Solar Terrestrial Activity Report [Image] Last update December 17, 2001 at 01:15 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update 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 16. Solar wind speed ranged between 447 and 570 km/sec under the influence of a weakening coronal stream. Solar flare activity was moderate. Solar flux was 209.1, the planetary A index was 10 (3-hour K indices: 2333 3222, Boulder K indices: 2233 3221). Region 9732 was quiet and stable. Region 9733 decayed further and lost its magnetic delta structure. M class flares are still possible. Region 9734 decayed and was spotless by early evening. Regions 9737 and 9738 were quiet and stable. Region 9739 developed further and could produce isolated minor M class flares. Region 9741 was quiet and stable. Region 9742 appears to have a magnetic delta structure and could produce M class flares. New region 9743 rotated into view at the southeast limb. New region 9744 emerged in the southeast quadrant. Flares and CMEs A total of 3 C and 2 M class events were recorded on December 16. Region 9733 produced an M1.5/2N flare at 01:24, an M1.0 flare at 03:28 and a C8.5 flare at 07:43 UTC. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on December 17 quiet to unsettled on December 18-19. 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 9732 2001.12.07 1 N02W62 0060 HSX 9733 2001.12.08 47 N14W36 0420 EAI beta-gamma 9734 2001.12.09 2 S15W09 0010 AXX 9737 2001.12.10 4 S28W24 0040 DSO 9738 2001.12.12 12 S19E15 0060 ESO 9739 2001.12.13 15 S13W43 0390 DAO 9740 2001.12.13 S06E16 plage 9741 2001.12.13 4 N05E30 0020 CSO 9742 2001.12.15 11 N08E64 0470 DKI beta-gamma-delta? 9743 2001.12.16 2 S11E73 0240 HAX 9744 2001.12.16 6 S06E25 0030 CAO Total number of sunspots: 104 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) 2001.12 225.9 (1) 110.6 (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]