Solar Terrestrial Activity Report [Image] Last update September 25, 2002 at 04:25 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 3, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update September 3, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update September 3, 2002)] [Historical solar and geomagnetic data charts 1954-2002 (last update August 16, 2002)] Recent activity The geomagnetic field was quiet to slightly unsettled on September 24. Solar wind speed ranged between 338 and 444 km/sec. Solar flare activity was low. Solar flux was 157.9, the planetary A index was 6. K indices calculated for three hour intervals: 22122232 (planetary), 11212122 (Boulder). The background x-ray flux is at the class B6 level. Region 10117 gained a few trailing spots and was quiet. Region 10119 decayed further and is about to rotate out of view at the southwest limb. Flare: A C3.1 flare at 15:55 UTC. Region 10121 decayed and had only a tiny spot left by midnight. The region will likely become spotless today. Region 10122 was quiet and stable. Region 10123 decayed, only a single tiny spot was visible at the end of the day. The region will probably become spotless today. Region 10125 was quiet and stable. Region 10126 decayed and was spotless by midnight. Region 10127 was mostly unchanged and quiet. Region 10129 developed slowly and quietly. Region 10130 developed quickly and could soon become capable of producing at least C class flares. Region 10131 decayed and was spotless by early evening. Region 10132 developed slowly. The magnetic delta in the center of the region became stronger. M class flares are possible. Region 10133 developed slowly early in the day, then began to decay slowly. New region 10134 rotated into view at the northeast limb. Another new region has rotated into view at the northeast limb, just southeast of region 10134. A new small region has emerged in the northeast quadrant northwest of region 10130. Coronal mass ejections (CMEs) No CMEs of interest was observed September 22-24. Coronal holes A poorly defined coronal hole in the northern hemisphere was in a geoeffective position on September 22. A well placed coronal hole in the southern hemisphere will rotate into a geoeffective position on September 26-27. Forecast The geomagnetic field is expected to be quiet to unsettled on September 25-27, possibly with a few active intervals on Sept.25. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair. 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 10117 2002.09.15 1 S08W48 0160 HSX 4 spots observed at midnight. Classification: DSO 10119 2002.09.16 11 S13W76 0430 EKI 10120 2002.09.16 S19W49 plage 10121 2002.09.16 2 S12W42 0020 HAX 1 spot AXX group at midnight. 10122 2002.09.16 2 S16W32 0020 HSX 10123 2002.09.17 1 S17W67 0020 AXX 10125 2002.09.18 9 S07W07 0020 BXO 10126 2002.09.19 1 S22E10 0010 HRX now spotless 10127 2002.09.20 22 S13W35 0190 DAI 10128 2002.09.20 N10E10 plage 10129 2002.09.22 8 N26E26 0020 CSO 10130 2002.09.22 11 N06E25 0040 CSO area was near 0100 at midnight. Classification: DAO 10131 2002.09.22 3 S06E07 0010 BXO now spotless 10132 2002.09.22 19 N19W28 0390 DKI beta-delta 10133 2002.09.23 7 S25E05 0050 DAO reversed polarity 10134 2002.09.24 3 N11E79 0050 CAO Total number of sunspots: 100 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.8 2001.08 162.9 106.4 113.6 (+1.8) 2001.09 233.2 150.7 114.1 (+0.5) 2001.10 207.6 125.5 114.0 (-0.1) 2001.11 210.6 106.5 115.5 (+1.5) 2001.12 235.1 132.2 114.6 (-0.9) 2002.01 226.6 114.1 113.5 (-1.1) 2002.02 205.0 107.4 114.7 (+1.2) 2002.03 179.5 98.4 (113.2 predicted, -1.5) 2002.04 189.8 120.4 (108.7 predicted, -4.5) 2002.05 178.4 120.8 (104.2 predicted, -4.5) 2002.06 148.7 88.5 (99.7 predicted, -4.5) 2002.07 173.5 99.9 (94.9 predicted, -4.8) 2002.08 183.6 116.4 (90.8 predicted, -4.1) 2002.09 183.0 (1) 175.0 (2) (87.1 predicted, -3.7) 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 25-45% 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]