Solar Terrestrial Activity Report [Image] Last update September 5, 2002 at 03:45 UTC. Minor update posted at 18:55 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update 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 unsettled to major storm on September 4. Solar wind speed ranged between 380 and 478 km/sec. The disturbance, which began on September 3, ended abruptly near 18h UTC. Solar flare activity was low. Solar flux was 171.3, the planetary A index was 42 (3-hour planetary K indices: 4656 5443, Boulder K indices: 4645 5433). Region 10090 decayed and is rotating quietly over the southwest limb. Region 10094 was mostly quiet and stable. Region 10095 decayed slowly losing penumbral area in the leading and central spot sections. A minor M class flare is possible. Region 10096 developed slowly adding penumbral area in most parts of the region. Early in the day a magnetic delta appeared to be forming in the central part. Towards the end of the day the central negative polarity area, which earlier had been completely surrounded by a positive polarity area, bordered the positive polarity area only in its southern part. A minor M class flare is possible. Region 10097 increased its penumbral area and lost some of its smaller spots. Region 10098 decayed and had only a single small spot left by the end of the day. The region will likely become spotless early today. Region 10099 decayed slowly and quietly. Region 10100 decayed slowly and was quiet. Regions 10101 and 10102 both decayed and could become spotless today or tomorrow. Region 10103 developed slowly and quietly. SEC/NOAA failed to notice a region which emerged near the northwest limb on September 3 with several spots. The region decayed on September 4 and appeared to be spotless late in the day. Comment added at 18:55 UTC on September 5: A long duration eruption C5 eruption peaking at 17:10 UTC had its origin near region 10102. A CME was associated with this event and early LASCO images indicate that this was at least a partial halo CME. The CME could be geoeffective and reach Earth on September 8. Flares and CMEs A total of 13 C class events was recorded on September 4. Region 10095 produced a C1.5 flare at 05:47, a C1.6 flare at 15:31 and a C1.2 flare at 17:03 UTC. Region 10096 generated a C2.3 flare at 06:28, a C1.6 flare at 10:33 and a C2.5 flare at 14:54 UTC. Region 10094 was the source of a C1.2 flare at 14:17 UTC. The background x-ray flux is at the class B6 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on September 5 and quiet to unsettled on September 6-7. 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 no. Location at region numbered sunspots midnight Area Classification Comment 10089 2002.08.24 S16W83 plage 10090 2002.08.26 1 S04W80 0040 HSX 10091 2002.08.27 N06W67 plage 10093 2002.08.29 S16W65 plage 10094 2002.08.29 2 S18W14 0130 CSO 10095 2002.08.29 39 N08W03 0550 FKC 10096 2002.08.30 20 S16E13 0160 DAI beta-gamma 10097 2002.08.31 15 N13W19 0080 DAO 10098 2002.08.31 4 S10E25 0020 CAO 10099 2002.09.01 5 S04W15 0040 CSO 10100 2002.09.01 7 S20E31 0190 CAO 10101 2002.09.01 3 N02E30 0040 CAO 10102 2002.09.02 1 N08E39 0020 HAX 10103 2002.09.03 8 N14E60 0110 DAO Total number of sunspots: 105 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) 2002.09 174.3 (1) 29.8 (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]