Solar Terrestrial Activity Report [Image] Last update December 20, 2000 at 05:10 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, 2000) - Has cycle 23 peaked?] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update December 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update December 2, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update October 20, 2000)] Recent development The geomagnetic field was quiet to unsettled on December 19. Solar wind speed ranged between 331 and 390 km/sec. Solar flare activity was low. Solar flux was 198.6, the planetary A index was 6 (3-hour K indices: 2112 2331, Boulder K indices: 2112 2221). Region 9262 decayed and was quiet, the region is rotating over the west limb. Region 9264 was quiet and stable. Region 9265 decayed into spotless plage. Regions 9267 and 9268 were mostly quiet and stable, as were regions 9269 and 9273. Region 9275 decayed into spotless plage. Region 9277 rotated off the visible disk early today. Region 9278 developed further and could produce a minor M class flare. Region 9279 developed slowly and could produce C and perhaps a minor M class flare. New region 9280 rotated into view at the northeast limb, the region appears to be complex in magnetograms and could produce M class flares. Flares and CMEs A total of 9 C class events were recorded on December 19. Region 9267 produced a C2.1 flare at 00:25 and a C2.2 flare at 04:59 UTC. Region 9276 generated a C4.0 flare at 01:59 UTC. Region 9278 was the source of a C9.5 flare at 10:24, a C4.1 flare at 19:00 and a C2.1 flare at 21:40 UTC. Region 9269 produced a C3.0 flare at 14:15 UTC. December 18: Region 9269 produced a C7.0 flare at 11:11 UTC. The flare was accompanied by a moderate type II sweep and a visually weak and slow full halo coronal mass ejection. With the CME occurring near the center of the solar disk Earth will receive an impact, most likely on December 21. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on December 20. A CME will cause unsettled to minor storm conditions on December 21 and maybe even on December 22. 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 9262 2000.12.08 1 N16W74 0000 AXX 9263 2000.12.09 N18W66 plage 9264 2000.12.10 13 S25W49 0120 DSO 9265 2000.12.10 N19W47 plage 9267 2000.12.11 3 N07W72 0110 CSO 9268 2000.12.13 1 S18W04 0090 HSX 9269 2000.12.13 7 N13W18 0030 CSO 9270 2000.12.13 S10W68 plage 9272 2000.12.14 N12W47 plage 9273 2000.12.15 5 N20E20 0010 BXO 9274 2000.12.16 N16W58 plage 9275 2000.12.16 N22W69 plage 9277 2000.12.17 1 N16W89 0000 AXX 9278 2000.12.17 17 N09E37 0090 DAI beta-gamma 9279 2000.12.18 10 S11E54 0190 DSO 9280 2000.12.19 5 N10E72 0260 DAO Total number of sunspots: 63 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 (118.3 predicted, -0.7) 2000.07 202.3 169.1 (119.8 predicted, +1.5) 2000.08 163.0 130.5 (120.5 predicted, +0.7) 2000.09 182.1 109.9 (119.6 predicted, -0.9) 2000.10 167.4 100.1 (118.4 predicted, -1.2) 2000.11 178.8 106.5 (116.4 predicted, -2.0) 2000.12 164.7 (1) 84.1 (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]