Solar Terrestrial Activity Report [Image] Last update August 24, 2002 at 04:05 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 23. Solar wind speed ranged between 359 and 437 km/sec. Solar flare activity was high. Solar flux was 215.9 (the measurement at 17h UTC was used as the 20h UTC value was enhanced by flare activity), the planetary A index was 11 (3-hour planetary K indices: 2322 3333, Boulder K indices: 3121 2333). Region 10069 decayed further as it rotated over the southwest limb. Another X class flare may be possible while the region is just behind the southwest limb. Region 10079 decayed slowly and quietly and will rotate over the southwest limb tomorrow Aug.25. Region 10080 decayed further and was spotless by late evening. This left the entire northern hemisphere spotless. Region 10083 decayed slowly towards the end of the day. Early in the day a magnetic delta structure had developed in the central parts of the region. Another M class flare may be possible. Region 10084 was mostly unchanged and quiet. Region 10085 was mostly unchanged and remains capable of producing occasional M class flares. Region 10086 decayed and became spotless during the morning. Region 10087 was mostly unchanged and is capable of producing M class flares. New region 10088 emerged very quickly in the southwest quadrant, west southwest of region 10083. Although the region is not magnetically complex at this time, further development could quickly change that. Flares and CMEs A total of 8 C and 5 class events was recorded on August 23. Region 10069 produced a C5.0 flare at 00:46, a C9.4 flare at 04:20, an M1.5/1N long duration event peaking at 09:46, a C8.1 flare at 11:46 and an M1.2 flare at 12:00 UTC. Region 10085 generated an M1.7 flare at 05:49 UTC. This event triggered a minor filament eruption in a filament channel stretching from region 10085 across the equator and central meridian into the northwest quadrant. No obvious CME was observed, although a moderate type II sweep was recorded. Region 10087 was the source of a C8.6 flare at 06:25 and an M1.5/2F flare at 13:14 UTC. Region 10083 produced an M1.4/2F long duration event peaking at 20:21 UTC. Lots of CMEs were observed on August 23, at one time four different CMEs could be seen. Most of the CMEs appeared to have their origin near or behind the east and west limbs. Region 10069, just behind the southwest limb, was the source of a long duration X3.1 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. The above 100 MeV proton flux appears to have peaked near 29 pfu while the above 50 MeV flux peaked near 75 pfu. The above 10 MeV proton flux is still increasing and is currently approaching the 250 pfu mark. August 22: Region 10069 was the source of a major M5.4/2B flare at 01:57 UTC. A small proton event began soon after. A weak type IV and a moderate type II radio sweep was reported. LASCO C3 images indicate a partial halo CME was produced. The CME will not impact Earth directly, however, a minor geomagnetic disturbance is likely on August 24. The flare caused a filament eruption in region 10077 as well. The background x-ray flux is at the class C2 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 24-25. 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 the region was at N10W84 one day earlier. No spots could 10067 2002.08.10 3 N11W92 0070 CAO be observed very early in the day. The region should not have been included in the SEC/NOAA summary 10069 2002.08.11 17 S08W85 0830 CKO beta-gamma 10076 2002.08.12 N13W68 plage 10077 2002.08.13 S18W69 plage 10079 2002.08.14 9 S21W65 0160 DAO SEC/NOAA correctly reported a 3 spot HSX group with an area of 10080 2002.08.14 1 N14W45 0030 HAX 0020 the day before. The region decayed further and is now spotless. Classification should have been HRX and area 0010. 10081 2002.08.16 N18W31 plage 10082 2002.08.17 N20W72 plage 10083 2002.08.17 21 S19W15 0170 FAO beta-gamma-delta 10084 2002.08.18 19 S15E00 0090 DAO 10085 2002.08.19 19 S09E16 0520 DKO beta-gamma 10086 2002.08.22 2 S23E17 0010 HRX now spotless 10087 2002.08.22 10 S07E60 0450 DKO area too large, 0300 is a better estimate area too small, was near 10088 2002.08.23 6 S22W28 0040 CRO 0150 at midnight, classification DAO Total number of sunspots: 107 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) 155.8 (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]