Solar Terrestrial Activity Report [Image] Last update October 8, 2002 at 03:45 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update October 2, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update October, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update October 2, 2002)] [Historical solar and geomagnetic data charts 1954-2002 (last update August 16, 2002)] Recent activity The geomagnetic field was unsettled to major storm on October 7. Solar wind speed ranged between 341 and 483 km/sec. The interplanetary magnetic field swung was moderately to strongly southwards most of the day. After 10h UTC the IMF was dominated by a coronal stream. Solar flare activity was low. Solar flux was 163.8, the planetary A index was 39 (S.T.A.R. calculated average value based on three hour Ap indices: 39.1). Three hour interval K indices: 35645443 (planetary), 35635333 (Boulder). The background x-ray flux is at the class B6 level. Region 10137 decayed slowly and quietly. At the current rate of decay all trailing spots will disappear today. Region 10139 developed further with most of the development occurring in the trailing negative polarity spots. There is at least one magnetic delta structure. With the penumbral areas of the central and trailing spots joining there is a strengthening delta along the inversion line. Another and weaker delta appears to be forming in one of the leading penumbrae as positive polarity flux is emerging at the eastern edge of a negative polarity spot. Although the region was quiet on Oct.7, there is a possibility of a major flare. Region 10140 was mostly quiet and stable. Flare: C1.4 at 15:56 UTC. Region 10141 decayed slowly in the trailing spot section while slow development was observed in the leading spots. Region 10142 was quiet and stable. New region 10143 emerged in the southwest quadrant. New region 10144 emerged in the northeast quadrant and is developing at a moderate pace. The leading spots of region 10140 still appear to be a separate region. A long duration C3.1 event peaked at 16:57 UTC and had its source behind the northeast limb. A C1.8 flare at 21:56 UTC had an origin behind the northwest limb. Coronal mass ejections (CMEs) October 6-7: No obviously geoeffective CMEs were observed during the period. Coronal holes A moderately large coronal hole in the southern hemisphere was in a geoeffective position on October 4-6. Forecast The geomagnetic field is expected to be unsettled to active (with a chance of an isolated minor storm interval) on October 8 due to a coronal stream and quiet to unsettled on October 9-11. 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) SEC Solar Date number Location region numbered of at Area Classification Comment spots midnight 10137 2002.09.29 8 S19W60 0200 DAO area near 0110 at midnight beta-gamma-delta 10139 2002.10.02 40 N11E06 0600 EKI classification EKC at midnight The leading 4 spots make up a separate CSO region (located at 10140 2002.10.04 6 S08E36 0200 DSO S08E33 at midnight). The large trailing penumbra is a HSX region (location S08E42 at midnight) classification DAO at 10141 2002.10.05 8 S08W08 0050 DSO midnight with an area of 0070 10142 2002.10.05 1 N05E36 0020 HSX 5 spots observed at 10143 2002.10.07 2 S19W38 0010 HRX midnight, classification DAO then, area 0030 area at least 0060 at 10144 2002.10.07 8 N12E44 0020 CRO midnight, classification DAO ? emerged (4) S08E33 0020 CSO 2002.10.05 Total number of sunspots: 73 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 2001.09 233.2 150.7 114.1 (+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 98.4 113.4 (-1.3) 2002.04 189.8 120.4 (109.7 predicted, -3.7) 2002.05 178.4 120.8 (105.9 predicted, -3.8) 2002.06 148.7 88.5 (101.4 predicted, -4.5) 2002.07 173.5 99.9 (96.5 predicted, -4.9) 2002.08 183.6 116.4 (92.5 predicted, -4.0) 2002.09 175.8 109.3 (88.7 predicted, -3.8) 2002.10 151.4 (1) 26.0 (2) (84.6 predicted, -4.1) 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]