Solar Terrestrial Activity Report [Image] Last update December 23, 2000 at 01:30 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 22. Solar wind speed ranged between 283 and 334 km/sec. A solar wind shock was observed at 18:10 UTC at ACE. Initially this seemed to be the start of a fairly benign disturbance, however, the interplanetary magnetic field gradually strengthened and was strongly southwards after 21h UTC. Solar flare activity was low. Solar flux was 190.0, the planetary A index was 7 (3-hour K indices: 1112 1323, Boulder K indices: 1222 1113). Region 9264 was quiet and stable and is rotating over the west limb. Region 9268 was mostly quiet and stable, as were regions 9269 and 9273. Region 9278 decayed slowly and was quiet. Region 9279 was mostly unchanged and quiet. Region 9280 developed slowly and is capable of producing a major flare. Two of the largest penumbras seems to be merging and this could create a strong magnetic delta configuration. Region 9281 was quiet and stable, the region appears to be spotless early on Dec.23. Region 9282 was quiet and stable. New region 9283 rotated partly into view at the southeast limb. The region is quite active and may be capable of minor M class flare production. Flares and CMEs A total of 12 C class events were recorded on December 22. Region 9269 produced a C1.4 flare at 02:50 UTC. Region 9280 generated a C1.8 flare at 03:15 and a C2.6 flare at 19:34 UTC. Region 9283 was the source of a C2.0 flare at 23:20 and a C3.7 flare at 23:52 UTC. December 20: A filament eruption was observed in the northern hemisphere near the central meridian starting at 11:48 UTC in LASCO EIT images. This eruption may have caused a geoeffective CME which could influence the geomagnetic field on December 23. The background x-ray flux is at the class B9 level. Coronal holes A small coronal hole in the southern hemisphere was in a geoeffective position on December 21. Forecast The geomagnetic field is expected to be quiet to active on December 23 with a possibility of isolated minor storm intervals. A weak coronal stream could cause unsettled conditions on December 24. 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 no. Location at region numbered sunspots midnight Area Classification Comment 9264 2000.12.10 1 S26W83 0030 AXX 9265 2000.12.10 N19W86 plage 9268 2000.12.13 4 S18W43 0080 CSO 9269 2000.12.13 4 N15W53 0010 AXX 9272 2000.12.14 N14W84 plage 9273 2000.12.15 2 N20W20 0000 AXX 9278 2000.12.17 12 N09W05 0070 DAO 9279 2000.12.18 9 S13E11 0110 ESO 9280 2000.12.19 25 N09E35 0540 EKI beta-gamma 9281 2000.12.20 5 N06E06 0020 CSO 9282 2000.12.21 1 N19E54 0040 HSX 9283 2000.12.22 1 S15E79 0120 HAX Total number of sunspots: 64 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) 2000.12 168.9 (1) 100.1 (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]