Solar Terrestrial Activity Report [Image] Last update December 16, 2001 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 December 2, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update December 2, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update December 2, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update October 16, 2001)] Recent development The geomagnetic field was quiet to unsettled on December 15. Solar wind speed ranged between 336 and 449 km/sec. The interplanetary magnetic field was at times strongly moderately to strongly southwards, usually this would have caused active and even minor storm intervals. Solar wind density was unusually high most of the day, perhaps resulting from a CME embedded in a coronal stream? Solar flare activity was low. Solar flux was 217.8, the planetary A index was 11 (3-hour K indices: 3333 3222, Boulder K indices: 3323 3222). Region 9727 rotated out of view and was mostly quiet. Region 9732 was quiet and stable. Region 9733 decayed slowly but still has many spots and the potential to produce major flares. Region 9734 decayed and could become spotless today. Regions 9737 and 9738 were quiet and stable. Region 9739 developed slowly and could soon become capable of minor M class flaring. Region 9741 was quiet and stable. New region 9742 rotated into view at the northeast limb, the region is capable of M class flaring. Flares and CMEs A total of 10 C class events were recorded on December 15. Region 9733 produced a C6.5 flare at 00:30, a C4.9 flare at 10:10, a C4.3 flare at 17:33, a C2.9 flare at 18:24 and a C3.5 flare at 23:15 UTC. Region 9727 generated a C8.3 flare at 01:01 UTC. The background x-ray flux is at the class C2 level. Coronal holes No obvious coronal holes are approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on December 16 with a possibility of isolated minor storm intervals and quiet to unsettled on December 17-18. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair to 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 9727 2001.12.03 4 S22W88 0320 EAI beta-gamma-delta 9730 2001.12.05 S12W83 plage 9731 2001.12.06 N25W82 plage 9732 2001.12.07 1 N03W49 0050 HSX 9733 2001.12.08 57 N14W23 0430 EAI beta-gamma-delta 9734 2001.12.09 5 S14E01 0020 CAO 9737 2001.12.10 6 S27W12 0070 DAO 9738 2001.12.12 13 S18E27 0060 EAO 9739 2001.12.13 16 S13W30 0120 DAO 9740 2001.12.13 S06E29 plage 9741 2001.12.13 1 N05E43 0030 HRX 9742 2001.12.15 5 N09E73 0150 EAO Total number of sunspots: 108 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.8 2000.10 167.4 99.4 114.5 (-1.8) 2000.11 178.8 106.8 112.7 (-1.8) 2000.12 173.6 104.4 112.0 (-0.7) 2001.01 166.6 95.6 108.7 (-3.3) 2001.02 146.6 80.6 104.1 (-4.6) 2001.03 177.7 113.5 104.8 (+0.7) 2001.04 177.7 107.7 107.6 (+2.8) 2001.05 147.1 96.6 108.7 (+1.1) 2001.06 173.0 134.0 (108.5 predicted, -0.2) 2001.07 131.3 82.2 (108.1 predicted, -0.4) 2001.08 162.9 106.8 (108.7 predicted, +0.6) 2001.09 233.2 150.7 (108.1 predicted, -0.6) 2001.10 207.6 125.6 (105.3 predicted, -2.8) 2001.11 210.6 106.5 (103.7 predicted, -1.6) 2001.12 227.0 (1) 104.0 (2) (100.3 predicted, -3.4) 1) Running average based on the daily 20:00 UT solar flux value at 2800 MHz. 2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number 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]