Solar Terrestrial Activity Report [Image] Last update January 24, 2001 at 04:00 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update January 2, 2001) - Has cycle 23 peaked?] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update January 2, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update January 2, 2001)] [Historical solar and geomagnetic data charts 1954-2000 (last update January 18, 2001)] Recent development The geomagnetic field was quiet to active on January 23. Solar wind speed ranged between 393 and 586 km/sec. A moderate solar wind shock was observed at 10:08 UTC at ACE. Solar wind speed abruptly increased from 420 to 570 km/sec. The interplanetary magnetic field gradually swung southwards but became weaker towards the end of the day. Solar flare activity was low. Solar flux was 167.1, the planetary A index was 11 (3-hour K indices: 1103 3343, Boulder K indices: 2103 3443). Region 9311 developed slowly and became more unstable. Further C class flaring is likely and there is a fair chance for a minor M class flare. Region 9313 lost some of its areal coverage and appears to be slowly decaying. The region could still produce a minor M class flare. Region 9315 reemerged with a single spot, the region is spotless again early on January 24. Region 9316 was quiet and stable, C class flaring is possible. Region 9319 was quiet and stable, as was region 9320, both regions could soon become spotless. Region 9321 developed slowly and could produce C flares and perhaps a minor M class flare. New regions 9322 and 9323 emerged in the southeast quadrant near the central meridian. New region 9324 emerged in the northeast quadrant. Flares and CMEs A total of 3 C class events were recorded on January 23. Region 9311 produced a long duration C4.3 event peaking at 20:44 UTC. This region was also the source of a C9.2 flare early on January 24. The background x-ray flux is at the class B7 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on January 24-26 with a chance of a few isolated active intervals on the first 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 9310 2001.01.14 N27W67 plage 9311 2001.01.15 11 N06W62 0140 DAO beta-gamma 9312 2001.01.16 N06W32 plage 9313 2001.01.18 20 S06E01 0100 CAO beta-gamma 9315 2001.01.19 1 S28W09 0000 AXX 9316 2001.01.19 8 S16E23 0100 CAO 9318 2001.01.20 S04W35 plage 9319 2001.01.21 5 S18W70 0030 BXO 9320 2001.01.21 3 S23W25 0010 BXO 9321 2001.01.21 18 S06E43 0160 DAO 9322 2001.01.23 6 S23E00 0010 BXO 9323 2001.01.23 2 S29E03 0000 BXO 9324 2001.01.23 4 N10E42 0060 BXO Total number of sunspots: 78 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.11 191.5 133.2 111.0 (+3.2) 1999.12 169.8 84.6 111.1 (+0.1) 2000.01 158.1 90.1 112.9 (+1.8) 2000.02 174.1 112.9 116.7 (+3.8) 2000.03 208.2 138.5 119.9 (+3.2) 120.8 (+0.9) 2000.04 184.2 125.5 cycle 23 peak candidate 2000.05 184.9 121.6 119.0 (-1.8) 2000.06 179.8 124.9 118.7 (-0.3) 2000.07 202.3 169.1 (120.3 predicted, +1.6) 2000.08 163.0 130.5 (120.8 predicted, +0.5) 2000.09 182.1 109.9 (119.9 predicted, -0.9) 2000.10 167.4 100.1 (118.7 predicted, -1.2) 2000.11 178.8 106.5 (116.8 predicted, -1.9) 2000.12 173.6 104.5 (114.2 predicted, -2.6) 2001.01 167.2 (1) 105.2 (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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]