Solar Terrestrial Activity Report [Image] Last update September 24, 2002 at 04:20 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 on September 23. Solar wind speed ranged between 347 and 461 km/sec. Solar flare activity was low. Solar flux was 153.8, the planetary A index was 5. K indices calculated for three hour intervals: 22122221 (planetary), 21111110 (Boulder). The background x-ray flux is at the class B4 level. Region 10115 decayed and rotated quietly over the southwest limb. Region 10117 was quiet and stable. Region 10119 continued to decay quickly and lost penumbral area in all parts of the region. The region is currently fairly simple with no obvious intermixing of polarities. Region 10121 decayed slowly and quietly. Region 10122 decayed slowly and quietly. Region 10123 decayed slowly and quietly. Region 10125 developed slowly early in the day, then decayed and could soon become spotless. Region 10126 decayed slowly and quietly. Region 10127 developed slowly and was quiet. Region 10129 developed slowly adding a number of small spots. Region 10130 developed slowly and quietly. Region 10131 decayed and could soon become spotless. Region 10132 developed further and more than doubled its penumbral area. Development was quick in the trailing part of this compact region and slower in the leading part, and by noon the region had eclipsed region 10119 as the largest region on the visible disk. There is still a centrally located magnetic delta structure. M class flares are possible. New region 10133 emerged in the southeast quadrant on September 22 and developed slowly on Sept.23. This is a revered polarity region. Coronal mass ejections (CMEs) No CMEs of interest was observed on September 21-23. 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 23-25, 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 10115 2002.09.14 2 S05W85 0080 HAX 10117 2002.09.15 3 S10W34 0180 CSO 10118 2002.09.16 N13W79 plage 10119 2002.09.16 12 S14W59 0720 EKI area at midnight near 0300! classification DKO 10120 2002.09.16 S19W36 plage 10121 2002.09.16 3 S13W28 0030 HSX 10122 2002.09.16 1 S17W18 0030 HSX 10123 2002.09.17 1 S16W54 0030 HSX 10125 2002.09.18 2 S09E01 0010 AXX 10126 2002.09.19 2 S22E24 0010 AXX area was 0020 at midnight 10127 2002.09.20 15 S13W21 0170 DAO 10128 2002.09.20 N10E23 plage 9 spots observed, 10129 2002.09.22 1 N26E41 0010 AXX classification CSO at midnight. Area was 0030. 10130 2002.09.22 2 N06E37 0020 HSX 10131 2002.09.22 2 S06E21 0010 AXX beta-delta 10132 2002.09.22 16 N19W14 0230 DKO area near 0400 at midnight, classification DKC 10133 2002.09.23 7 S25E20 0070 DAO reversed polarity Total number of sunspots: 69 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) 2002.09 184.1 (1) 167.0 (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]