Solar Terrestrial Activity Report [Image] Last update August 31, 2001 at 03:55 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 30. Solar wind speed ranged between 408 and 529 km/sec. A weak solar wind shock was observed at SOHO at 13:26 UTC with a sudden increase in solar wind speed from 440 to 510 km/sec. The disturbance that followed lasted only a few hours. Solar flare activity was moderate. Solar flux was 199.2, the planetary A index was 13 (3-hour K indices: 2233 3432, Boulder K indices: 2234 4432). Region 9590 was quiet and stable. Region 9591 decayed slowly but is still complex and capable of producing a major flare. Region 9596 was quiet and stable. Region 9597 decayed and was spotless early in the day. Region 9599 developed slowly and had a magnetic delta configuration early in the afternoon. This delta appeared to be gone by midnight reducing the chance of an M class flare from the region. Regions 9600 and 9601 were finally classified as one region, region 9601. This complex region is likely to continue to produce M class flares, and there is a chance of the region generating a major flare and possibly a particle event. Flares and CMEs A total of 8 C and 2 M class events were observed on August 30. Region 9601 produced a C3.3 flare at 00:59, a C5.4 flare at 01:39 and an impulsive M3.0/1N flare at 20:38 UTC. The latter flare was accompanied by a strong type II radio sweep. Region 9591 produced a C1.5 flare at 04:21, a C6.0 flare at 06:52 and an M1.5/2N flare at 17:57 UTC. Several CMEs were observed during the day. The background x-ray flux is at the class B9-C1 level. Coronal holes A fairly small coronal hole in the southern hemisphere near the equator was in a geoeffective position on August 29.. Forecast The geomagnetic field is expected to be quiet to unsettled on August 31 and quiet to active on September 1-2 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) Solar Date Actual Location region numbered no. at Area Classification Comment sunspots midnight 9590 2001.08.20 2 S30W56 0130 HAX 9591 2001.08.21 25 S20W33 0490 EKI beta-gamma-delta 9594 2001.08.24 N37W75 plage 9595 2001.08.24 N15W57 plage 9596 2001.08.25 1 N22E14 0190 HSX 9597 2001.08.26 3 N19W02 0010 BXO now spotless 9599 2001.08.27 19 S18E24 0220 DAO 9601 2001.08.27 28 N14E49 0700 FKI beta-gamma-delta Total number of sunspots: 78 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) 2001.08 162.0 (1) 154.8 (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. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]