Solar Terrestrial Activity Report [Image] Last update August 26, 2002 at 03:55 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 25. Solar wind speed ranged between 282 and 371 km/sec. Solar flare activity was moderate. Solar flux was 178.6, the planetary A index was 9 (3-hour planetary K indices: 2222 2333, Boulder K indices: 2221 3213). Region 10080 reemerged quickly before noon but was decaying again by late afternoon. Region 10083 lost nearly all remaining spots outside of the largest penumbra. This penumbra still has a magnetic delta structure. Further M class flares are possible as long as this delta exists. Region 10084 was mostly unchanged and quiet. Region 10085 developed slowly and the large penumbra was less symmetrical than one day earlier. An M class flare is possible. Region 10087 has developed a magnetic delta structure in the eastern part of the main penumbra. M class flares are possible. Region 10088 decayed slowly and quietly. Region 10089 decayed slowly and was spotless by early evening. SEC/NOAA somehow managed not to notice a new slowly developing region near the southeast limb and just south of the equator. Flares and CMEs A total of 4 C and 2 M class events was recorded on August 25. Region 10080 produced a C1.4 flare at 16:13 UTC. Region 10083 generated an M1.1 flare at 18:53 and an M1.9 flare at 23:46 UTC. Region 10083 was the source of a long duration M1.9 event peaking at 01:00 on August 26, a fairly small CME off the west limb was associated with this event. At 23:48 UTC on August 25 a filament eruption was observed westwards of region 10087, no obvious CME was associated with this event. The background x-ray flux is at the class B9 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 26 and quiet to unsettled on August 27-28. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to 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 10080 2002.08.14 5 N14W70 0060 CSO 10081 2002.08.16 N18W57 plage 10083 2002.08.17 7 S17W41 0120 DAO beta-gamma-delta 10084 2002.08.18 6 S16W26 0070 DAO 10085 2002.08.19 19 S08W09 0520 DKO 10086 2002.08.22 S26W11 plage 10087 2002.08.22 15 S07E34 0410 DKI beta-gamma-delta 10088 2002.08.23 13 S23W54 0200 DAI 10089 2002.08.24 1 S16E47 0000 AXX now spotless Total number of sunspots: 66 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) 2002.08 187.2 (1) 166.6 (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]