 11 to arrive. Solar flare activity was low. Solar flux was 239.7, the planetary A index was 18 (3-hour K indices: 3454 3331, Boulder K indices: 3443 3232). Region 9606 was quiet and is rotating over the southwest limb. Region 9607 decayed further and was quiet. Region 9608 decayed slowly and lost its magnetic delta configurations. A major flare is still possible. Region 9610 was mostly unchanged and could produce M class flares. Region 9612 was quiet and stable. Region 9616 was generally unchanged and could produce M class flares. Region 9617 was quiet and stable. New region 9618 emerged between regions 9608 and 9610. New region 9619 emerged in the northeast quadrant. Flares and CMEs A total of 9 C class events were observed on September 13. Region 9616 produced a C6.6 flare at 02:07 UTC. Region 9608 generated a C4.6 flare at 03:54 UTC. Region 9610 was the source of a C2.4 flare at 13:06, a C2.4 flare at 13:12 and a C7.0 flare at 16:02 UTC (with an associated weak type II radio sweep). An optically uncorrelated C5.8 flare was recorded at 19:51 UTC, again with an associated weak type II radio sweep. 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. Forecast The geomagnetic field is expected to be quiet to minor storm on September 14-15. 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 9603 2001.09.02 S08W81 plage 9605 2001.09.03 S19W84 plage 9606 2001.09.03 1 S17W79 0090 HAX 9607 2001.09.04 5 S16W51 0080 CAO 9608 2001.09.05 34 S25W33 0960 FKI beta-gamma 9610 2001.09.06 49 S13W18 0510 EAC beta-gamma 9612 2001.09.07 12 N19W40 0070 DAO 9614 2001.09.08 N15W86 plage 9615 2001.09.08 N11W03 plage 9616 2001.09.11 16 S10E55 0320 FAO beta-gamma 9617 2001.09.12 6 N11E56 0120 CAO 9618 2001.09.13 6 S21W26 0030 DSO 9619 2001.09.13 4 N17E21 0020 BXO Total number of sunspots: 133 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) 2001.09 223.5 (1) 90.6 (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]