Solar Terrestrial Activity Report [Image] Last update October 18, 2002 at 03:05 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update 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 slightly active on October 17. Solar wind speed ranged between 491 and 713 km/sec under the influence of a high speed coronal stream. Solar flare activity was low. Solar flux was 178.9, the planetary A index was 11 (S.T.A.R. Ap - based on the mean of three hour ap indices: 12.0). Three hour interval K indices: 43223333 (planetary), 33122333 (Boulder). The background x-ray flux is at the class B8 level. At midnight there were 11 spotted regions on the visible disk, 2 of which has not yet been numbered. A total of 10 C class events were recorded during the day. Region 10140 rotated quietly out of view at the southwest limb. Region 10144 decayed and rotated quietly over the northwest limb. Region 10145 was quiet and stable. Region 10148 was quiet and stable. Region 10149 decayed slowly losing penumbral area in both the leading and trailing spot section. Several spots disappeared. Flare: C3.0 long duration event at 18:05 UTC. Region 10151 reemerged with a small spot. Region 10154 decayed losing most of its spots. The region could soon become spotless. Region 10157 decayed and was spotless again by midnight. Region 10158 was quiet and stable. Please observe that SEC has included the spots of S03 (see below) in this region. Region 10159 developed slowly as the large penumbra stretched longitudinally. Flare: C2.0 at 14:37 UTC. Region 10160 decayed slowly as the negative and positive polarity areas drifted further apart. Most of the intermediate spots disappeared. Region 10161 decayed and was spotless by late evening. New region 10162 rotated into view at the northeast limb. What could be trailing spots (or possibly another region) are becoming visible early on Oct.18. Flare: C2.2 at 22:21 UTC. Spotted regions which have not yet been numbered: 1. [S01] A new region emerged on October 14 just north of region 10149. The region developed slowly on October 15, then decayed on October 16 and 17. Location at midnight: N19W33. 2. [S03] A new region emerged in the southeast quadrant northeast of region 10158 on October 15. The region has been developing slowly and currently has mixed polarities. Location at midnight: S04E11. Flares: C2.6 at 03:58 and C2.3 at 11:44 UTC. Coronal mass ejections (CMEs) October 15: A large filament/prominence in the southern hemisphere lifted off. Activity began as early as 21:36 UTC on October 14 with the most noticeable activity occurring across the central meridian at latitudes below S25 during early afternoon on October 15. A partial halo CME was observed in LASCO images. The main part of the CME is not geoeffective, however, there is a chance that the northern flank could reach Earth on October 18. October 16-17: No obviously geoeffective CMEs were observed. Coronal holes A small coronal hole in the southern hemisphere was in a geoeffective position on October 16 and could cause a minor increase in geomagnetic activity on October 19. Another coronal hole in the southern hemisphere could rotate into a geoeffective position on October 23. Forecast The geomagnetic field is expected to be quiet to active on October 18 due to a coronal stream and a possible CME passage. 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) 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 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 10140 2002.10.04 1 S08W91 0040 HAX 10144 2002.10.07 1 N11W91 0030 HSX 10145 2002.10.08 1 1 N12W44 0070 HSX 10146 2002.10.09 S09W83 plage 10147 2002.10.09 S03W66 plage 10148 2002.10.09 1 1 S20W35 0020 HSX SEC spot count includes spots in region S01. The southern and 10149 2002.10.09 29 19 N14W33 0400 EAI northern spot sections appear to be 2 separate bipolar regions, each without intermixed polarities. 10151 2002.10.09 1 S14W57 0010 AXX 10153 2002.10.10 S05W44 plage 10154 2002.10.10 10 7 S12W18 0020 CSO classification ESO at midnight 10156 2002.10.11 N09W69 plage 10157 2002.10.12 2 N15W19 0010 CRO now spotless SEC spot count includes those of 10158 2002.10.12 16 1 S08E11 0140 DAO region S03. This is an HSX group. Position was S09E09 at midnight. 10159 2002.10.13 8 4 S11E18 0160 CAO 10160 2002.10.14 18 16 S20E15 0140 DAI 10161 2002.10.15 7 N06W26 0020 CSO now spotless classification EHO at 10162 2002.10.17 1 3 N25E76 0160 HHX midnight, area near 0250 then. S01 emerged on 4 N19W34 0020 CRO 2002.10.14 S02 emerged on S21E03 plage 2002.10.15 S03 emerged on 15 S04E11 0060 DAO beta-gamma 2002.10.15 S04 emerged on S08E20 plage 2002.10.15 Total spot count: 95 72 SSN: 215 182 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) 2002.04 189.8 120.4 (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) 2002.10 166.0 (1) 85.7 (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]