Solar Terrestrial Activity Report [Image] Last update September 26, 2002 at 04:45 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 25. Solar wind speed ranged between 313 and 420 km/sec. Solar flare activity was low. Solar flux was 153.4, the planetary A index was 6 (this value is too low based on three hour Ap indices, the average is actually 7.6). K indices calculated for three hour intervals: 22112232 (planetary), 11013212 (Boulder). The background x-ray flux is at the class B8 level. Region 10117 decayed slowly and quietly. Region 10119 decayed slowly as it rotated out of view at the southwest limb. Region 10121 decayed and was spotless by early morning. Region 10122 developed slowly as a leading positive polarity field emerged. The region currently has reversed polarities. Region 10123 decayed and was spotless by early morning. Region 10125 was quiet and stable. Region 10127 decayed in the trailing section and developed in the leading spot section. Region 10129 developed slowly and quietly. Region 10130 developed further and more than doubled its penumbral area. C class flares are possible. Region 10131 was spotless all day in all available images. Region 10132 lost some penumbral area, however, a new positive polarity area emerged in the northeastern part of the region. This new flux is about to split the trailing negative polarity area and has created a second delta structure. Activity in the region is increasing and an M class flare is likely today. Region 10133 decayed slowly and quietly. Region 10134 developed slowly. It should be noted that the trailing southeastern penumbra is a separate region. Coronal mass ejections (CMEs) No CMEs of interest was observed September 23-25. Coronal holes 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 26-28 and quiet to active on September 29-30 due to a coronal stream. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair to good. 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 4 S09W60 0190 DSO 3 spots observed at midnight, classification CSO 10119 2002.09.16 12 S13W88 0420 EKI 10120 2002.09.16 S19W62 plage 10121 2002.09.16 1 S12W55 0020 HSX actually spotless 6 spots observed at midnight, 10122 2002.09.16 1 S18W46 0030 HSX classification CSO, reversed polarity 10123 2002.09.17 1 S16W80 0020 HSX actually spotless 10125 2002.09.18 5 S07W24 0020 CSO 10126 2002.09.19 S22W03 plage 10127 2002.09.20 19 S14W47 0210 DAI 10128 2002.09.20 N10W03 plage 10129 2002.09.22 8 N26E12 0030 DSO 10130 2002.09.22 10 N06E10 0120 DAO area was near 0250 at midnight. 10131 2002.09.22 4 S06W09 0010 BXO actually spotless 10132 2002.09.22 20 N19W41 0400 DKC beta-delta 10133 2002.09.23 8 S25W07 0050 DAO reversed polarity, area 0030 at midnight location N12E64 10134 2002.09.24 7 N10E64 0150 DAO two separate regions, the second region located at N08E67 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) 2002.09 181.8 (1) 182.7 (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]