Solar Terrestrial Activity Report [Image] Last update September 22, 2000 at 05:00 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 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update September 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update September 2, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update August 10, 2000)] Recent development The geomagnetic field was quiet to unsettled on September 21. Solar wind speed ranged between 430 and 522 km/sec. Solar flare activity was low. Solar flux was 225.1, the planetary A index was 9 (3-hour K indices: 2223 3322, Boulder K indices: 1313 2222). Region 9165 decayed quickly and was quiet, the region will rotate over the west limb today. Region 9166 was mostly unchanged and quiet, the region could produce a major flare. Region 9167 decayed slowly and was quiet. Minor M class flaring is possible. Region 9169 added several new spots and is still a very large and complex region capable of producing major flares, including very energetic X flares, at any time. The region has, however, been remarkably quiet over the last few days. New region 9170 emerged in the southeast quadrant. Flares and CMEs A total of 6 C class events were recorded on September 21. Region 9169 produced a C3.0 flare at 02:05 UTC. The remainder of the flares were optically unaccounted. September 20: Region 9165 generated a major M5.1/1N flare at 08:26 UTC. A weak type II sweep was associated with this event and a CME was observed in LASCO C3 several hours after the event. The CME seemed to be a partial halo one and could cause increased geomagnetic activity on September 22. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on September 22. 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) Solar Date Actual Location region numbered no. at Area Classification Comment sunspots midnight 9161 20000911 N08W84 plage 9165 20000913 3 N16W80 0030 HRX 9166 20000914 49 S12W16 0760 EKO beta-gamma 9167 20000916 20 N12E17 0160 ESO 9168 20000917 N09W46 plage 9169 20000918 68 N09E32 1910 FKC beta-gamma-delta 9170 20000921 8 S07E28 0040 CAO Total number of sunspots: 148 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.07 165.6 113.5 94.3 (+1.2) 1999.08 170.7 93.7 97.5 (+3.2) 1999.09 135.7 71.5 102.3 (+4.8) 1999.10 164.8 116.7 107.8 (+5.5) 1999.11 191.5 133.2 110.9 (+3.1) 1999.12 169.8 84.6 111.0 (+0.1) 2000.01 158.1 90.1 112.8 (+1.8) 2000.02 174.1 112.9 116.6 (+3.8) 2000.03 208.2 138.5 (118.7 predicted, +2.1) 2000.04 184.2 125.3 (119.6 predicted, +0.9) 2000.05 184.9 120.8 (120.4 predicted, +0.8) 2000.06 179.8 124.9 (122.0 predicted, +1.6) 2000.07 202.3 169.1 (124.1 predicted, +2.1) 2000.08 163.0 130.6 2000.09 168.6 (1) 93.9 (2) 1) Running average based on the daily 20:00 UTC solar flux value at 2800 MHz. 2) Unofficial, accumulated value. The official value 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 in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]