Solar Terrestrial Activity Report [Image] Last update September 29, 2000 at 02:15 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 active on September 28. Solar wind speed ranged between 398 and 570 km/sec, generally decreasing all day. Solar flare activity was low. Solar flux was 202.3, the planetary A index was 12 (3-hour K indices: 2423 4322, Boulder K indices: 2423 4321). Region 9167 was quiet and stable, the region is rotating off the visible disk. Region 9169 decayed fairly quickly and was mostly quiet. The region is still capable of producing isolated M flares. Region 9170 decayed and was quiet. Regions 9171 and 9172 were quiet and stable. Region 9173 developed slowly and could produce C and minor M class flares. Region 9174 decayed into spotless plage. Region 9175 was quiet and stable. Region 9176 developed slowly and may be capable of minor M class flaring. Region 9177 was quiet and stable. New region 9178 rotated into view at the southeast limb. Flares and CMEs A total of 5 C class events were recorded on September 28. Region 9169 produced a C1.9 flare at 03:36 UTC. Region 9173 generated a C4.4 flare at 20:46 and a C4.7/1F flare at 23:02 UTC. A filament eruption was observed to the south and east of region 9177 across the central meridian. The eruption began at 04:24 UTC as observed in LASCO EIT images. A weak full halo CME was observed associated with this event. The CME could impact Earth sometime between late on September 30 and noon on October 1 and cause unsettled to minor storm conditions. September 27: A large filament eruption began at 19:48 UTC in the southeast quadrant covering an area from near region 9173 to near the central meridian. A dense CME was observed off parts of the southeast and southwest limbs and the south pole, this CME was probably a partial halo CME and could affect the geomagnetic field on September 30 or October 1. The background x-ray flux is at the class C1 level. Coronal holes A small coronal hole near the equator will rotate into a geoeffective position on September 29 and could cause the geomagnetic field to become unsettled to active on October 2. Forecast The geomagnetic field is expected to be quiet to unsettled on September 29 and 30, possibly becoming active by the end of the second day. 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 no. Location at region numbered sunspots midnight Area Classification Comment 9167 20000916 2 N16W81 0010 CRO 9169 20000918 51 N12W58 0790 FKC 9170 20000921 10 S06W63 0080 FSO 9171 20000922 4 S13W09 0050 CSO 9172 20000924 3 N12E18 0050 CSO 9173 20000924 25 S12E25 0130 EAO 9174 20000926 S30W84 plage 9175 20000926 3 N22E44 0010 BXO 9176 20000927 9 S09E57 0250 DAO 9177 20000927 2 N29W11 0000 AXX 9178 20000928 2 S23E63 0030 CRO Total number of sunspots: 111 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 2000.09 181.4 (1) 147.6 (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]