Solar Terrestrial Activity Report [Image] Last update December 14, 2001 at 04:40 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 on December 13. Solar wind speed ranged between 288 and 327 km/sec. Solar flare activity was high. Solar flux was 220.2, the planetary A index was 4 (3-hour K indices: 2110 2111, Boulder K indices: 2121 0211). Region 9724 rotated quietly off the visible disk. Region 9727 was mostly unchanged and remains capable of producing a major flare. Region 9732 was quiet and stable. Region 9733 has changed a lot in appearance over the last day, particularly after the major flare. The magnetic delta structure has disappeared, but could soon redevelop. New spots are emerging in several places and further development is likely. Region 9734 decayed and could soon become spotless. Region 9735 once again decayed into spotless plage. Region 9736 was quiet and stable. Region 9737 decayed further and was quiet. Region 9738 was quiet and stable. New region 9739 emerged in the southern hemisphere over the central meridian and appears to be slowly developing. New region 9740 emerged near the southeast limb. New region 9741 rotated into view at the northeast limb. Flares and CMEs A total of 4 C. 2 M and 1 X class events were recorded on December 13. Region 9733 produced a C4.1 flare at 02:41 and an impressive, impulsive major X6.2/3B flare at 14:30 UTC. This event was accompanied by a strong type II and a weak type IV radio sweep. A halo CME was observed shortly afterwards in LASCO C3 images. The CME appears to be a full halo CME but emissions were weak below the south pole. The CME will likely reach Earth sometime between late today and noon on December 15. Region 9727 generated an M1.8 flare at 06:40 and an M1.4/1F flare at 23:07 UTC. December 11: Region 9733 produced a major impulsive X2.8/2B flare at 08:08. This event was accompanied by a moderate type II and a weak type IV radio sweep. A slow partial halo CME was observed off the northeast limb and the north pole. It is uncertain if this CME had any geoeffective extensions. (A filament in the northwest quadrant erupted before noon and caused a partial halo CME off the northwest and most of the southwest limb as well as the north pole.) The background x-ray flux is at the class C1-C2 level. Coronal holes An extension of a large southern hemisphere coronal hole was in a geoeffective position on December 10-12. Forecast The geomagnetic field is expected to be quiet to active on December 14 due to a coronal stream and unsettled to major storm on December 15 due to a CME impact. 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 Location region numbered no. at Area Classification Comment sunspots midnight 9724 2001.12.01 1 N09W88 0010 AXX 9726 2001.12.02 S16W76 plage 9727 2001.12.03 24 S21W66 0630 EKI beta-gamma-delta 9730 2001.12.05 S12W57 plage 9731 2001.12.06 N25W56 plage 9732 2001.12.07 6 N04W18 0070 CAO 9733 2001.12.08 46 N14E04 0490 EKC beta-gamma 9734 2001.12.09 1 S12E24 0020 HSX 9735 2001.12.10 N05W74 plage 9736 2001.12.10 6 S10W69 0090 DSO 9737 2001.12.10 6 S28E13 0030 DSO 9738 2001.12.12 3 S19E53 0060 DAO 9739 2001.12.13 3 S13W02 0010 CSO 9740 2001.12.13 3 S06E56 0020 CSO 9741 2001.12.13 3 N07E72 0010 BXO Total number of sunspots: 102 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) 2001.12 228.6 (1) 91.1 (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]