Solar Terrestrial Activity Report [Image] Last update December 18, 2000 at 03:35 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 17. Solar wind speed ranged between 335 and 396 km/sec under the influence of a weak coronal stream. Solar flare activity was low. Solar flux was 196.7, the planetary A index was 8 (3-hour K indices: 1212 3331, Boulder K indices: 2322 3431). Region 9262 developed slowly and was quiet, C class flares are possible. Region 9264 was mostly unchanged and quiet. Region 9265 decayed slowly and was quiet. Region 9266 rotated off the visible disk. Regions 9267 and 9268 were quiet and stable. Region 9269 was generally quiet. Region 9271 was mostly quiet and stable, the region is spotless early on Dec.18. Region 9272 was quiet and stable, as was region 9273. Region 9275 was quiet and stable. New region 9276 developed very quickly just north of region 9271 near the southwest limb and is already capable of producing minor M class flares. New region 9277 emerged in the northwest quadrant. New region 9278 rotated into view at the northeast limb. Flares and CMEs A total of 11 C class events were recorded on December 17. Region 9271 produced a C2.1 flare at 01:00 UTC. Region 9266 was the source of a C3.7 flare at 05:24 UTC. Region 9276 generated a C2.6 flare at 02:56, a C2.1 flare at 09:06, a C4.0 flare at 12:05, a C3.7 flare at 16:26, a C3.1 flare at 17:47 and a C5.8 flare at 18:40 UTC. 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 18-19. 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 9258 2000.12.07 N14W82 plage 9262 2000.12.08 11 N16W44 0070 DAO 9263 2000.12.09 N18W40 plage 9264 2000.12.10 20 S24W22 0200 EAI 9265 2000.12.10 2 N15W19 0010 AXX 9266 2000.12.11 1 N25W90 0060 HSX 9267 2000.12.11 14 N08W43 0150 CAO 9268 2000.12.13 1 S18E23 0110 HSX 9269 2000.12.13 17 N14E09 0260 DAO 9270 2000.12.13 S10W42 plage 9271 2000.12.14 1 S20W67 0010 AXX 9272 2000.12.14 3 N12W21 0010 BXO 9273 2000.12.15 2 N19E43 0030 HSX 9274 2000.12.16 N16W32 plage 9275 2000.12.16 7 N21W45 0020 BXO 9276 2000.12.17 7 S14W72 0020 DAO beta-gamma 9277 2000.12.17 1 N16W63 0020 HSX 9278 2000.12.17 2 N09E67 0040 HRX Total number of sunspots: 89 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) 2000.12 160.8 (1) 73.2 (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]