Solar Terrestrial Activity Report [Image] Last update September 4, 2002 at 04:15 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 development The geomagnetic field was quiet to unsettled on September 3. Solar wind speed ranged between 327 and 409 km/sec. An unexpected disturbance was observed arriving at SOHO just before 18h UTC. No obvious solar wind shock was observed as there was no abrupt increase in solar wind speed. Solar wind density had been building slowly all day, something which usually occurs prior to the arrival of a coronal stream. The intensity of the disturbance does, however, indicate the presence of a slow moving CME. The interplanetary magnetic field has been strongly southwards since late on September 3. Solar flare activity was moderate. Solar flux was 171.4, the planetary A index was 10 (3-hour planetary K indices: 2213 3333, Boulder K indices: 1112 2233). Region 10087 rotated quietly over the southwest limb. Region 10090 was quiet and stable. Region 10094 decayed slowly and quietly. Region 10095 decayed slowly and lost a significant amount of penumbral area in the leading and central spot sections. Some growth was observed in the trailing spots. The region is fairly simple magnetically with no or only minor polarity intermixing. Occasional minor M class flares are possible. Region 10096 developed significantly in the trailing spot section as a negative polarity field emerged inside the positive polarity area. A minor M class flare is possible. Region 10097 developed slowly and was mostly quiet. Region 10098 was quiet and stable. Region 10099 decayed slowly and quietly. Region 10100 developed some new small trailing spots and was quiet. Region 10101 was quiet and stable, as was region 10102. New region 10103 rotated into view at the northeast limb. Fairly strong emissions at the northeast limb indicate that another region is about to rotate into view. Flares and CMEs A total of 7 C and 1 M class events was recorded on September 3. Region 10097 produced a C1.4 flare at 11:28 UTC. An M1.0 flare at 00:54 UTC was optically uncorrelated and is likely to have occurred beyond one of the limbs. No CME was observed after the event. The background x-ray flux is at the class B7 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be unsettled to minor storm on September 4 and quiet to active on September 5-6. 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 10087 2002.08.22 1 S08W86 0060 HAX 10089 2002.08.24 S16W70 plage 10090 2002.08.26 1 S05W67 0090 HSX area much too large, 0040 is more realistic 10091 2002.08.27 N06W54 plage 10092 2002.08.27 S19W87 plage 10093 2002.08.29 S16W52 plage 10094 2002.08.29 5 S18E01 0140 CHO area too large, 10095 2002.08.29 64 N08E11 0750 FKI appears to be between 0500 and 0600. 10096 2002.08.30 17 S14E25 0120 DSO beta-gamma wrong classification 10097 2002.08.31 19 N12W06 0070 DAO 10098 2002.08.31 3 S10E38 0040 AXX area close to 0020 10099 2002.09.01 14 S05W02 0080 DAO 10100 2002.09.01 8 S15E43 0160 DAO latitude should be S19. Too few spots 10101 2002.09.01 3 S03E44 0070 HAX position was N02E56 one day earlier. Typo? 10102 2002.09.02 2 N08E53 0040 HSX 10103 2002.09.03 9 N15E73 0130 DAI Total number of sunspots: 146 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) 2002.09 175.2 (1) 22.7 (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]