Solar Terrestrial Activity Report [Image] Last update August 25, 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 August 7, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update August 7, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update August 7, 2002)] [Historical solar and geomagnetic data charts 1954-2002 (last update August 16, 2002)] Recent development The geomagnetic field was quiet to unsettled on August 24. Solar wind speed ranged between 323 and 402 km/sec. Solar flare activity was high. Solar flux was 195.6, the planetary A index was 11 (3-hour planetary K indices: 3222 3333, Boulder K indices: 3112 3212). Region 10069 rotated fully out of view very early in the day. Region 10079 rotated out of view early on Aug.25. Region 10083 decayed slowly except for the leading penumbra which developed slowly. There is still a weak magnetic delta structure within this penumbra. An M class flare is possible. Region 10084 decayed and lost of the small spots north of the main penumbra. Region 10085 decayed losing most of the spots outside of the large penumbra. The trailing positive polarity area, which had been close to the eastern edge of the main penumbra, drifted slowly away. Region 10086 was spotless all day according to all sources with the exception of SEC/NOAA which somehow managed to observe 6 spots. Region 10087 was mostly unchanged and is capable of producing occasional M class flares. Region 10088 developed slowly and quietly. New region 10089 emerged near the southeast limb, but has already decayed and could be spotless early on August 25. Flares and CMEs A total of 5 C, 2 M and 1 X class events was recorded on August 24. Region 10069, just behind the southwest limb, was the source of a long duration X3.1/1F proton event peaking at 01:12 UTC on August 24. A wide and large partial halo CME was observed after this event, the CME is not likely to be geoeffective. Region 10087 produced an M1.8/1N long duration event peaking at 05:46 UTC. A moderate type IV radio sweep was recorded and there appears to have been a CME off of the southeast limb. An optically uncorrelated M1.5 flare was recorded at 11:28 UTC. Region 10079 was the source of a C4.6 flare at 15:12 UTC, while region 10083 managed a C6.0 flare at 18:42 UTC. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on August 25-26. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very 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 Location region numbered no. at Area Classification Comment sunspots midnight 10069 2002.08.11 2 S08W95 0120 HKX 10076 2002.08.12 N13W81 plage 10077 2002.08.13 S18W82 plage 10079 2002.08.14 2 S22W82 0110 HAX 10080 2002.08.14 N14W58 plage 10081 2002.08.16 N18W44 plage 10082 2002.08.17 N20W85 plage 10083 2002.08.17 25 S18W27 0170 EAO beta-gamma-delta 10084 2002.08.18 14 S16W12 0070 DAO 10085 2002.08.19 24 S09E03 0500 DKO too many spots 10086 2002.08.22 6 S26E02 0010 BXO actually spotless! 10087 2002.08.22 19 S07E47 0330 DKI 10088 2002.08.23 16 S22W41 0120 DAI 10089 2002.08.24 1 S16E62 0010 AXX now spotless? Total number of sunspots: 109 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 2001.07 131.3 81.8 111.7 (+1.9) 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 (114.0 predicted, -0.5) 2002.03 179.5 98.4 (110.3 predicted, -3.7) 2002.04 189.8 120.4 (104.5 predicted, -5.8) 2002.05 178.4 120.8 (100.0 predicted, -4.5) 2002.06 148.7 88.5 (95.5 predicted, -4.5) 2002.07 173.5 99.9 (90.6 predicted, -4.9) 2002.08 187.6 (1) 162.3 (2) (86.6 predicted, -4.0) 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 25-45% 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]