Solar Terrestrial Activity Report [Image] Last update September 1, 2001 at 04:45 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update September 1, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update September 1, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update September 1, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update July 27, 2001)] Recent development The geomagnetic field was unsettled to active on August 31. Solar wind speed ranged between 368 and 470 km/sec. Solar flare activity was moderate. Solar flux was 188.7, the planetary A index was 16 (3-hour K indices: 3344 3433, Boulder K indices: 3334 3423). Region 9590 decayed quietly, the region will rotate out of view on September 2. Region 9591 decayed further but still has a large penumbra containing spots of opposite polarities. A major flare is possible as long as this configuration persists. Region 9596 was quiet and stable. Region 9599 decayed slowly and quietly. Region 9601 is a complex region with mixed magnetic polarities occurring through most of the region. Some decay has been observed in parts of the region but new spots have emerged in other places. A major flare is possible over the next couple of days. Flares and CMEs A total of 4 C and 2 M class events were observed on August 31. Region 9601 produced an impulsive M1.6 flare at 10:42 (with an associated moderate type II radio sweep but no obvious earth directed CME), a C4.8/1F flare at 11:40, a C1.7 flare at 15:09, a C2.0 flare at 15:40 and a C8.6/1N flare at 21:25 UTC. The region was likely the source of an impulsive M2.9 flare at 22:42 UTC as well, but I haven't been able to confirm this as SOHO EIT images are unavailable because of a CCD bakeout. The background x-ray flux is at the class B8 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 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 SEC/NOAA 9590 2001.08.20 2 S29W68 0060 HAX reported area as 0150, way too high! 9591 2001.08.21 17 S20W39 0400 FKO beta-gamma-delta 9594 2001.08.24 N37W88 plage Error from SEC/NOAA, region 9595 2001.08.24 3 N17W70 0030 CRO has been spotless for quite some time 9596 2001.08.25 1 N22E01 0150 HSX 9597 2001.08.26 N19W15 plage 9599 2001.08.27 14 S18E11 0190 DAO 9601 2001.08.27 45 N14E32 0760 FKC beta-gamma-delta Actual number of spots should have been 89 and the SSN 139. Notice that SEC/NOAA reports Total number of the SSN as 142, indicating that someone knew sunspots: 92 there were only 5 spotted regions but forgot to remove the spots mistakenly included from region 9595!! 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 (-4.7) 2001.03 177.7 113.5 (102.2 predicted, -1.9) 2001.04 177.7 108.2 (101.2 predicted, -1.0) 2001.05 147.1 97.3 (100.1 predicted, -1.1) 2001.06 173.0 134.0 (97.3 predicted, -2.8) 2001.07 131.3 82.2 (95.5 predicted, -1.8) 2001.08 162.9 106.8 (96.0 predicted, +0.5) 2001.09 (1) (2) (95.0 predicted, -1.0) 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]