Solar Terrestrial Activity Report [Image] Last update January 18, 2001 at 03:25 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 unsettled on January 17. Solar wind speed ranged between 321 and 429 km/sec. A weak solar wind shock was observed at ACE at 15:30 UT. Solar wind speed increased abruptly from 380 to 420 km/sec. The interplanetary magnetic field has been mostly northwards after the shock and only a small increase in geomagnetic activity has been observed. The source of the shock is probably the partial halo CME observed on January 14. Solar flare activity was low. Solar flux was 151.9, the planetary A index was 7 (3-hour K indices: 3101 2332, Boulder K indices: 3110 1321). Region 9304 decayed into spotless plage. Region 9306 decayed quickly and was mostly quiet. Region 9308 decayed slowly and was quiet. Region 9311 was quiet and stable, as was region 9312. A couple of regions at the southeast limb could rotate into view today. Flares and CMEs A total of 8 C class events were recorded on January 17. Region 9306 produced a C1.8 flare at 03:52, a C1.1 flare at 11:34 and a C2.3 flare at 20:46 UT. A C2.5 long duration event peaked at 01:55 UTC. Its origin was in a region just behind the southeast limb. Moderate type II and weak type IV sweeps were recorded as well. The background x-ray flux is at the class B5 level. Coronal holes Two very small coronal holes in the southern hemisphere was in a geoeffective position on January 17-18. Any coronal stream originating from these holes is unlikely to influence the geomagnetic field to a significant degree. Forecast The geomagnetic field is expected to be quiet to unsettled on January 18-20. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair. 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 9304 2001.01.07 N11W83 plage 9305 2001.01.07 S06W69 plage 9306 2001.01.08 17 N13W66 0130 FAI beta-gamma 9308 2001.01.10 7 N16W41 0080 DAO 9310 2001.01.14 N26E09 plage 9311 2001.01.15 6 N04E25 0040 DSO 9312 2001.01.16 1 N08E47 0020 HSX Total number of sunspots: 31 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) 2001.01 171.1 (1) 82.0 (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]