Solar Terrestrial Activity Report [Image] Last update August 27, 2001 at 04:05 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update 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 unsettled on August 26. Solar wind speed ranged between 348 and 441 km/sec. Solar flare activity was moderate. Solar flux was 189.9, the planetary A index was 12 (3-hour K indices: 3133 3333, Boulder K indices: 2232 3334). Region 9580 was quiet and stable and will rotate off the visible disk today. Region 9585 decayed further and was quiet. Region 9587 developed further but seems to have become more stable. C flares and minor M class flares are possible. Region 9590 was quiet and stable. Region 9591 lost the magnetic delta within the leading spots section but still has a strong delta within the main penumbra. M class flares are likely and there is a fairly good chance of another X class flare. Region 9596 was quiet and stable. New region 9597 emerged briefly in the northeast quadrant, no spots were observed late in the day. An interesting region is about to rotate into view at the northeast limb. Flares and CMEs A total of 7 C and 1 M class events were observed on August 26. Region 9587 produced a C2.5 flare at 01:14 UTC. Region 9591 generated a C2.2 flare at 06:11, a C3.4 flare at 09:20, a C6.1 flare at 10:07, a C4.0 flare at 14:13, a C2.4 flare at 20:15 and a C5.7 flare at 21:00 UTC. A long duration M1.3 event peaked at 13:06 and had its origin just behind the northeast limb. August 25: Region 9591 produced a major X5.3/3B long duration event peaking at 16:45 (with associated moderately strong type II and IV radio sweeps and a fast and large full halo CME). The CME will likely impact Earth on August 27 and cause active to severe storm conditions. The background x-ray flux is at the class C1 level. Coronal holes A well defined coronal hole in the southern hemisphere was in a geoeffective position on August 23-24. Forecast The geomagnetic field is expected to be quiet to major storm on August 27, possibly with severe storm intervals. The possible presence of a coronal stream at the time of the arrival of the CME (associated with the X flare on August 25) could prevent the geomagnetic storm from reaching severe storm levels. 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) Solar Date Actual Location region numbered no. at Area Classification Comment sunspots midnight 9580 2001.08.14 1 N23W82 0080 HSX 9582 2001.08.15 N27W74 plage 9584 2001.08.16 S12W76 plage 9585 2001.08.16 7 N12W58 0050 DAO 9587 2001.08.17 12 S10W64 0210 DAO 9590 2001.08.20 3 S29W02 0180 HAX 9591 2001.08.21 43 S19E18 0740 FKI beta-gamma-delta 9593 2001.08.23 N00W38 plage 9594 2001.08.24 N37W23 plage 9595 2001.08.24 N16E01 plage 9596 2001.08.25 1 N22E67 0130 HSX 9597 2001.08.26 2 N17E48 0010 BXO Total number of sunspots: 69 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) 2001.08 156.7 (1) 134.0 (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]