Solar Terrestrial Activity Report [Image] Last update October 24, 2002 at 01:50 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 October 13, 2002)] Recent activity The geomagnetic field was quiet to unsettled on October 23. Solar wind speed ranged between 403 and 471 km/sec. A disturbance began to influence the geomagnetic field after noon. Solar wind density had been increasing slowly all day until noon. It is still too early to tell if this disturbance is coronal stream related or has another origin. Early on October 24 the interplanetary magnetic field has become stronger and swung moderately southwards. Solar flare activity was low. Solar flux was 163.6, the planetary A index was 10 (STAR Ap - based on the mean of three hour ap indices: 11.4). Three hour interval K indices: 22223333 (planetary), 22223423 (Boulder). The background x-ray flux is at the class B5 level. At midnight there were 5 spotted regions on the visible disk, 1 of which has not yet been numbered. A total of 5 C class events were recorded during the day. Region 10158 decayed further and could become spotless before rotating out of view early on October 25. Please observe that SEC has included the spots of S03 (see below) in this region. Region 10160 decayed and became spotless by the end of the day. Region 10162 continued to lose penumbral area in the easternmost spot section. The central trailing penumbrae added some area and separated slowly. The northernmost central penumbra has a weak magnetic delta structure. M class flares are possible. Flare: C3.5 long duration event peaking at 01:09 UTC. Region 10165 lost most of the small spots while the large penumbra was mainly unchanged. Flare: C3.2 long duration event peaking at 16:24 UTC. New region 10166 emerged in the southeast quadrant. No spots were visible at midnight. New region 10167 rotated into view at the northeast limb. Spotted regions which have not yet been numbered: 1. [S03] A region emerged in the southeast quadrant northeast of region 10158 on October 15. The region developed slowly until October 18. Slow decay was observed on October 19. On October 20 the region decayed quickly. Slow development was observed on October 21 and 22. No significant changes were noted on October 23. Location at midnight: S06W75. Flare: C6.6 long duration event peaking at 02:32 UTC. Coronal mass ejections (CMEs) October 21-23: No obviously geoeffective CMEs were observed. Coronal holes A large and well defined coronal hole in the southern hemisphere was in a geoeffective position on October 21-24. Forecast The geomagnetic field is expected to be unsettled to minor storm on October 24-26 due to a coronal stream. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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) Data for all numbered solar regions according to the Solar Region Summary provided by SEC/NOAA. Comments are my own, as is the STAR spot count (spots observed at or just prior to midnight) and data for regions not numbered by SEC or where SEC has observed no spots. Solar Date SEC STAR Location region numbered spot spot at AreaClassification Comment countcount midnight SEC spot count includes those of region S03. This is 10158 2002.10.12 4 2 S08W75 0110 DAO a CSO group. Position was S09W71 at midnight, area was 0030 then. 10159 2002.10.13 S15W59 plage now spotless, 10160 2002.10.14 5 S19W72 0060 DSO area was 0030 early in the day 10162 2002.10.17 41 48 N26E10 1120 FKI beta-gamma-delta 10163 2002.10.18 S21W75 plage 10164 2002.10.20 N11E12 plage 10165 2002.10.20 4 4 N20E31 0230 CAO 10166 2002.10.23 1 S06E08 0000 AXX now spotless 10167 2002.10.23 1 1 N18E75 0060 HAX S03 emerged on 3 S06W75 0060 DAO 2002.10.15 S06 emerged on N24W49 plage 2002.10.19 Total spot count: 56 58 SSN: 116 108 Monthly solar data Average Month solar International sunspot Smoothed sunspot flux at number number Earth 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) 2002.04 189.8 120.7 (109.7 predicted, -3.7) 2002.05 178.4 120.8 (105.9 predicted, -3.8) 2002.06 148.7 88.3 (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) 2002.10 168.3 (1) 115.5 (2) (84.6 predicted, -4.1) 1) Running average based on the daily 20:00 UT observed 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]