Solar Terrestrial Activity Report [Image] Last update October 3, 2000 at 02:55 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update October 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update October 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update October 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 October 2. Solar wind speed ranged between 343 and 436 km/sec. A fairly weak coronal stream began to influence the geomagnetic field after 06h UTC. A minor solar wind shock was observed at ACE at 00:04 UTC on October 3. The total magnetic field of the interplanetary magnetic field strengthened and a stronger southerly swing was observed. Solar flare activity was moderate. Solar flux was 202.6, the planetary A index was 11 (3-hour K indices: 1222 3433, Boulder K indices: 1122 3433). Regions 9171 and 9172 were quiet and stable. Region 9173 developed slowly and could produce minor M class flares. Region 9176 became more complex and has M class flaring potential. Region 9177 developed slowly and could produce further minor M class flares. Region 9178 developed slowly and could produce minor M class flares. Region 9179 developed slowly and was quiet. Region 9180 was quiet and stable. New region 9181 rotated into view at the southeast limb. New region 9182 rotated into view at the southeast limb near the equator. Flares and CMEs A total of 9 C and 2 M class events were recorded on October 2. An optically uncorrelated M1.0 flare was recorded at 00:13 UTC. LASCO EIT images indicate that the source of the flare could have been region 9169, well behind the northwest limb. Region 9176 produced a C4.1 flare at 02:57, a C4.5 flare at 11:14 and a C8.4/1F flare at 20:04 UTC. Region 9177 generated a C4.4/1F flare at 05:36 and an M1.4/1N flare at 18:01 UTC. Region 9178 was the source of a C3.6 flare at 16:05 while region 9182 managed a C4.8 flare at 21:31 UTC. October 1: Region 9176 produced a C3.8/1F flare at 13:04 UTC. A weak type II sweep was observed in association with this event, and with the region only one day's rotation away from the central meridian, the coronal mass ejection will likely impact Earth between late on October 3 and noon on October 4. The background x-ray flux is at the class B7 level. Coronal holes No obvious coronal holes are currently approaching the central meridian. Forecast The geomagnetic field is expected to be unsettled to minor storm on October 3-4. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 no. Location at region numbered sunspots midnight Area Classification Comment 9171 20000922 1 S10W63 0010 HRX 9172 20000924 1 N15W34 0030 HSX 9173 20000924 20 S11W28 0310 EKI beta-gamma 9175 20000926 N22W07 plage 9176 20000927 26 S09E04 0270 FHI beta-gamma 9177 20000927 9 N31W54 0150 CAO beta-gamma 9178 20000928 18 S22E09 0230 DAI beta-gamma 9179 20000930 5 N36W17 0030 CRO 9180 20001001 1 S32W35 0020 HSX 9181 20001002 6 S32E65 0150 DAO 9182 20001002 3 S02E73 0060 CAO Total number of sunspots: 90 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 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) 2000.03 208.2 138.5 119.8 (+3.2) 2000.04 184.2 125.3 (121.7 predicted, +1.9) 2000.05 184.9 120.8 (122.5 predicted, +0.8) 2000.06 179.8 124.9 (124.1 predicted, +1.6) 2000.07 202.3 169.1 (126.2 predicted, +2.1) 2000.08 163.0 130.6 (124.8 predicted, -1.4) 2000.09 182.1 109.9 2000.10 202.1 (1) 11.2 (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]