Solar Terrestrial Activity Report [Image] Last update August 28, 2001 at 05:40 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update August 1, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update August 1, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update August 1, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update July 27, 2001)] Recent development The geomagnetic field was quiet to active on August 27. Solar wind speed ranged between 379 and 604 km/sec. A solar wind shock was observed at SOHO at 19:14 UTC with an abrupt increase in solar wind speed from 430 to 590 km/sec. The interplanetary magnetic field was significantly weaker than expected after the shock and was mostly northwards resulting in only a minor disturbance so far. Solar flare activity was moderate. Solar flux was 192.0, the planetary A index was 12 (3-hour K indices: 2311 3344, Boulder K indices: 2411 2344). Region 9580 rotated quietly off the visible disk. Region 9585 decayed further and was quiet. Region 9587 developed slowly and was quiet, the region is rotating over the west limb. Region 9590 was quiet and stable. Region 9591 was mostly unchanged within the main penumbra but displayed quite a bit of activity to the northwest and west of the large penumbra with spots emerging and disappearing. M class flares are likely and there is a fairly good chance of another X class flare. Region 9596 was quiet and stable. Region 9597 reemerged with several spots. New region 9598 emerged at the southwest limb. New region 9599 emerged near the southeast limb. New regions 9600 and 9601 rotated into view at the northeast limb, magnetograms suggest that these regions are actually one complex region capable of at least M class flaring. Flares and CMEs A total of 11 C and 1 M class events were observed on August 27. Region 9591 generated a C4.1 flare at 00:17, a C3.0 flare at 04:05, a C3.2 flare at 05:51, a C4.6 flare at 13:45, a C3.3 flare at 14:14, a C3.9 flare at 15:34, a C5.0 flare at 17:46 and a C6.6 flare at 22:44 UTC. Region 9600 was the source of an M1.9 flare at 06:38 UTC. The background x-ray flux is at the class C1-C2 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be unsettled to active on August 28. 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 region numbered sunspots at Area Classification Comment midnight 9580 2001.08.14 1 N23W94 0080 HSX 9582 2001.08.15 N27W87 plage 9584 2001.08.16 S12W89 plage 9585 2001.08.16 5 N13W71 0050 DSO 9587 2001.08.17 7 S09W78 0280 DAO 9590 2001.08.20 4 S29W14 0160 HSX 9591 2001.08.21 40 S18E06 0720 FKI gamma-delta 9593 2001.08.23 N00W51 plage 9594 2001.08.24 N37W36 plage 9595 2001.08.24 N16W12 plage 9596 2001.08.25 2 N22E54 0170 HAX 9597 2001.08.26 8 N16E35 0050 DAO 9598 2001.08.27 1 S16W75 0030 AXX 9599 2001.08.27 2 S18E65 0010 BXO 9600 2001.08.27 1 N16E81 0060 HSX 9601 2001.08.27 1 N10E85 0060 HSX Total number of sunspots: 72 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.03 208.2 138.5 119.9 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.7 2000.08 163.0 130.5 118.6 (-1.1) 2000.09 182.1 109.7 116.3 (-2.3) 2000.10 167.4 99.4 114.5 (-1.8) 2000.11 178.8 106.8 112.8 (-1.7) 2000.12 173.6 104.4 112.1 (-0.7) 2001.01 166.6 95.6 108.8 (-3.3) 2001.02 146.6 80.6 (104.1 predicted, -4.7) 2001.03 177.7 113.5 (101.4 predicted, -2.7) 2001.04 177.7 108.2 (100.2 predicted, -1.2) 2001.05 147.1 97.3 (99.5 predicted, -0.7) 2001.06 173.0 134.0 (96.8 predicted, -2.7) 2001.07 131.3 82.2 (94.9 predicted, -1.9) 2001.08 158.0 (1) 139.9 (2) (95.5 predicted, +0.6) 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 25-40% 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. ------------------------------------------------------------------------ Do you know about the survey which will be held this Summer among the listeners of WWV and WWVH? There is information about this survey at 16 minutes past the hour on WWV and at 47 minutes past the hour on WWVH. If you want to participate send an email with your name and address. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]