Solar Terrestrial Activity Report [Image] Last update December 31, 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 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 active on December 30. Solar wind speed ranged between 350 and 731 km/sec. The halo CME observed following the X3 event on December 28 in region 9767 was observed as a solar wind shock at SOHO at 19:38 UTC. Brief and strong southwards excursions of the interplanetary magnetic field was observed soon after the shock. The IMF has, however, been predominantly northwards and has weakened considerably during the first hours of the last day of the year. Solar flare activity was low. Solar flux was 246.6, the planetary A index was 17 (3-hour K indices: 3442 3244, Boulder K indices: 3432 3343). Region 9751 decayed slowly and could produce occasional minor M class flares. Region 9753 developed slowly and quietly. Region 9754 decayed slowly and quietly, occasional minor M class flares are possible. Region 9755 was quiet and stable, as were regions 9756, 9761, 9763, 9764 and 9765. Region 9757 decayed and was spotless by late evening. New region 9766 rotated into view at the northeast limb. New region 9767 rotated into view at the southeast limb revealing a fairly large region with magnetic delta structures both in the northern and southern large penumbras. Major flares are likely. The above 10 MeV proton flux has been increasing slowly early on December 31, the source of this increase is not obvious. Flares and CMEs Only 1 C class event was recorded on December 30, this C5.0 flare at 15:06 UTC had its origin in region 9767. A filament eruption in the southwest quadrant near the southwest limb occurred during the latter half of the day. The background x-ray flux is at the class C2-C3 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on December 31 and quiet to unsettled on January 1. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to 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 Location region numbered no. at Area Classification Comment sunspots midnight 9747 2001.12.19 N12W78 plage 9749 2001.12.20 S08W61 plage 9751 2001.12.21 18 N05W51 0230 EAI beta-gamma 9753 2001.12.22 15 S18W48 0090 DAO 9754 2001.12.23 28 S08W30 0160 FAI beta-gamma 9755 2001.12.25 10 S04W03 0150 DSO 9756 2001.12.26 3 S29E20 0060 CAO 9757 2001.12.26 1 S10W51 0000 AXX now spotless 9758 2001.12.26 N13W32 plage 9759 2001.12.26 N17W24 plage 9760 2001.12.26 N07W18 plage 9761 2001.12.26 1 N10E21 0070 HSX 9762 2001.12.27 N02W33 plage 9763 2001.12.27 4 N06E35 0060 CSO 9764 2001.12.28 6 N13W11 0020 DSO 9765 2001.12.28 5 N06E50 0110 DAO 9766 2001.12.30 3 N05E62 0040 CSO 9767 2001.12.30 4 S23E73 0210 EKI beta-gamma-delta Total number of sunspots: 98 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 (109.3 predicted, +0.6) 2001.07 131.3 82.2 (109.8 predicted, +0.5) 2001.08 162.9 106.8 (110.3 predicted, +0.5) 2001.09 233.2 150.7 (109.7 predicted, -0.6) 2001.10 207.6 125.6 (107.0 predicted, -2.7) 2001.11 210.6 106.5 (105.3 predicted, -1.7) 2001.12 234.8 (1) 210.8 (2) (102.0 predicted, -3.3) 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]